gigs.md

Documentation for the gigs package.

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Assess Fetal, Newborn, and Child Growth with International Standards

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Version information:

• Package: gigs
• Version: 0.1.8
• Generated: 2024-11-21T17:32:25
• Author(s): Bartosz Jablonski (yabwon@gmail.com), Simon Parker (simon.parker.24@ucl.ac.uk), Linda Vesel, Eric Ohuma (eric.ohuma@lshtm.ac.uk)
• Maintainer(s): Bartosz Jablonski (yabwon@gmail.com)
• License: GNU General Public License v3.0
• File SHA256: F*153695E7C4F007D2BFF34ACF7F666D95150F52E27ADA710EFEC8CD8FE2F804D0 for this version
• Content SHA256: C*C6B2B9B3B715F6D4CF01316EFF20F327394FC8F8D3B1CE47DFCB99BA3F6F778E for this version

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The gigs package, version: 0.1.8;

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gigs SAS Package

Overview

Produced as part of the Guidance for International Growth Standards project at the London School of Hygiene & Tropical Medicine, gigs provides a single, simple interface for working with the WHO Child Growth standards and outputs from the INTERGROWTH-21^st project. You will find functions for converting from anthropometric measures (e.g. weight or length) to z-scores and centiles, and the inverse. Also included are functions for classifying newborn and infant growth according to literature-based cut-offs.

gigs is of use to anyone interested in fetal and child growth, including child health researchers, policymakers, and clinicians. This package is best suited to growth data where the gestational age (GA) of each child is known, as the use of the growth standards included in gigs is GA-dependent. We recommend you check out the available standards section to see if your anthropometric measurements can be converted to z-scores/centiles by gigs. We recommend using gigs to generate continuous or categorical measures of fetal/newborn/child growth, which can then be used in downstream analyses.

Installation

Installing the SAS packages framework

gigs works with the SAS Packages Framework (SPF), so installing gigs requires that the SPF is installed. First, create a directory where the SPF and packages will be stored. This can be at any directory you choose, for example:

• D:\SAS_Packages
• /home/myuser/myPackages

SPF is designed in such a way that this directory you've made must be refered to by fileref packages. In your SAS session (preferably at the beginning), you should run the following code:

filename packages "/path/to/packages/directory";

Installing an SPF package, "in a nutshell", means copying SPFinit.sas (from packagename.zip) file into the packages directory. This can be done automatically or manually.

Installing gigs - automatic

To install gigs automatically, your SAS session must have access to the internet.

The following code will install the SAS Packages Framework, gigs, and macroArray (required for gigs to work). You only need to execute this code once:

filename packages "/path/to/packages/directory";
filename SPFinit url
 "https://raw.githubusercontent.com/yabwon/SAS_PACKAGES/main/SPF/SPFinit.sas";
%include SPFinit;

%installPackage(SPFinit gigs macroArray)

filename SPFinit clear;

After running this code, check the log to see if the process was successful.

Installing gigs - manual

If your SAS session does not have access to the internet but you can copy files manually to your packages directory, you can install gigs like so:

• Download SPFinit.sas from here
• Download gigs.zip from here
• Download macroarray.zip from here

Once downloaded, copy these files manually to your SAS packages directory.

Using gigs in a SAS session

To use gigs in a new SAS session, you must enable the SAS Packages Framework, then load gigs with %loadPackage:

filename packages "/path/to/packages/directory";
%include packages(SPFinit.sas);
%loadPackage(gigs)

The macroArray package will be loaded automatically when gigs is loaded.

If using gigs often in your work, the most convenient/practical way to load gigs is to put those three lines of code in your autoexec.sas file.

Links to SAS Package Framework materials

The SAS Packages Framework (SPF)

Location of the SAS Packages Repository

Workshop materials

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Rationale + terminology

When working with growth measurements from individual children, it is helpful to compare those measurements to a growth standard, which represents average growth for an population of children. This allows assessment of individual growth - for example, that a baby was born small, but later caught up to its peers in size. It also allows you to compare measurements from different children.

These standards of growth can be made in different ways, but the best studies utilise international samples made of up thousands of healthy fetuses, newborns, or children. In gigs, you’ll find different international growth standards, allowing you to compare growth measures from children with different ages, weights, heights, and more.

In general, you’ll use gigs to transform raw growth measures to z-scores or centiles. Z-scores and centiles represent the location of a measurement within a normal distribution of values, such that:

• A z-score is the number of standard deviations from the mean for a given anthropometric measurement (e.g. height or weight).
• A centile represents the proportion of measurements in some distribution which we would expect to be lower than a measurement we’ve taken. In gigs, these are represented as a value between 0 and 1. For example, 0.5 corresponds to the 50^th centile (i.e. the mean), whereas 0.75 corresponds to the 75^th centile.

In growth data, z-scores and centiles represent the size a fetus, newborn, or child relative to its peers. Size here is considered relative to a standardising variable, which is usually age but could also be another variable such as their length. By tracking a child’s relative size as they grow, you can see if they are achieving their growth potential or not. If not, this may indicate underlying issues such as ill health or undernutrition.

Classification functions

gigs includes a number of functions which permit fast identification of at-risk infants through classification of suboptimal growth. The cut-offs used are sourced from research literature; you can check the function documentation to see these sources.

Available international growth standards

gigs facilitates the proper use of international growth standards, which are growth charts developed using international samples of healthy singleton children born to mothers that had their health needs met during pregnancy. They represent an international standard of 'optimal' growth. gigs implements international growth standards from the WHO and INTERGROWTH-21^st project:

• ig_nbs - INTERGROWTH-21^st Newborn Size standards (including very preterm)

  Component standards

  Acronym	Description	Unit	gest_days range
  wfga	weight-for-GA	kg	168 to 300 days
  lfga	length-for-GA	cm	168 to 300 days
  hcfga	head circumference-for-GA	cm	168 to 300 days
  wlrfga	weight-to-length ratio-for-GA	kg/cm	168 to 300 days
  ffmfga	fat-free mass-for-GA	kg	266 to 294 days
  bfpfga	body fat percentage-for-GA	%	266 to 294 days
  fmfga	fat mass-for-GA	kg	266 to 294 days

• ig_png - INTERGROWTH-21^st Postnatal Growth of Preterm Infants standards

  Component standards

  Acronym	Description	Unit	x range
  wfa	weight-for-age	kg	27 to ≤64 exact weeks
  lfa	length-for-age	cm	27 to ≤64 exact weeks
  hcfa	head circumference-for-age	cm	27 to ≤64 exact weeks
  wfl	weight-for-length	kg	35 to 65 cm

• ig_fet - INTERGROWTH-21^st Fetal standards

  Component standards

  Acronym	Description	Unit	x range
  hcfga	head circumference-for-GA	mm	98 to 280 days
  bpdfga	biparietal diameter-for-GA	mm	98 to 280 days
  acfga	abdominal circumference-for-GA	mm	98 to 280 days
  flfga	femur length-for-GA	mm	98 to 280 days
  ofdfga	occipito-frontal diameter for-GA	mm	98 to 280 days
  efwfga	estimated fetal weight-for-GA	g	154 to 280 days
  sfhfga	symphisis-fundal height-for-GA	mm	112 to 294 days
  crlfga	crown-rump length-for-GA	mm	58 to 105 days
  gafcrl	GA-for-crown-rump length	days	15 to 95 mm
  gwgfga	gestational weight gain-for-GA	kg	98 to 280 days
  pifga	pulsatility index-for-GA		168 to 280 days
  rifga	resistance index-for-GA		168 to 280 days
  sdrfga	systolic/diastolic ratio-for-GA		168 to 280 days
  tcdfga	transcerebellar diameter-for-GA	mm	98 to 280 days
  tcdfga	GA-for-transcerebellar diameter	mm	98 to 280 days
  poffga	parietal-occipital fissure-for-GA	mm	105 to 252 days
  sffga	Sylvian fissue-for-GA	mm	105 to 252 days
  avfga	anterior horn of the lateral ventricle-for-GA	mm	105 to 252 days
  pvfga	atrium of the posterior horn of the lateral ventricle-for-GA	mm	105 to 252 days
  cmfga	cisterna magna-for-GA	mm	105 to 252 days
  hefwfga	Hadlock estimated fetal weight-for-GA	g	126 to 287 days

• who_gs - WHO Child Growth Standards for term infants

  Component standards

  Acronym	Description	Unit	x range
  wfa	weight-for-age	kg	0 to 1856 days
  bfa	BMI-for-age	kg/m2	0 to 1856 days
  lhfa	length/height-for-age	cm	0 to 1856 days
  hcfa	head circumference-for-age	cm	0 to 1856 days
  wfl	weight-for-height	kg	45 to 110 cm
  wfh	weight-for-length	kg	65 to 120 cm
  acfa	arm circumference-for-age	cm	91 to 1856 days
  ssfa	subscapular skinfold-for-age	mm	91 to 1856 days
  tsfa	triceps skinfold-for-age	mm	91 to 1856 days

Funding

Bill & Melinda Gates Foundation

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---

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Required SAS Components:

• Base SAS Software

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Required SAS Packages:

• macroArray (1.2.6)

---

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SAS package generated by SAS Package Framework, version 20241102

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The gigs package content

The gigs package consists of the following content:

1. _tmpgigs libname

2. _tmpgigs.ig_nbs_bc_li data

3. _tmpgigs.ig_nbs_coeffs data

4. _tmpgigs.life6mo data

5. _tmpgigs.who_lms_parameters_data data

6. _tmpgigs.ig_fet_centiles_data lazydata

7. _tmpgigs.ig_fet_zscores_data lazydata

8. _tmpgigs.ig_nbs_centiles_data lazydata

9. _tmpgigs.ig_nbs_zscores_data lazydata

10. _tmpgigs.ig_png_centiles_data lazydata

11. _tmpgigs.ig_png_zscores_data lazydata

12. _tmpgigs.life6mo_expected lazydata

13. _tmpgigs.who_gs_centiles_data lazydata

14. _tmpgigs.who_gs_zscores_data lazydata

15. gigs_ig_fet_estimate_ga_crl() function

16. gigs_ig_png_equations() function

17. gigs_ig_fet_estimate_ga() function

18. gigs_ig_fet_value2zscore() function

19. gigs_ig_fet_zscore2value() function

20. gigs_ig_png_centile2value() function

21. gigs_ig_png_value2centile() function

22. gigs_ig_png_value2zscore() function

23. gigs_ig_png_zscore2value() function

24. gigs_who_gs_value2zscore() function

25. gigs_who_gs_zscore2value() function

26. gigs_ig_fet_centile2value() function

27. gigs_ig_fet_value2centile() function

28. gigs_ig_nbs_centile2value() function

29. gigs_ig_nbs_value2centile() function

30. gigs_who_gs_centile2value() function

31. gigs_who_gs_value2centile() function

32. gigs_ig_nbs_value2zscore() function

33. gigs_ig_nbs_zscore2value() function

34. %gigs_ig_fet_acronym() macro

35. %gigs_ig_nbs_acronym() macro

36. %gigs_ig_png_acronym() macro

37. %gigs_who_gs_acronym() macro

38. gigs_acronym_functions exec

39. gigs_acronym_functions clean

40. gigs_categorise_sfga() function

41. gigs_compute_sfga() function

42. gigs_categorise_headsize() function

43. gigs_categorise_stunting() function

44. gigs_categorise_svn() function

45. gigs_categorise_wasting() function

46. gigs_categorise_wfa() function

47. gigs_compute_headsize() function

48. gigs_compute_stunting() function

49. gigs_compute_svn() function

50. gigs_compute_wasting() function

51. gigs_compute_wfa() function

52. gigs_classify_headsize() function

53. gigs_classify_sfga() function

54. gigs_classify_stunting() function

55. gigs_classify_svn() function

56. gigs_classify_wasting() function

57. gigs_classify_wfa() function

58. %gigs_classify_growth() macro

59. License note

---

_tmpgigs libname

The _tmpGIGS library stores temporary data sets generated during the gigs package load.

If possible a subdirectory of the WORK location is created, like:

LIBNAME _tmpGIGS BASE "%sysfunc(pathname(WORK))/gigs_package_temporary_data";

If not possible, then redirects to the WORK location, like:

LIBNAME _tmpGIGS (WORK); 

---

---

_tmpgigs.ig_nbs_bc_li data

Internal gigs package data. Contains coefficients for INTERGROWTH-21^st Newborn Size standard for body composition (fat mass-for-GA; fat-free mass-for-GA; body fat %-for-GA).

---

_tmpgigs.ig_nbs_coeffs data

gigs package data.

INTERGROWTH-21^st Newborn Size Standards GAMLSS coefficients

Description

This table has mu, sigma, nu and tau coefficient values for the INTERGROWTH-21^st Newborn Size standards which are based on the skew T type 3 distribution:

• Weight-for-gestational age from 231 to 300 days
• Length-for-gestational age from 231 to 300 days
• Head circumference-for-gestational age from 231 to 300 days

These coefficients are grouped by acronym, then sex. Within each group, gest_days establishes the order of mu/sigma/nu/tau values.

References

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Source

Raw mu/sigma/nu/tau values were provided by Dr Eric Ohuma.

---

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_tmpgigs.life6mo data

gigs package data.

Data extract from the Low birthweight Infant Feeding Exploration (LIFE) study

Description

A subset of anthropometric data for 300 singleton infants enrolled in the Low birthweight Infant Feeding Exploration (LIFE) study.

Variables are as follows:

• id - Unique ID for each infant in the dataset (1--300).
• sex - Sex of the infant (M = Male; F = Female).
• visitweek - Chronological age in weeks (+1/-1) when study visit occurred (0--26).
• gest_days - Best obstetric estimate of gestational age in days (181--291).
• age_days - Chronological age in days at each visit; equal to pma - gestage (0--242).
• pma - Post-menstrual age in days (182--528).
• wt_kg - Mean weight in kg (1.240--9.40667).
• len_cm - Mean length in cm (37.37--72.93).
• headcirc_cm - Mean head circumference in cm (23.20--44.87).
• muac_cm - Mean mid-upper arm circumference in cm (6.30--16.83).

Note

We subsetted the full LIFE 6 month dataset for gigs. As such, this extract only includes data from 300 singleton pregnancies where the best estimate of gestational age was >168 days. We also removed rows in the full LIFE dataset corresponding to visit weeks where no measurement data was taken due to non-attendance of the visit.

References

Vesel L, Bellad RM, Manji K, Saidi F, Velasquez E, Sudfeld C, et al. Feeding practices and growth patterns of moderately low birthweight infants in resource-limited settings: results from a multisite, longitudinal observational study. BMJ Open 2023, 13(2):e067316. doi: 10.1136/BMJOPEN-2022-067316

---

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_tmpgigs.who_lms_parameters_data data

gigs package data.

WHO Child Growth Standards LMS coefficients

Description

A table with lambda/mu/sigma values for the WHO Child Growth Standards. LMS values are organised by each acronym, then sex, then the x variable which is relevant to each acronym (either age, length/height, or BMI).

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Cole TJ. The LMS method for constructing normalized growth standards. Eur J Clin Nutr. 1990, 44(1):45-60. PMID: 2354692

Source

WHO Child Growth Standards

---

---

_tmpgigs.ig_fet_centiles_data lazydata

gigs package lazy data with centile growth curves for the INTERGROWTH-21^st Fetal standards.

Description

A data set with reference values for different centiles at valid gestational ages in days.

Source

INTERGROWTH-21^st Pregnancy Dating (CRL)

INTERGROWTH-21^st Symphysis-Fundal Height standard

INTERGROWTH-21^st Fetal Growth standards

INTERGROWTH-21^st Fetal Doppler standards

INTERGROWTH-21^st Gestational Weight Gain standard

Note

Some cells are missing data values, because the different Fetal standards were published using different centiles - so some have data for e.g. the 25th centile, whilst others do not.

References

Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):869-79. doi: 10.1016/S0140-6736(14)61490-2

Stirnemann J, Villar J, Salomon LJ, Ohuma EO, Lamber A, Victoria CG et al. International Estimated Fetal Weight Standards of the INTERGROWTH-21st Project. Ultrasound Obstet Gynecol 2016, 49:478-486 doi: 10.1002/uog.17347

Papageorghiou AT, Ohuma EO, Gravett MG, Lamber A, Noble JA, Pang R et al. International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: prospective cohort study in eight countries. BMJ 2016, 355:i5662 doi: 10.1136/bmj.i5662

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Cheikh Ismail L, Bishop DC, Pang R, Ohuma EO, Kac G, Abrams B et al. Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352:i555 doi: 10.1136/bmj.i555

Drukker L, Staines-Urias E, Villar J, Barros FC, Carvalho M, Munim S et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project. Am J Obstet Gynecol 2021, 222(6):602.e1-602.e15 \doi{10.1016/j.ajog.2020.01.012} doi: 10.1016/j.ajog.2020.01.012

Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2021, 57(4):614-623 doi: 10.1002/uog.22017

Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B et al. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2020, 56(3):359-370 doi: 10.1002/uog.21990

Stirnemann J, Salomon LJ, Papageorghiou AT. INTERGROWTH-21st standards for Hadlock's estimation of fetal weight Ultrasound Obstet Gynecol 2020, 56(6):946-948 doi: 10.1002/uog.22000

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.ig_fet_centiles_data)

---

---

_tmpgigs.ig_fet_zscores_data lazydata

gigs package lazy data with z-score growth curves for the INTERGROWTH-21^st Fetal standards.

Description

A data set with reference values for different z-scores at valid gestational ages in days.

Source

INTERGROWTH-21^st Pregnancy Dating (CRL)

INTERGROWTH-21^st Symphysis-Fundal Height standard

INTERGROWTH-21^st Fetal Growth standards

INTERGROWTH-21^st Fetal Doppler standards

INTERGROWTH-21^st Gestational Weight Gain standard

Note

Some INTERGROWTH-21^st Fetal standards were only published with centile tables, so not all of the INTERGROWTH-21^st Fetal standards are present in this table of z-score data.

References

Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):869-79. doi: 10.1016/S0140-6736(14)61490-2

Stirnemann J, Villar J, Salomon LJ, Ohuma EO, Lamber A, Victoria CG et al. International Estimated Fetal Weight Standards of the INTERGROWTH-21st Project. Ultrasound Obstet Gynecol 2016, 49:478-486 doi: 10.1002/uog.17347

Papageorghiou AT, Ohuma EO, Gravett MG, Lamber A, Noble JA, Pang R et al. International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: prospective cohort study in eight countries. BMJ 2016, 355:i5662 doi: 10.1136/bmj.i5662

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Cheikh Ismail L, Bishop DC, Pang R, Ohuma EO, Kac G, Abrams B et al. Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352:i555 doi: 10.1136/bmj.i555

Drukker L, Staines-Urias E, Villar J, Barros FC, Carvalho M, Munim S et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project. Am J Obstet Gynecol 2021, 222(6):602.e1-602.e15 \doi{10.1016/j.ajog.2020.01.012} doi: 10.1016/j.ajog.2020.01.012

Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2021, 57(4):614-623 doi: 10.1002/uog.22017

Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B et al. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2020, 56(3):359-370 doi: 10.1002/uog.21990

Stirnemann J, Salomon LJ, Papageorghiou AT. INTERGROWTH-21st standards for Hadlock's estimation of fetal weight Ultrasound Obstet Gynecol 2020, 56(6):946-948 doi: 10.1002/uog.22000

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.ig_fet_zscores_data)

---

---

_tmpgigs.ig_nbs_centiles_data lazydata

gigs package lazy data with centile growth curves for the INTERGROWTH-21^st Newborn Size standards (including very preterm).

Description

A data set with reference values for different centiles at valid gestational ages in days.

Source

INTERGROWTH-21^st Newborn Size in Very Preterm Infants

INTERGROWTH-21^st Newborn Size Standards

INTERGROWTH-21^st Newborn Size Standards - Body Composition

Note

The tables in this package are combined versions of the tables published by Villar et al. (2014) and Villar et al. (2016), so they cover 168 to 300 days' gestational age. The body composition tables (ffmfga, bfpfga, and fmfga) cover a smaller gestational age span, ranging from only 266 to 294 days' (38 to 42 weeks') gestational age.

References

Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH et al. INTERGROWTH-21st very preterm size at birth reference charts. Lancet 2016, 387(10021):844-45. doi: 10.1016/S0140-6736(16)00384-6

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Villar J, Puglia FA, Fenton TR, Ismal LC, Staines-Urias E, Giuliani F, et al. Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project. Pediatric Research 2017, 82:305-316. doi: 10.1038/pr.2017.52

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.ig_nbs_centiles_data)

---

---

_tmpgigs.ig_nbs_zscores_data lazydata

gigs package lazy data with z-score growth curves for the INTERGROWTH-21^st Newborn Size standards (including very preterm).

Description

A data set with reference values for different z-scores at valid gestational ages in days.

Source

INTERGROWTH-21^st Newborn Size in Very Preterm Infants

INTERGROWTH-21^st Newborn Size Standards

INTERGROWTH-21^st Newborn Size Standards - Body Composition

Note

The tables in this package are combined versions of the tables published by Villar et al. (2014) and Villar et al. (2016), so they cover 168 to 300 days' gestational age. The body composition tables (ffmfga, bfpfga, and fmfga) cover a smaller gestational age span, ranging from only 266 to 294 days' (38 to 42 weeks') gestational age.

References

Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH et al. INTERGROWTH-21st very preterm size at birth reference charts. Lancet 2016, 387(10021):844-45. doi: 10.1016/S0140-6736(16)00384-6

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Villar J, Puglia FA, Fenton TR, Ismal LC, Staines-Urias E, Giuliani F, et al. Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project. Pediatric Research 2017, 82:305-316. doi: 10.1038/pr.2017.52

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.ig_nbs_zscores_data)

---

---

_tmpgigs.ig_png_centiles_data lazydata

gigs package lazy data with z-score growth curves for the INTERGROWTH-21^st Postnatal Growth Standards.

Description

A data set with reference values for different centiles at x variables, either post-menstrual age in weeks or length in cm.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

Source

INTERGROWTH-21^st Postnatal Growth of Preterm Infants

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.ig_png_centiles_data)

---

---

_tmpgigs.ig_png_zscores_data lazydata

gigs package lazy data with z-score growth curves for the INTERGROWTH-21^st Postnatal Growth Standards.

Description

A data set with reference values for different z-scores at x variables, either post-menstrual age in weeks or length in cm.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

Source

INTERGROWTH-21^st Postnatal Growth of Preterm Infants

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.ig_png_zscores_data)

---

---

_tmpgigs.life6mo_expected lazydata

Internal gigs package lazy data. Required to perform tests.

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.life6mo_expected)

---

---

_tmpgigs.who_gs_centiles_data lazydata

gigs package lazy data with centile growth curves for the WHO Child Growth standards.

Description

A data set with reference values at different centiles for valid x values (usually age in days, also length or height in cm for weight-for-length (wfl) and weight-for-height (wfh) standards, respectively).

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Source

WHO Child Growth Standards

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.who_gs_centiles_data)

---

---

_tmpgigs.who_gs_zscores_data lazydata

gigs package lazy data with z-score growth curves for the WHO Child Growth standards.

Description

A data set with reference values at different z-scores for valid x values (usually age in days, also length or height in cm for weight-for-length (wfl) and weight-for-height (wfh) standards, respectively).

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Source

WHO Child Growth Standards

Loading data to SAS

Run the following snippet to load the data set to SAS session:

  %loadPackage(gigs, lazyData=_tmpgigs.who_gs_zscores_data)

---

---

gigs_ig_fet_estimate_ga_crl() function

Estimate gestational age using crown-rump length in mm

Syntax

function gigs_ig_fet_estimate_ga_crl(
  crl_mm
);

---

Arguments

1. crl_mm - Crown-rump length value(s) in mm taken from an ultrasound scan obtained 56 to 97 days since the last menstrual period.

Returns

Numeric variable with gestational age estimate(s) in days.

See also

This function uses gigs_ig_fet_mu_sigma subroutine internally.

References

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

---

---

gigs_ig_png_equations() function

INTERGROWTH-21^st Postnatal Growth of Preterm Infants standards: mu/sigma equations

Estimates median and standard deviation for different measures of postnatal growth in preterm infants.

Syntax

subroutine gigs_ig_png_equations(
  xIN
, sex $
, acronym $
, mu
, sigma
, logarithmic
);
  OUTARGS mu, sigma, logarithmic;

---

Arguments

1. sex - Character variable with sex(es), either "M" (male) or "F" (female).

2. pma_weeks - Numeric variable with post-menstrual age(s) in exact weeks. Elements not between 27 and 64 will return invalid results.

3. acronym - Character variable with acronym(s) denoting an INTERGROWTH-21^st Postnatal Growth standard. Should be one of "wfa" (weight-for-age), "lfa" (length-for-age), "hcfa" (head circumference-for-age), or "wfl" (weight-for-length).

4. mu - Numeric variable, of category OUTARGS, with mu parameter value returned for particular combination of gest_days, sex, and acronym.

5. sigma - Numeric variable, of category OUTARGS, with sigma parameter value returned for particular combination of gest_days, sex, and acronym.

6. logarithmic - Numeric variable, of category OUTARGS, which returns 1 for acronyms "wfa" and "lfa" and 0 otherwise.

Note

The weight-for-age and length-for-age standards are logarithmic, so require slightly different treatment to use in z-score conversions. In contrast, head circumference for gestational age returns the median and standard deviation with no logarithm applied. The weight-for-length standard is not within the provided reference, but was instead supplied directly by Dr Eric Ohuma.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

---

---

gigs_ig_fet_estimate_ga() function

Estimate gestational age using INTERGROWTH-21^st predictive equations

Syntax

function gigs_ig_fet_estimate_ga(
  crl_mm /*=. NULL*/
, headcirc_mm /*=. NULL*/
, femurlen_mm /*=. NULL*/
);

---

Arguments

1. crl_mm - Crown-rump length value(s) in mm taken from an ultrasound scan obtained 56 to 97 days since the last menstrual period.

2. headcirc_mm - Head circumference value(s) in cm taken from an ultrasound scan obtained 98 to 181 days since the last menstrual period.

3. femurlen_mm - Head length value(s) in cm, measured at the same time as the value(s) in headcirc_mm.

Returns

Estimated gestational age(s) in days.

Note

The function will attempt to estimate the gestational age (GA) in three steps, from highest to lowest accuracy. First, using crown-rump length measurements obtained in early pregnancy, then with both head circumference and femur length measurements, and finally with head circumference alone.

References

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Papageorghiou AT, Kemp B, Stones W, Ohuma EO, Kennedy SH, Purwar M et al. Ultrasound-based gestational age estimation in late pregnancy. Ultrasound Obstet Gynecol 2016. 48(6):719-26 doi: 10.1002/uog.15894

Examples

1. Estimate gestational age in 3 different ways

data have;
  input crl_mm headcirc_mm femurlen_mm;
CARDS4;
40 250 55
41 251 56
42 252 57
43 253 58
44 254 59
45 255 60
;;;;
run;

data get;
  set have;
  
  estimate1 = gigs_ig_fet_estimate_ga(
    crl_mm,
    .,
    .
  );

  estimate2 = gigs_ig_fet_estimate_ga(
    .,
    headcirc_mm,
    femurlen_mm
  );

  estimate3 = gigs_ig_fet_estimate_ga(
    crl_mm,
    headcirc_mm,
    femurlen_mm
  );
run;

---

---

gigs_ig_fet_value2zscore() function

Convert values to z-scores in the INTERGROWTH-21^st Fetal Growth standards

Syntax

function gigs_ig_fet_value2zscore(
  y
, x
, acronym $
);

---

Arguments

1. y - Numeric variable with values to convert to z-scores/centiles.

2. x - Numeric variable with x values. Elements should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 98 and 280 days for "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", and "tcdfga".
   • Between 154 and 280 days for "efwfga".
   • Between 112 and 294 days for "sfhfga".
   • Between 58 and 105 days for "crlfga".
   • Between 19 and 95 mm for "gafcrl".
   • Between 105 and 280 days for "gwgfga".
   • Between 168 and 280 days for "pifga", "rifga", and "sdrfga" (the INTERGROWTH-21^st Fetal Doppler standards).
   • Between 105 and 252 days for "poffga", "sffga", "avfga", and "pvfga" (the INTERGROWTH-21^st Fetal Brain Development standards).
   • Between 126 and 287 days for "hefwfga" (the INTERGROWTH-21^st standard for Hadlock-based estimated fetal weight).

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

   Numeric variable gest_days, crl_mm, or tcd_mm are standard-specific x variables.

3. acronym - Character variable denoting the INTERGROWTH-21^st Fetal Growth standard(s) in use. Each value should be one of:

   • "hcfga" (head circumference-for-GA)
   • "bpdfga" (biparietal diameter-for-GA)
   • "acfga" (abdominal circumference-for-GA)
   • "flfga" (femur length-for-GA)
   • "ofdfga" (occipito-frontal diameter-for-GA)
   • "efwfga" (estimated fetal weight-for-GA)
   • "sfhfga" (symphisis-fundal height-for-GA)
   • "crlfga" (crown-rump length-for-GA)
   • "gafcrl" (GA-for-crown-rump length)
   • "gwgfga" (gestational weight gain-for-GA)
   • "pifga" (pulsatility index-for-GA)
   • "rifga" (resistance index-for-GA)
   • "sdrfga" (systolic/diastolic ratio-for-GA)
   • "tcdfga" (transcerebellar diameter-for-GA)
   • "poffga" (parieto-occipital fissure-for-GA)
   • "sffga" (Sylvian fissure-for-GA)
   • "avfga" (anterior horn of lateral ventricle-for-GA)
   • "pvfga" (atrium of posterior horn of lateral ventricle-for-GA)
   • "cmfga" (cisterna magna-for-GA)
   • "hefwfga" (Hadlock esimated fetal weight-for-GA)

   If elements in acronym are not one of the above values, gigs will return missing value (.).

Returns

Numeric variable of expected z-scores for each measurement.

Note

For each acronym from the list: "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", "efwfga", "sfhfga", "crlfga", "gafcrl", "gwgfga", "pifga", "rifga", "sdrfga", "tcdfga", "poffga", "hefwfga", "sffga", "avfga", "pvfga", and "cmfga" a counterpart "acronym function", which is a wrapper for the gigs_ig_fet_value2zscore, is generated. The "acronym function" has the following form:

gigs_ig_fet_<acronym>_value2zscore(y, x)

Complete list is:

gigs_ig_fet_hcfga_value2zscore(headcirc_mm, gest_days)

gigs_ig_fet_bpdfga_value2zscore(bpd_mm, gest_days)

gigs_ig_fet_acfga_value2zscore(abdocirc_mm, gest_days)

gigs_ig_fet_flfga_value2zscore(femurlen_mm, gest_days)

gigs_ig_fet_ofdfga_value2zscore(ofd_mm, gest_days)

gigs_ig_fet_efwfga_value2zscore(efw_g, gest_days)

gigs_ig_fet_hefwfga_value2zscore(hadlock_efw_g, gest_days)

gigs_ig_fet_sfhfga_value2zscore(sfh_cm, gest_days)

gigs_ig_fet_crlfga_value2zscore(crl_mm, gest_days)

gigs_ig_fet_gafcrl_value2zscore(gest_days, crl_mm)

gigs_ig_fet_gwgfga_value2zscore(gest_wt_gain_kg, gest_days)

gigs_ig_fet_pifga_value2zscore(puls_idx, gest_days)

gigs_ig_fet_rifga_value2zscore(resist_idx, gest_days)

gigs_ig_fet_sdrfga_value2zscore(sys_dia_ratio, gest_days)

gigs_ig_fet_tcdfga_value2zscore(tcd_mm, gest_days)

gigs_ig_fet_gaftcd_value2zscore(gest_days, tcd_mm)

gigs_ig_fet_poffga_value2zscore(par_occ_fiss_mm, gest_days)

gigs_ig_fet_sffga_value2zscore(sylv_fiss_mm, gest_days)

gigs_ig_fet_avfga_value2zscore(ant_hlv_mm, gest_days)

gigs_ig_fet_pvfga_value2zscore(atr_phlv_mm, gest_days)

gigs_ig_fet_cmfga_value2zscore(cist_mag_mm, gest_days)

Parameters meaning:

• gest_days - Numeric variable that is usually used as the x variable, but can also be a y variable for the "gafcrl" and "gaftcd" standards.

• headcirc_mm - Numeric variable with head circumference measurements in mm.

• bpd_mm - Numeric variable with biparietal diameter measurement(s) in mm.

• abdocirc_mm - Numeric variable with abdominal circumference measurement(s) in mm.

• femurlen_mm - Numeric variable with femur length(s) in mm.

• ofd_mm - Numeric variable with in occipito-frontal diameter(s) in mm.

• efw_g - Numeric variable with estimated fetal weight(s) in g.

• hadlock_efw_g - Numeric variable with estimated fetal weight(s) in g.

• sfh_cm - Numeric variable with symphisis-fundal height(s) in mm.

• crl_mm - Numeric variable with crown-rump length(s) in mm.

• gest_wt_gain_kg - Numeric variable with gestational weight gain(s)/loss(es) in kg.

• puls_idx - Numeric variable with pulsatility index value(s).

• resist_idx - Numeric variable with resistance index value(s).

• sys_dia_ratio - Numeric variable with systolic/diastolic ratio value(s).

• tcd_mm - Numeric variable with transcerebellar diameter(s) in mm.

• par_occ_fiss_mm - Numeric variable with parietal-occipital fissure measurement(s) in mm.

• sylv_fiss_mm - Numeric variable with Sylvian fissure measurement(s) in mm.

• ant_hlv_mm - Numeric variable with anterior horn of lateral ventricle measurements(s) in mm.

• atr_phlv_mm - Numeric variable with atrium of posterior horn of lateral ventricle measurement(s) in mm.

• cist_mag_mm - Numeric variable with cisterna magna measurement(s) in mm.

Those functions are generated by the %gigs_ig_fet_acronym() macro.

See also

See the following function used internally by this function: gigs_validate_ig_fet, gigs_ig_fet_doppler_y2z, gigs_ig_fet_efw_y2z, gigs_ig_fet_gwg_y2z, and gigs_ig_fet_mu_sigma_y2z.

References

Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):869-79. doi: 10.1016/S0140-6736(14)61490-2

Stirnemann J, Villar J, Salomon LJ, Ohuma EO, Lamber A, Victoria CG et al. International Estimated Fetal Weight Standards of the INTERGROWTH-21st Project. Ultrasound Obstet Gynecol 2016, 49:478-486 doi: 10.1002/uog.17347

Papageorghiou AT, Ohuma EO, Gravett MG, Lamber A, Noble JA, Pang R et al. International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: prospective cohort study in eight countries. BMJ 2016, 355:i5662 doi: 10.1136/bmj.i5662

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Cheikh Ismail L, Bishop DC, Pang R, Ohuma EO, Kac G, Abrams B et al. Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352:i555 doi: 10.1136/bmj.i555

Drukker L, Staines-Urias E, Villar J, Barros FC, Carvalho M, Munim S et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project. Am J Obstet Gynecol 2021, 222(6):602.e1-602.e15 doi: 10.1016/j.ajog.2020.01.012

Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2021, 57(4):614-623 doi: 10.1002/uog.22017

Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B et al. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2020, 56(3):359-370 doi: 10.1002/uog.21990

Stirnemann J, Salomon LJ, Papageorghiou AT. INTERGROWTH-21st standards for Hadlock's estimation of fetal weight Ultrasound Obstet Gynecol 2020, 56(6):946-948 doi: 10.1002/uog.22000

Examples

1. Convert values to z-scores

data _null_;
  acronym = "acfga";

  do abdocirc_mm = 335 to 340;
    do gest_days = 265 to 270;
      value = gigs_ig_fet_value2zscore(abdocirc_mm,gest_days,acronym);
      put (_ALL_) (=);
    end;
    put;
  end;
run;

---

---

gigs_ig_fet_zscore2value() function

Convert z-scores to values in the INTERGROWTH-21^st Fetal standards

Syntax

function gigs_ig_fet_zscore2value(
  z
, x
, acronym $
);

---

Arguments

1. z - Numeric variable with z-scores to convert to values.

2. x - Numeric variable with x values. Elements should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 98 and 280 days for "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", and "tcdfga".
   • Between 154 and 280 days for "efwfga".
   • Between 112 and 294 days for "sfhfga".
   • Between 58 and 105 days for "crlfga".
   • Between 19 and 95 mm for "gafcrl".
   • Between 105 and 280 days for "gwgfga".
   • Between 168 and 280 days for "pifga", "rifga", and "sdrfga" (the INTERGROWTH-21^st Fetal Doppler standards).
   • Between 105 and 252 days for "poffga", "sffga", "avfga", and "pvfga" (the INTERGROWTH-21^st Fetal Brain Development standards).
   • Between 126 and 287 days for "hefwfga" (the INTERGROWTH-21^st standard for Hadlock-based estimated fetal weight).

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

   Numeric variable gest_days, crl_mm, or tcd_mm are standard-specific x variables.

3. acronym - Character variable denoting the INTERGROWTH-21^st Fetal Growth standard(s) in use. Each value should be one of:

   • "hcfga" (head circumference-for-GA)
   • "bpdfga" (biparietal diameter-for-GA)
   • "acfga" (abdominal circumference-for-GA)
   • "flfga" (femur length-for-GA)
   • "ofdfga" (occipito-frontal diameter-for-GA)
   • "efwfga" (estimated fetal weight-for-GA)
   • "sfhfga" (symphisis-fundal height-for-GA)
   • "crlfga" (crown-rump length-for-GA)
   • "gafcrl" (GA-for-crown-rump length)
   • "gwgfga" (gestational weight gain-for-GA)
   • "pifga" (pulsatility index-for-GA)
   • "rifga" (resistance index-for-GA)
   • "sdrfga" (systolic/diastolic ratio-for-GA)
   • "tcdfga" (transcerebellar diameter-for-GA)
   • "poffga" (parieto-occipital fissure-for-GA)
   • "sffga" (Sylvian fissure-for-GA)
   • "avfga" (anterior horn of lateral ventricle-for-GA)
   • "pvfga" (atrium of posterior horn of lateral ventricle-for-GA)
   • "cmfga" (cisterna magna-for-GA)
   • "hefwfga" (Hadlock esimated fetal weight-for-GA)

   If elements in acronym are not one of the above values, gigs will return missing value (.).

Returns

Numeric variable of expected measurements for each z-score.

Note

For each acronym from the list: "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", "efwfga", "sfhfga", "crlfga", "gafcrl", "gwgfga", "pifga", "rifga", "sdrfga", "tcdfga", "poffga", "hefwfga", "sffga", "avfga", "pvfga", and "cmfga" a counterpart "acronym function", which is a wrapper for the gigs_ig_fet_zscore2value, is generated. The "acronym function" has the following form:

gigs_ig_fet_<acronym>_zscore2value(z, x)

Complete list is:

gigs_ig_fet_hcfga_zscore2value(z, gest_days)

gigs_ig_fet_bpdfga_zscore2value(z, gest_days)

gigs_ig_fet_acfga_zscore2value(z, gest_days)

gigs_ig_fet_flfga_zscore2value(z, gest_days)

gigs_ig_fet_ofdfga_zscore2value(z, gest_days)

gigs_ig_fet_efwfga_zscore2value(z, gest_days)

gigs_ig_fet_hefwfga_zscore2value(z, gest_days)

gigs_ig_fet_sfhfga_zscore2value(z, gest_days)

gigs_ig_fet_crlfga_zscore2value(z, gest_days)

gigs_ig_fet_gafcrl_zscore2value(z, crl_mm)

gigs_ig_fet_gwgfga_zscore2value(z, gest_days)

gigs_ig_fet_pifga_zscore2value(z, gest_days)

gigs_ig_fet_rifga_zscore2value(z, gest_days)

gigs_ig_fet_sdrfga_zscore2value(z, gest_days)

gigs_ig_fet_tcdfga_zscore2value(z, gest_days)

gigs_ig_fet_gaftcd_zscore2value(z, tcd_mm)

gigs_ig_fet_poffga_zscore2value(z, gest_days)

gigs_ig_fet_sffga_zscore2value(z, gest_days)

gigs_ig_fet_avfga_zscore2value(z, gest_days)

gigs_ig_fet_pvfga_zscore2value(z, gest_days)

gigs_ig_fet_cmfga_zscore2value(z, gest_days)

Those functions are generated by the %gigs_ig_fet_acronym() macro.

See also

See the following function used internally by this function: gigs_validate_ig_fet, gigs_ig_fet_doppler_z2y, gigs_ig_fet_efw_z2y, gigs_ig_fet_gwg_z2y, and gigs_ig_fet_mu_sigma_z2y.

References

Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):869-79. doi: 10.1016/S0140-6736(14)61490-2

Stirnemann J, Villar J, Salomon LJ, Ohuma EO, Lamber A, Victoria CG et al. International Estimated Fetal Weight Standards of the INTERGROWTH-21st Project. Ultrasound Obstet Gynecol 2016, 49:478-486 doi: 10.1002/uog.17347

Papageorghiou AT, Ohuma EO, Gravett MG, Lamber A, Noble JA, Pang R et al. International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: prospective cohort study in eight countries. BMJ 2016, 355:i5662 doi: 10.1136/bmj.i5662

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Cheikh Ismail L, Bishop DC, Pang R, Ohuma EO, Kac G, Abrams B et al. Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352:i555 doi: 10.1136/bmj.i555

Drukker L, Staines-Urias E, Villar J, Barros FC, Carvalho M, Munim S et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project. Am J Obstet Gynecol 2021, 222(6):602.e1-602.e15 doi: 10.1016/j.ajog.2020.01.012

Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2021, 57(4):614-623 doi: 10.1002/uog.22017

Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B et al. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2020, 56(3):359-370 doi: 10.1002/uog.21990

Stirnemann J, Salomon LJ, Papageorghiou AT. INTERGROWTH-21st standards for Hadlock's estimation of fetal weight Ultrasound Obstet Gynecol 2020, 56(6):946-948 doi: 10.1002/uog.22000

Examples

1. Calculate value from z-scores

data _null_;
  acronym = "acfga";

  do z = -1 to 1;
    do x = 279 to 281;
      value = gigs_ig_fet_zscore2value(z,x,acronym);
      put (_ALL_) (=);
    end;
    put;
  end;
run;

---

---

gigs_ig_png_centile2value() function

Convert centiles to values in the INTERGROWTH-21^st Postnatal Growth Standards for preterm infants

Syntax

function gigs_ig_png_centile2value(
  p
, x
, sex $
, acronym $
); 

---

Arguments

1. p - Numeric variable with centiles to convert to values.

2. x - Numeric variable with x values. Elements of x or its standard-specific equivalents (pma_weeks, length_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 27 and 64 weeks for "wfa", "lfa", and "hcfa".
   • Between 35 and 65 cm for "wfl".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the INTERGROWTH-21^st Postnatal Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "lfa" (length-for-age)
   • "hcfa" (head circumference-for-age)
   • "wfl" (weight-for-length)

Returns

Numeric variable of expected measurements for each centile.

Note

For each acronym from the list: "wfa", "lfa", "hcfa", and "wfl" a counterpart "acronym function", which is a wrapper for the gigs_ig_png_centile2value, is generated. The "acronym function" has the following form:

gigs_ig_png_<acronym>_centile2value(p, x, sex)

Complete list is:

gigs_ig_png_wfa_centile2value(p, pma_weeks, sex)

gigs_ig_png_lfa_centile2value(p, pma_weeks, sex)

gigs_ig_png_hcfa_centile2value(p, pma_weeks, sex)

gigs_ig_png_wfl_centile2value(p, length_cm, sex)

Those functions are generated by the %gigs_ig_png_acronym() macro.

See also

The function internally use gigs_validate_ig_png, gigs_ig_png_equations, and SAS QUANTILE functions.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

Example

1. Convert centiles to values

data have;
  input p pma_weeks sex :$1.;
CARDS4;
0.25 54 M
0.50 55 F
0.75 56 M
;;;;
run;

data get;
  set have;
  acronym = "wfa";
  
  value = gigs_ig_png_centile2value(p, pma_weeks, sex, acronym);
run;

---

---

gigs_ig_png_value2centile() function

Convert values to centiles in the INTERGROWTH-21^st Postnatal Growth Standards for preterm infants

Syntax

function gigs_ig_png_value2centile(
  y
, x
, sex $
, acronym $
);

---

Arguments

1. y - Numeric variable with anthropometric measurement(s) to convert to centiles. Units depend on which acronym(s) are in use.

2. x - Numeric variable with x values. Elements of x or its standard-specific equivalents (pma_weeks, length_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 27 and 64 weeks for "wfa", "lfa", and "hcfa".
   • Between 35 and 65 cm for "wfl".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the INTERGROWTH-21^st Postnatal Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "lfa" (length-for-age)
   • "hcfa" (head circumference-for-age)
   • "wfl" (weight-for-length)

Returns

Numeric variable of centiles.

Note

For each acronym from the list: "wfa", "lfa", "hcfa", and "wfl" a counterpart "acronym function", which is a wrapper for the gigs_ig_png_value2zscore, is generated. The "acronym function" has the following form:

gigs_ig_png_<acronym>_value2zscore(y, x, sex)

Complete list is:

gigs_ig_png_wfa_value2zscore(weight_kg, pma_weeks, sex)

gigs_ig_png_lfa_value2zscore(length_cm, pma_weeks, sex)

gigs_ig_png_hcfa_value2zscore(headcirc_cm, pma_weeks, sex)

gigs_ig_png_wfl_value2zscore(weight_kg, length_cm, sex)

Parameters meaning:

• weight_kg - Numeric variable with weight measurement(s) in kg.
• pma_weeks - Numeric variable with post-menstrual age(s) in weeks. Values should be within the bounds defined in the documentation for x.
• length_cm - Numeric variable with recumbent length measurement(s) in cm. This argument can be either an x variable when using the length-for-age standard ("lfa"), or a y variable when using the weight-for-length ("wfl") standard.
• headcirc_cm - Numeric variable with head circumference measurement(s) in cm.

Those functions are generated by the %gigs_ig_png_acronym() macro.

See also

The function internally use gigs_validate_ig_png, and gigs_ig_png_equations functions.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

Examples

1. Get centiles for values

data have;
  inpout weight_kg pma_weeks sex :$1.;
CARDS4;
5.79 54 M
5.92 55 F
7.25 56 M
;;;;
run;

data get;
  set have;
  acronym = "wfa";
  
  centiles = gigs_ig_png_value2centile(weight_kg, pma_weeks, sex, acronym);
run;

---

---

gigs_ig_png_value2zscore() function

Convert values to z-scores in the INTERGROWTH-21^st Postnatal Growth Standards for preterm infants

Syntax

function gigs_ig_png_value2zscore(
  y
, x
, sex $
, acronym $
);

---

Arguments

1. y - Numeric variable with anthropometric measurement(s) to convert to z-scores. Units depend on which acronym(s) are in use.

2. x - Numeric variable with x values. Elements of x or its standard-specific equivalents (pma_weeks, length_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 27 and 64 weeks for "wfa", "lfa", and "hcfa".
   • Between 35 and 65 cm for "wfl".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the INTERGROWTH-21^st Postnatal Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "lfa" (length-for-age)
   • "hcfa" (head circumference-for-age)
   • "wfl" (weight-for-length)

Returns

Numeric variable of z-scores for each measurement.

Note

For each acronym from the list: "wfa", "lfa", "hcfa", and "wfl" a counterpart "acronym function", which is a wrapper for the gigs_ig_png_value2zscore, is generated. The "acronym function" has the following form:

gigs_ig_png_<acronym>_value2zscore(y, x, sex)

Complete list is:

gigs_ig_png_wfa_value2zscore(weight_kg, pma_weeks, sex)

gigs_ig_png_lfa_value2zscore(length_cm, pma_weeks, sex)

gigs_ig_png_hcfa_value2zscore(headcirc_cm, pma_weeks, sex)

gigs_ig_png_wfl_value2zscore(weight_kg, length_cm, sex)

Parameters meaning:

• weight_kg - Numeric variable with weight measurement(s) in kg.
• pma_weeks - Numeric variable with post-menstrual age(s) in weeks. Values should be within the bounds defined in the documentation for x.
• length_cm - Numeric variable with recumbent length measurement(s) in cm. This argument can be either an x variable when using the length-for-age standard ("lfa"), or a y variable when using the weight-for-length ("wfl") standard.
• headcirc_cm - Numeric variable with head circumference measurement(s) in cm.

Those functions are generated by the %gigs_ig_png_acronym() macro.

See also

The function internally use gigs_validate_ig_png, and gigs_ig_png_equations functions.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

Examples

1. Get z-score for values

data have;
  inpout weight_kg pma_weeks sex :$1.;
CARDS4;
5.79 54 M
5.92 55 F
7.25 56 M
;;;;
run;

data get;
  set have;
  acronym = "wfa";
  
  zscore = gigs_ig_png_value2zscore(weight_kg, pma_weeks, sex, acronym);
run;

---

---

gigs_ig_png_zscore2value() function

Convert z-scores to values in the INTERGROWTH-21^st Postnatal Growth Standards for preterm infants

Syntax

function gigs_ig_png_zscore2value(
  z
, x
, sex $
, acronym $
);

---

Arguments

1. z - Numeric variable with z-scores to convert to values.

2. x - Numeric variable with x values. Elements of x or its standard-specific equivalents (pma_weeks, length_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 27 and 64 weeks for "wfa", "lfa", and "hcfa".
   • Between 35 and 65 cm for "wfl".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the INTERGROWTH-21^st Postnatal Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "lfa" (length-for-age)
   • "hcfa" (head circumference-for-age)
   • "wfl" (weight-for-length)

Returns

Numeric variable of expected measurements for each z-score.

Note

For each acronym from the list: "wfa", "lfa", "hcfa", and "wfl" a counterpart "acronym function", which is a wrapper for the gigs_ig_png_zscore2value, is generated. The "acronym function" has the following form:

gigs_ig_png_<acronym>_zscore2value(z, x, sex)

Complete list is:

gigs_ig_png_wfa_zscore2value(z, pma_weeks, sex)

gigs_ig_png_lfa_zscore2value(z, pma_weeks, sex)

gigs_ig_png_hcfa_zscore2value(z, pma_weeks, sex)

gigs_ig_png_wfl_zscore2value(z, length_cm, sex)

Those functions are generated by the %gigs_ig_png_acronym() macro.

See also

The function internally use gigs_validate_ig_png, and gigs_ig_png_equations functions.

References

Villar J, Giuliani F, Bhutta ZA, Bertino E, Ohuma EO, Ismail LC et al. Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21st Project. Lancet Glob Health 2015, 3(11):e681-e691. doi: 10.1016/S2214-109X(15)00163-1

Example

1. Convert z-scores to values

data have;
  input z pma_weeks sex :$1.;
CARDS4;
-0.6745 54 M
+0.0000 55 F
+0.6745 56 M
;;;;
run;

data get;
  set have;
  acronym = "wfa";
  
  value = gigs_ig_png_zscore2value(z, pma_weeks, sex, acronym);
run;

---

---

gigs_who_gs_value2zscore() function

Convert values to z-scores in the WHO Child Growth Standards

Syntax

function gigs_who_gs_value2zscore(
  y
, x
, sex $
, acronym $
);  

---

Arguments

1. y - Numeric variable with anthropometric measurement(s) to convert to z-scores. Units depend on which acronym(s) are in use.

2. x - Numeric variable with x values. Elements in x or its standard-specific equivalents (age_days, length_cm, and height_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 0 and 1856 days for "wfa", "bfa", "lhfa", and "hcfa".
   • Between 45 and 110 cm for "wfl".
   • Between 65 and 120 cm for "wfh".
   • Between 91 and 1856 days for "acfa", "ssfa", "tsfa".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the WHO Child Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "bfa" (BMI-for-age)
   • "lhfa" (length/height-for-age)
   • "wfl" (weight-for-length)
   • "wfh" (weight-for-height)
   • "hcfa" (head circumference-for-age)
   • "acfa" (arm circumference-for-age)
   • "ssfa" (subscapular skinfold-for-age)
   • "tsfa" (triceps skinfold-for-age)

Returns

Numeric variable of z-scores for each measurement.

Note

For each acronym from the list: "wfa", "bfa", "lhfa", "wfl", "wfh", "hcfa", "acfa", "ssfa", and "tsfa" a counterpart "acronym function", which is a wrapper for the gigs_who_gs_value2zscore, is generated. The "acronym function" has the following form:

gigs_who_gs_<acronym>_value2zscore(y, x, sex)

Complete list is:

gigs_who_gs_wfa_value2zscore(weight_kg, age_days, sex)

gigs_who_gs_bfa_value2zscore(bmi, age_days, sex)

gigs_who_gs_lhfa_value2zscore(lenht_cm, age_days, sex)

gigs_who_gs_wfl_value2zscore(weight_kg, length_cm, sex)

gigs_who_gs_wfh_value2zscore(weight_kg, height_cm, sex)

gigs_who_gs_hcfa_value2zscore(headcirc_cm, age_days, sex)

gigs_who_gs_acfa_value2zscore(armcirc_cm, age_days, sex)

gigs_who_gs_ssfa_value2zscore(subscap_sf_mm, age_days, sex)

gigs_who_gs_tsfa_value2zscore(triceps_sf_mm, age_days, sex)

Parameters meaning:

• weight_kg - Numeric variable with weight measurement(s) in kg.
• bmi - Numeric variable with body mass index measurement(s) in kg/m².
• lenht_cm - Numeric variable with length/height measurement(s) in cm.
• headcirc_cm - Numeric variable with head circumference measurement(s) in cm.
• armcirc_cm - Numeric variable with arm circumference measurement(s) in cm.
• subscap_sf_mm - Numeric variable with subscapular skinfold measurement(s) in mm.
• triceps_sf_mm - Numeric variable with triceps skinfold measurement(s) in mm.

Those functions are generated by the %gigs_who_gs_acronym() macro.

See also

The function internally use gigs_validate_who_gs, gigs_who_gs_lms, and gigs_v_from_lms functions.

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Cole TJ. The LMS method for constructing normalized growth standards Eur J Clin Nutr. 1990, 44(1):45-60. PMID: 2354692

Examples

1. Convert values to z-scores

data have;
  input weight_kg age_days sex :$1.;
CARDS4;
10.1 504 M
10.2 505 F
10.3 506 M
;;;;
run;

data get;
  set have;
  acronym = "wfa";
  
  zscore = gigs_who_gs_value2zscore(
    weight_kg
  , age_days 
  , sex
  , acronym
  );
run;

---

---

gigs_who_gs_zscore2value() function

Convert z-scores to values in the WHO Child Growth Standards

Synatx

function gigs_who_gs_zscore2value(
  z
, x
, sex $
, acronym $
);

---

Arguments

1. z - Numeric variable with z-scores to convert to values.

2. x - Numeric variable with x values. Elements in x or its standard-specific equivalents (age_days, length_cm, and height_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 0 and 1856 days for "wfa", "bfa", "lhfa", and "hcfa".
   • Between 45 and 110 cm for "wfl".
   • Between 65 and 120 cm for "wfh".
   • Between 91 and 1856 days for "acfa", "ssfa", "tsfa".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the WHO Child Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "bfa" (BMI-for-age)
   • "lhfa" (length/height-for-age)
   • "wfl" (weight-for-length)
   • "wfh" (weight-for-height)
   • "hcfa" (head circumference-for-age)
   • "acfa" (arm circumference-for-age)
   • "ssfa" (subscapular skinfold-for-age)
   • "tsfa" (triceps skinfold-for-age)

Returns

Numeric variable of expected measurements for each z-score.

Note

For each acronym from the list: "wfa", "bfa", "lhfa", "wfl", "wfh", "hcfa", "acfa", "ssfa", and "tsfa" a counterpart "acronym function", which is a wrapper for the gigs_who_gs_zscore2value, is generated. The "acronym function" has the following form:

gigs_who_gs_<acronym>_zscore2value(z, x, sex)

Complete list is:

gigs_who_gs_wfa_zscore2value(z, age_days, sex)

gigs_who_gs_bfa_zscore2value(z, age_days, sex)

gigs_who_gs_lhfa_zscore2value(z, age_days, sex)

gigs_who_gs_wfl_zscore2value(z, length_cm, sex)

gigs_who_gs_wfh_zscore2value(z, height_cm, sex)

gigs_who_gs_hcfa_zscore2value(z, age_days, sex)

gigs_who_gs_acfa_zscore2value(z, age_days, sex)

gigs_who_gs_ssfa_zscore2value(z, age_days, sex)

gigs_who_gs_tsfa_zscore2value(z, age_days, sex)

Those functions are generated by the %gigs_who_gs_acronym() macro.

See also

The function internally use gigs_validate_who_gs, gigs_who_gs_lms, and gigs_v_from_lms functions.

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Cole TJ. The LMS method for constructing normalized growth standards Eur J Clin Nutr. 1990, 44(1):45-60. PMID: 2354692

Examples

1. Convert z-scores to values

data _null_;
  acronym = "wfa";

  do z = -1 to 1;
    do age_days = 500 to 502;
      do sex = "M", "F", "M";
        value = gigs_who_gs_zscore2value(z, age_days, sex, acronym);
        put (_ALL_) (=);
      end;
      put;
    end;
  end;
run;

---

---

gigs_ig_fet_centile2value() function

Convert centiles to values in the INTERGROWTH-21^st Fetal standards

Syntax

function gigs_ig_fet_centile2value(
  p
, x
, acronym $
);

---

Arguments

1. p - Numeric variable with centiles to convert to values. For p, if an element of p is not between 0 and 1, gigs produce missing value (.).

2. x - Numeric variable with x values. Elements should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 98 and 280 days for "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", and "tcdfga".
   • Between 154 and 280 days for "efwfga".
   • Between 112 and 294 days for "sfhfga".
   • Between 58 and 105 days for "crlfga".
   • Between 19 and 95 mm for "gafcrl".
   • Between 105 and 280 days for "gwgfga".
   • Between 168 and 280 days for "pifga", "rifga", and "sdrfga" (the INTERGROWTH-21^st Fetal Doppler standards).
   • Between 105 and 252 days for "poffga", "sffga", "avfga", and "pvfga" (the INTERGROWTH-21^st Fetal Brain Development standards).
   • Between 126 and 287 days for "hefwfga" (the INTERGROWTH-21^st standard for Hadlock-based estimated fetal weight).

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

   Numeric variable gest_days, crl_mm, or tcd_mm are standard-specific x variables.

3. acronym - Character variable denoting the INTERGROWTH-21^st Fetal Growth standard(s) in use. Each value should be one of:

   • "hcfga" (head circumference-for-GA)
   • "bpdfga" (biparietal diameter-for-GA)
   • "acfga" (abdominal circumference-for-GA)
   • "flfga" (femur length-for-GA)
   • "ofdfga" (occipito-frontal diameter-for-GA)
   • "efwfga" (estimated fetal weight-for-GA)
   • "sfhfga" (symphisis-fundal height-for-GA)
   • "crlfga" (crown-rump length-for-GA)
   • "gafcrl" (GA-for-crown-rump length)
   • "gwgfga" (gestational weight gain-for-GA)
   • "pifga" (pulsatility index-for-GA)
   • "rifga" (resistance index-for-GA)
   • "sdrfga" (systolic/diastolic ratio-for-GA)
   • "tcdfga" (transcerebellar diameter-for-GA)
   • "poffga" (parieto-occipital fissure-for-GA)
   • "sffga" (Sylvian fissure-for-GA)
   • "avfga" (anterior horn of lateral ventricle-for-GA)
   • "pvfga" (atrium of posterior horn of lateral ventricle-for-GA)
   • "cmfga" (cisterna magna-for-GA)
   • "hefwfga" (Hadlock esimated fetal weight-for-GA)

   If elements in acronym are not one of the above values, gigs will return missing value (.).

Returns

Numeric variable of expected measurements for each centile.

Note

For each acronym from the list: "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", "efwfga", "sfhfga", "crlfga", "gafcrl", "gwgfga", "pifga", "rifga", "sdrfga", "tcdfga", "poffga", "hefwfga", "sffga", "avfga", "pvfga", and "cmfga" a counterpart "acronym function", which is a wrapper for the gigs_ig_fet_centile2value, is generated. The "acronym function" has the following form:

gigs_ig_fet_<acronym>_centile2value(p, x)

Complete list is:

gigs_ig_fet_hcfga_centile2value(p, gest_days)

gigs_ig_fet_bpdfga_centile2value(p, gest_days)

gigs_ig_fet_acfga_centile2value(p, gest_days)

gigs_ig_fet_flfga_centile2value(p, gest_days)

gigs_ig_fet_ofdfga_centile2value(p, gest_days)

gigs_ig_fet_efwfga_centile2value(p, gest_days)

gigs_ig_fet_hefwfga_centile2value(p, gest_days)

gigs_ig_fet_sfhfga_centile2value(p, gest_days)

gigs_ig_fet_crlfga_centile2value(p, gest_days)

gigs_ig_fet_gafcrl_centile2value(p, crl_mm)

gigs_ig_fet_gwgfga_centile2value(p, gest_days)

gigs_ig_fet_pifga_centile2value(p, gest_days)

gigs_ig_fet_rifga_centile2value(p, gest_days)

gigs_ig_fet_sdrfga_centile2value(p, gest_days)

gigs_ig_fet_tcdfga_centile2value(p, gest_days)

gigs_ig_fet_gaftcd_centile2value(p, tcd_mm)

gigs_ig_fet_poffga_centile2value(p, gest_days)

gigs_ig_fet_sffga_centile2value(p, gest_days)

gigs_ig_fet_avfga_centile2value(p, gest_days)

gigs_ig_fet_pvfga_centile2value(p, gest_days)

gigs_ig_fet_cmfga_centile2value(p, gest_days)

Those functions are generated by the %gigs_ig_fet_acronym() macro.

See also

See the following function used internally by this function: gigs_ig_fet_zscore2value and SAS QUANTILE.

References

Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):869-79. doi: 10.1016/S0140-6736(14)61490-2

Stirnemann J, Villar J, Salomon LJ, Ohuma EO, Lamber A, Victoria CG et al. International Estimated Fetal Weight Standards of the INTERGROWTH-21st Project. Ultrasound Obstet Gynecol 2016, 49:478-486 doi: 10.1002/uog.17347

Papageorghiou AT, Ohuma EO, Gravett MG, Lamber A, Noble JA, Pang R et al. International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: prospective cohort study in eight countries. BMJ 2016, 355:i5662 doi: 10.1136/bmj.i5662

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Cheikh Ismail L, Bishop DC, Pang R, Ohuma EO, Kac G, Abrams B et al. Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352:i555 doi: 10.1136/bmj.i555

Drukker L, Staines-Urias E, Villar J, Barros FC, Carvalho M, Munim S et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project. Am J Obstet Gynecol 2021, 222(6):602.e1-602.e15 doi: 10.1016/j.ajog.2020.01.012

Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2021, 57(4):614-623 doi: 10.1002/uog.22017

Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B et al. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2020, 56(3):359-370 doi: 10.1002/uog.21990

Stirnemann J, Salomon LJ, Papageorghiou AT. INTERGROWTH-21st standards for Hadlock's estimation of fetal weight Ultrasound Obstet Gynecol 2020, 56(6):946-948 doi: 10.1002/uog.22000

Examples

1. Calculate value from centiles

data _null_;
  acronym = "hcfga";

  do p = 0.25, 0.5, 0.75;
    do x = 279 to 281;
      value = gigs_ig_fet_centile2value(p,x,acronym);
      put (_ALL_) (=);
    end;
    put;
  end;
run;

---

---

gigs_ig_fet_value2centile() function

Convert values to centiles in the INTERGROWTH-21^st Fetal Growth standards

Syntax

function gigs_ig_fet_value2centile(
  y
, x
, acronym $
);

---

Arguments

1. y - Numeric variable with values to convert to z-scores/centiles.

2. x - Numeric variable with x values. Elements should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 98 and 280 days for "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", and "tcdfga".
   • Between 154 and 280 days for "efwfga".
   • Between 112 and 294 days for "sfhfga".
   • Between 58 and 105 days for "crlfga".
   • Between 19 and 95 mm for "gafcrl".
   • Between 105 and 280 days for "gwgfga".
   • Between 168 and 280 days for "pifga", "rifga", and "sdrfga" (the INTERGROWTH-21^st Fetal Doppler standards).
   • Between 105 and 252 days for "poffga", "sffga", "avfga", and "pvfga" (the INTERGROWTH-21^st Fetal Brain Development standards).
   • Between 126 and 287 days for "hefwfga" (the INTERGROWTH-21^st standard for Hadlock-based estimated fetal weight).

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

   Numeric variable gest_days, crl_mm, or tcd_mm are standard-specific x variables.

3. acronym - Character variable denoting the INTERGROWTH-21^st Fetal Growth standard(s) in use. Each value should be one of:

   • "hcfga" (head circumference-for-GA)
   • "bpdfga" (biparietal diameter-for-GA)
   • "acfga" (abdominal circumference-for-GA)
   • "flfga" (femur length-for-GA)
   • "ofdfga" (occipito-frontal diameter-for-GA)
   • "efwfga" (estimated fetal weight-for-GA)
   • "sfhfga" (symphisis-fundal height-for-GA)
   • "crlfga" (crown-rump length-for-GA)
   • "gafcrl" (GA-for-crown-rump length)
   • "gwgfga" (gestational weight gain-for-GA)
   • "pifga" (pulsatility index-for-GA)
   • "rifga" (resistance index-for-GA)
   • "sdrfga" (systolic/diastolic ratio-for-GA)
   • "tcdfga" (transcerebellar diameter-for-GA)
   • "poffga" (parieto-occipital fissure-for-GA)
   • "sffga" (Sylvian fissure-for-GA)
   • "avfga" (anterior horn of lateral ventricle-for-GA)
   • "pvfga" (atrium of posterior horn of lateral ventricle-for-GA)
   • "cmfga" (cisterna magna-for-GA)
   • "hefwfga" (Hadlock esimated fetal weight-for-GA)

   If elements in acronym are not one of the above values, gigs will return missing value (.).

Returns

Numeric variable of expected z-scores for each measurement.

Note

For each acronym from the list: "hcfga", "bpdfga", "acfga", "flfga", "ofdfga", "efwfga", "sfhfga", "crlfga", "gafcrl", "gwgfga", "pifga", "rifga", "sdrfga", "tcdfga", "poffga", "hefwfga", "sffga", "avfga", "pvfga", and "cmfga" a counterpart "acronym function", which is a wrapper for the gigs_ig_fet_value2centile, is generated. The "acronym function" has the following form:

gigs_ig_fet_<acronym>_value2centile(y, x)

Complete list is:

gigs_ig_fet_hcfga_value2centile(headcirc_mm, gest_days)

gigs_ig_fet_bpdfga_value2centile(bpd_mm, gest_days)

gigs_ig_fet_acfga_value2centile(abdocirc_mm, gest_days)

gigs_ig_fet_flfga_value2centile(femurlen_mm, gest_days)

gigs_ig_fet_ofdfga_value2centile(ofd_mm, gest_days)

gigs_ig_fet_efwfga_value2centile(efw_g, gest_days)

gigs_ig_fet_hefwfga_value2centile(hadlock_efw_g, gest_days)

gigs_ig_fet_sfhfga_value2centile(sfh_cm, gest_days)

gigs_ig_fet_crlfga_value2centile(crl_mm, gest_days)

gigs_ig_fet_gafcrl_value2centile(gest_days, crl_mm)

gigs_ig_fet_gwgfga_value2centile(gest_wt_gain_kg, gest_days)

gigs_ig_fet_pifga_value2centile(puls_idx, gest_days)

gigs_ig_fet_rifga_value2centile(resist_idx, gest_days)

gigs_ig_fet_sdrfga_value2centile(sys_dia_ratio, gest_days)

gigs_ig_fet_tcdfga_value2centile(tcd_mm, gest_days)

gigs_ig_fet_gaftcd_value2centile(gest_days, tcd_mm)

gigs_ig_fet_poffga_value2centile(par_occ_fiss_mm, gest_days)

gigs_ig_fet_sffga_value2centile(sylv_fiss_mm, gest_days)

gigs_ig_fet_avfga_value2centile(ant_hlv_mm, gest_days)

gigs_ig_fet_pvfga_value2centile(atr_phlv_mm, gest_days)

gigs_ig_fet_cmfga_value2centile(cist_mag_mm, gest_days)

Parameters meaning:

• gest_days - Numeric variable that is usually used as the x variable, but can also be a y variable for the "gafcrl" and "gaftcd" standards.

• headcirc_mm - Numeric variable with head circumference measurements in mm.

• bpd_mm - Numeric variable with biparietal diameter measurement(s) in mm.

• abdocirc_mm - Numeric variable with abdominal circumference measurement(s) in mm.

• femurlen_mm - Numeric variable with femur length(s) in mm.

• ofd_mm - Numeric variable with in occipito-frontal diameter(s) in mm.

• efw_g - Numeric variable with estimated fetal weight(s) in g.

• hadlock_efw_g - Numeric variable with estimated fetal weight(s) in g.

• sfh_cm - Numeric variable with symphisis-fundal height(s) in mm.

• crl_mm - Numeric variable with crown-rump length(s) in mm.

• gest_wt_gain_kg - Numeric variable with gestational weight gain(s)/loss(es) in kg.

• puls_idx - Numeric variable with pulsatility index value(s).

• resist_idx - Numeric variable with resistance index value(s).

• sys_dia_ratio - Numeric variable with systolic/diastolic ratio value(s).

• tcd_mm - Numeric variable with transcerebellar diameter(s) in mm.

• par_occ_fiss_mm - Numeric variable with parietal-occipital fissure measurement(s) in mm.

• sylv_fiss_mm - Numeric variable with Sylvian fissure measurement(s) in mm.

• ant_hlv_mm - Numeric variable with anterior horn of lateral ventricle measurements(s) in mm.

• atr_phlv_mm - Numeric variable with atrium of posterior horn of lateral ventricle measurement(s) in mm.

• cist_mag_mm - Numeric variable with cisterna magna measurement(s) in mm.

Those functions are generated by the %gigs_ig_fet_acronym() macro.

See also

See the following function used internally by this function: gigs_ig_fet_value2zscore and SAS CDF.

References

Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A et al. International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):869-79. doi: 10.1016/S0140-6736(14)61490-2

Stirnemann J, Villar J, Salomon LJ, Ohuma EO, Lamber A, Victoria CG et al. International Estimated Fetal Weight Standards of the INTERGROWTH-21st Project. Ultrasound Obstet Gynecol 2016, 49:478-486 doi: 10.1002/uog.17347

Papageorghiou AT, Ohuma EO, Gravett MG, Lamber A, Noble JA, Pang R et al. International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: prospective cohort study in eight countries. BMJ 2016, 355:i5662 doi: 10.1136/bmj.i5662

Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48 doi: 10.1002/uog.13448

Cheikh Ismail L, Bishop DC, Pang R, Ohuma EO, Kac G, Abrams B et al. Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352:i555 doi: 10.1136/bmj.i555

Drukker L, Staines-Urias E, Villar J, Barros FC, Carvalho M, Munim S et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project. Am J Obstet Gynecol 2021, 222(6):602.e1-602.e15 doi: 10.1016/j.ajog.2020.01.012

Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2021, 57(4):614-623 doi: 10.1002/uog.22017

Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B et al. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project Ultrasound Obstet Gynecol 2020, 56(3):359-370 doi: 10.1002/uog.21990

Stirnemann J, Salomon LJ, Papageorghiou AT. INTERGROWTH-21st standards for Hadlock's estimation of fetal weight Ultrasound Obstet Gynecol 2020, 56(6):946-948 doi: 10.1002/uog.22000

Examples

1. Convert values to centiles

data _null_;
  acronym = "acfga";

  do abdocirc_mm = 335 to 340;
    do gest_days = 265 to 270;
      value = gigs_ig_fet_value2centile(abdocirc_mm,gest_days,acronym);
      put (_ALL_) (=);
    end;
    put;
  end;
run;

---

---

gigs_ig_nbs_centile2value() function

Convert centiles to values in the INTERGROWTH-21^st Newborn Size Standards

Syntax

function gigs_ig_nbs_centile2value(
  p
, gest_days
, sex $
, acronym $
);

---

Arguments

1. p - Numeric variable with centiles to convert to values. For p, if an element of p is not between 0 and 1, gigs will produce missing value (.).

2. gest_days - Numeric variable with gestational ages in days. Elements should be between certain values depending on the Newborn Size standard in use (defined by acronym). These are:

   • Between 168 and 300 days for "wfga", "lfga", "hcfga", and "wlrfga".
   • Between 154 and 280 days for "fmfga", "bfpfga", and "ffmfga". By default, gigs will ignore gest_days that are out of bounds for the growth standard and return missing value (.).

3. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

4. acronym - Character variable denoting the INTERGROWTH-21^st Newborn Size standard to use for each observation. Each element should be one of:

   • "wfga" (weight-for-GA)
   • "lfga" (length-for-GA)
   • "hcfga" (head circumference-for-GA)
   • "wlrfga" (weight/length ratio-for-GA)
   • "fmfga" (fat mass-for-GA)
   • "bfpfga" (body fat %-for-GA)
   • "ffmfga" (fat-free mass-for-GA) This argument is not case-sensitive.

Returns

Numeric variable of expected measurements for each centile.

Note

For each acronym from the list: "wfga", "lfga", "hcfga", "wlrfga", "fmfga", "bfpfga", and "ffmfga"
a counterpart "acronym function", which is a wrapper for the gigs_ig_nbs_centile2value, is generated. The "acronym function" has the following form:

gigs_ig_nbs_<acronym>_centile2value(p, gest_days, sex)

Complete list is:

gigs_ig_nbs_wfga_centile2value(p, gest_days, sex)

gigs_ig_nbs_lfga_centile2value(p, gest_days, sex)

gigs_ig_nbs_hcfga_centile2value(p, gest_days, sex)

gigs_ig_nbs_wlrfga_centile2value(p, gest_days, sex)

gigs_ig_nbs_fmfga_centile2value(p, gest_days, sex)

gigs_ig_nbs_bfpfga_centile2value(p, gest_days, sex)

gigs_ig_nbs_ffmfga_centile2value(p, gest_days, sex)

Those functions are generated by the %gigs_ig_nbs_acronym() macro.

See also

The function internally utilizes the following functions: gigs_validate_ig_nbs, gigs_ig_nbs_msnt_p2v, gigs_ig_vpns_zscore2value, gigs_ig_nbs_wlrfga_p2v, and gigs_ig_nbs_bodycomp_p2v.

References

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH et al. INTERGROWTH-21st very preterm size at birth reference charts. Lancet 2016, 387(10021):844-45. doi: 10.1016/S0140-6736(16)00384-6

Villar J, Puglia FA, Fenton TR, Ismal LC, Staines-Urias E, Giuliani F, et al. Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project. Pediatric Research 2017, 82:305-316. doi: 10.1038/pr.2017.52

---

---

gigs_ig_nbs_value2centile() function

Convert values to centiles in the INTERGROWTH-21^st Newborn Size Standards

Syntax

  function gigs_ig_nbs_value2centile(
    y 
  , gest_days 
  , sex $
  , acronym $ 
  );

---

Arguments

1. y - Numeric variable with measurements to convert to centiles.

2. gest_days - Numeric variable with gestational ages in days. Elements should be between certain values depending on the Newborn Size standard in use (defined by acronym). These are:

   • Between 168 and 300 days for "wfga", "lfga", "hcfga", and "wlrfga".
   • Between 154 and 280 days for "fmfga", "bfpfga", and "ffmfga". By default, gigs will ignore gest_days that are out of bounds for the growth standard and return missing value (.).

3. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

4. acronym - Character variable denoting the INTERGROWTH-21^st Newborn Size standard to use for each observation. Each element should be one of:

   • "wfga" (weight-for-GA)
   • "lfga" (length-for-GA)
   • "hcfga" (head circumference-for-GA)
   • "wlrfga" (weight/length ratio-for-GA)
   • "fmfga" (fat mass-for-GA)
   • "bfpfga" (body fat %-for-GA)
   • "ffmfga" (fat-free mass-for-GA) This argument is not case-sensitive.

Returns

Numeric variable of expected centiles for each measurement.

Note

For each acronym from the list: "wfga", "lfga", "hcfga", "wlrfga", "fmfga", "bfpfga", and "ffmfga"
a counterpart "acronym function", which is a wrapper for the gigs_ig_nbs_value2centile, is generated. The "acronym function" has the following form:

gigs_ig_nbs_<acronym>_value2centile(y, gest_days, sex)

Complete list is:

gigs_ig_nbs_wfga_value2centile(weight_kg, gest_days, sex)

gigs_ig_nbs_lfga_value2centile(length_cm, gest_days, sex)

gigs_ig_nbs_hcfga_value2centile(headcirc_cm, gest_days, sex)

gigs_ig_nbs_wlrfga_value2centile(wei_len_ratio, gest_days, sex)

gigs_ig_nbs_fmfga_value2centile(fat_mass_g, gest_days, sex)

gigs_ig_nbs_bfpfga_value2centile(body_fat_perc, gest_days, sex)

gigs_ig_nbs_ffmfga_value2centile(fatfree_mass_g, gest_days, sex

Parameters meaning:

• weight_kg - Numeric variable with birth weight(s) in kg.
• length_cm - Numeric variable with birth length(s) in cm.
• headcirc_cm - Numeric variable with birth head circumference(s) in cm.
• wei_len_ratio - Numeric variable with weight-length ratio(s) in kg per m.
• fat_mass_g - Numeric variable with fat mass(es) in g.
• body_fat_perc - Numeric variable with body fat percentage(s).
• fatfree_mass_g - Numeric variable with fat-free mass(es) in g.

Those functions are generated by the %gigs_ig_nbs_acronym() macro.

See also

The function internally utilizes the following functions: gigs_validate_ig_nbs, gigs_ig_nbs_msnt, gamlss_pST3, gigs_ig_vpns_value2zscore, gigs_ig_nbs_wlr, gigs_ig_nbs_bodycomp, and SAS CDF and PDF.

References

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH et al. INTERGROWTH-21st very preterm size at birth reference charts. Lancet 2016, 387(10021):844-45. doi: 10.1016/S0140-6736(16)00384-6

Villar J, Puglia FA, Fenton TR, Ismal LC, Staines-Urias E, Giuliani F, et al. Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project. Pediatric Research 2017, 82:305-316. doi: 10.1038/pr.2017.52

Examples

1. Convert values to z-scores

data have;
  input y gest_days sex :$1. acronym :$6.;
CARDS4;
2.90  274 F wfga
3.17  275 F wfga
3.46  276 F wfga
48.84 280 M lfga
;;;;
run;

data get;
  set have;
  
  centile=gigs_ig_nbs_value2centile(
    y
  , gest_days
  , sex
  , acronym
  );
run;

2. Use of "acronym function"

data get_lfga;
  length_cm = 48.84;
  gest_days = 280;
  sex = "M";

  centile = gigs_ig_nbs_lfga_value2centile(
    length_cm
  , gest_days
  , sex
);
run;

---

---

gigs_who_gs_centile2value() function

Convert centiles to values in the WHO Child Growth Standards

Synatx

function gigs_who_gs_centile2value(
  p
, x
, sex $
, acronym $
);

---

Arguments

1. p - Numeric variable with centiles to convert to values. For p, if an element of p is not between 0 and 1, gigs will return missing value (.).

2. x - Numeric variable with x values. Elements in x or its standard-specific equivalents (age_days, length_cm, and height_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 0 and 1856 days for "wfa", "bfa", "lhfa", and "hcfa".
   • Between 45 and 110 cm for "wfl".
   • Between 65 and 120 cm for "wfh".
   • Between 91 and 1856 days for "acfa", "ssfa", "tsfa".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the WHO Child Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "bfa" (BMI-for-age)
   • "lhfa" (length/height-for-age)
   • "wfl" (weight-for-length)
   • "wfh" (weight-for-height)
   • "hcfa" (head circumference-for-age)
   • "acfa" (arm circumference-for-age)
   • "ssfa" (subscapular skinfold-for-age)
   • "tsfa" (triceps skinfold-for-age)

Returns

Numeric variable of expected measurements for each centile.

Note

For each acronym from the list: "wfa", "bfa", "lhfa", "wfl", "wfh", "hcfa", "acfa", "ssfa", and "tsfa" a counterpart "acronym function", which is a wrapper for the gigs_who_gs_centile2value, is generated. The "acronym function" has the following form:

gigs_who_gs_<acronym>_centile2value(p, x, sex)

Complete list is:

gigs_who_gs_wfa_centile2value(p, age_days, sex)

gigs_who_gs_bfa_centile2value(p, age_days, sex)

gigs_who_gs_lhfa_centile2value(p, age_days, sex)

gigs_who_gs_wfl_centile2value(p, length_cm, sex)

gigs_who_gs_wfh_centile2value(p, height_cm, sex)

gigs_who_gs_hcfa_centile2value(p, age_days, sex)

gigs_who_gs_acfa_centilevalue(p, age_days, sex)

gigs_who_gs_ssfa_centilevalue(p, age_days, sex)

gigs_who_gs_tsfa_centilevalue(p, age_days, sex)

Those functions are generated by the %gigs_who_gs_acronym() macro.

See also

The function internally use gigs_who_gs_zscore2value, and SAS QUANTILE functions.

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Cole TJ. The LMS method for constructing normalized growth standards Eur J Clin Nutr. 1990, 44(1):45-60. PMID: 2354692

Examples

1. Convert centiles to values

data _null_;
  acronym = "wfa";

  do p = 0.25, 0.5, 0.75;
    do age_days = 500 to 502;
      do sex = "M", "F", "M";
        value = gigs_who_gs_centile2value(p, age_days, sex, acronym);
        put (_ALL_) (=);
      end;
      put;
    end;
  end;
run;

---

---

gigs_who_gs_value2centile() function

Convert values to centiles in the WHO Child Growth Standards

Syntax

function gigs_who_gs_value2centile(
  y
, x
, sex $
, acronym $
);

---

Arguments

1. y - Numeric variable with anthropometric measurement(s) to convert to centiles. Units depend on which acronym(s) are in use.

2. x - Numeric variable with x values. Elements in x or its standard-specific equivalents (age_days, length_cm, and height_cm) should have specific units and be between certain values depending on the standard in use (defined by acronym). These are:

   • Between 0 and 1856 days for "wfa", "bfa", "lhfa", and "hcfa".
   • Between 45 and 110 cm for "wfl".
   • Between 65 and 120 cm for "wfh".
   • Between 91 and 1856 days for "acfa", "ssfa", "tsfa".

   By default, gigs will return missing value (.) for out-of-bounds elements in x.

3. sex - Character variable with sex(es), either "M" (male) or "F" (female).

4. acronym - Character variable denoting the WHO Child Growth standard(s) in use. Each element should be one of:

   • "wfa" (weight-for-age)
   • "bfa" (BMI-for-age)
   • "lhfa" (length/height-for-age)
   • "wfl" (weight-for-length)
   • "wfh" (weight-for-height)
   • "hcfa" (head circumference-for-age)
   • "acfa" (arm circumference-for-age)
   • "ssfa" (subscapular skinfold-for-age)
   • "tsfa" (triceps skinfold-for-age)

Returns

Numeric variable of centiles for each measurement.

Note

For each acronym from the list: "wfa", "bfa", "lhfa", "wfl", "wfh", "hcfa", "acfa", "ssfa", and "tsfa" a counterpart "acronym function", which is a wrapper for the gigs_who_gs_value2centile, is generated. The "acronym function" has the following form:

gigs_who_gs_<acronym>_value2centile(y, x, sex)

Complete list is:

gigs_who_gs_wfa_value2centile(weight_kg, age_days, sex)

gigs_who_gs_bfa_value2centile(bmi, age_days, sex)

gigs_who_gs_lhfa_value2centile(lenht_cm, age_days, sex)

gigs_who_gs_wfl_value2centile(weight_kg, length_cm, sex)

gigs_who_gs_wfh_value2centile(weight_kg, height_cm, sex)

gigs_who_gs_hcfa_value2centile(headcirc_cm, age_days, sex)

gigs_who_gs_acfa_value2centile(armcirc_cm, age_days, sex)

gigs_who_gs_ssfa_value2centile(subscap_sf_mm, age_days, sex)

gigs_who_gs_tsfa_value2centile(triceps_sf_mm, age_days, sex)

Parameters meaning:

• weight_kg - Numeric variable with weight measurement(s) in kg.
• bmi - Numeric variable with body mass index measurement(s) in kg/m².
• lenht_cm - Numeric variable with length/height measurement(s) in cm.
• headcirc_cm - Numeric variable with head circumference measurement(s) in cm.
• armcirc_cm - Numeric variable with arm circumference measurement(s) in cm.
• subscap_sf_mm - Numeric variable with subscapular skinfold measurement(s) in mm.
• triceps_sf_mm - Numeric variable with triceps skinfold measurement(s) in mm.

Those functions are generated by the %gigs_who_gs_acronym() macro.

See also

The function internally use gigs_who_gs_value2zscore and SAS CDF functions.

References

de Onis M, Garza C, Victora CG, Onyango AW, Frongillo EA, Martines J. The WHO Multicentre Growth Reference Study: planning, study design, and methodology Food Nutr Bull. 2004, 25(1 Suppl):S15-26. doi: 10.1177/15648265040251s104

World Health Organisation. WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: methods and development. Technical report, WHO, Geneva, 2006.

World Health Organisation. WHO child growth standards: head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age: methods and development. Technical report, WHO, Geneva, 2007.

Cole TJ. The LMS method for constructing normalized growth standards Eur J Clin Nutr. 1990, 44(1):45-60. PMID: 2354692

Examples

1. Convert values to centiles

data have;
  input weight_kg age_days sex :$1.;
CARDS4;
10.1 504 M
10.2 505 F
10.3 506 M
;;;;
run;

data get;
  set have;
  acronym = "wfa";
  
  centile = gigs_who_gs_value2centile(
    weight_kg
  , age_days 
  , sex
  , acronym
  );
run;

---

---

gigs_ig_nbs_value2zscore() function

Convert values to z-scores in the INTERGROWTH-21^st Newborn Size Standards

Syntax

  function gigs_ig_nbs_value2zscore(
    y
  , gest_days
  , sex $
  , acronym $
  );

---

Arguments

1. y - Numeric variable with measurements to convert to z-score.

2. gest_days - Numeric variable with gestational ages in days. Elements should be between certain values depending on the Newborn Size standard in use (defined by acronym). These are:

   • Between 168 and 300 days for "wfga", "lfga", "hcfga", and "wlrfga".
   • Between 154 and 280 days for "fmfga", "bfpfga", and "ffmfga". By default, gigs will ignore gest_days that are out of bounds for the growth standard and return missing value (.).

3. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

4. acronym - Character variable denoting the INTERGROWTH-21^st Newborn Size standard to use for each observation. Each element should be one of:

   • "wfga" (weight-for-GA)
   • "lfga" (length-for-GA)
   • "hcfga" (head circumference-for-GA)
   • "wlrfga" (weight/length ratio-for-GA)
   • "fmfga" (fat mass-for-GA)
   • "bfpfga" (body fat %-for-GA)
   • "ffmfga" (fat-free mass-for-GA) This argument is not case-sensitive.

Returns

Numeric variable of expected z-scores for each measurement.

Note

For each acronym from the list: "wfga", "lfga", "hcfga", "wlrfga", "fmfga", "bfpfga", and "ffmfga"
a counterpart "acronym function", which is a wrapper for the gigs_ig_nbs_value2zscore, is generated. The "acronym function" has the following form:

gigs_ig_nbs_<acronym>_value2zscore(y, gest_days, sex)

Complete list is:

gigs_ig_nbs_wfga_value2zscore(weight_kg, gest_days, sex)

gigs_ig_nbs_lfga_value2zscore(length_cm, gest_days, sex)

gigs_ig_nbs_hcfga_value2zscore(headcirc_cm, gest_days, sex)

gigs_ig_nbs_wlrfga_value2zscore(wei_len_ratio, gest_days, sex)

gigs_ig_nbs_fmfga_value2zscore(fat_mass_g, gest_days, sex)

gigs_ig_nbs_bfpfga_value2zscore(body_fat_perc, gest_days, sex)

gigs_ig_nbs_ffmfga_value2zscore(fatfree_mass_g, gest_days, sex

Parameters meaning:

• weight_kg - Numeric variable with birth weight(s) in kg.
• length_cm - Numeric variable with birth length(s) in cm.
• headcirc_cm - Numeric variable with birth head circumference(s) in cm.
• wei_len_ratio - Numeric variable with weight-length ratio(s) in kg per m.
• fat_mass_g - Numeric variable with fat mass(es) in g.
• body_fat_perc - Numeric variable with body fat percentage(s).
• fatfree_mass_g - Numeric variable with fat-free mass(es) in g.

Those functions are generated by the %gigs_ig_nbs_acronym() macro.

See also

The function internally utilizes the following functions: gigs_ig_nbs_value2centile, and SAS QUANTILE.

References

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH et al. INTERGROWTH-21st very preterm size at birth reference charts. Lancet 2016, 387(10021):844-45. doi: 10.1016/S0140-6736(16)00384-6

Villar J, Puglia FA, Fenton TR, Ismal LC, Staines-Urias E, Giuliani F, et al. Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project. Pediatric Research 2017, 82:305-316. doi: 10.1038/pr.2017.52

Examples

1. Convert values to z-scores

data have;
  input y gest_days sex :$1. acronym :$6.;
CARDS4;
2.90  274 F wfga
3.17  275 F wfga
3.46  276 F wfga
48.84 280 M lfga
;;;;
run;

data get;
  set have;
  
  zScore=gigs_ig_nbs_value2zscore(
    y
  , gest_days
  , sex
  , acronym
  );
run;

2. Use of "acronym function"

data get_lfga;
  length_cm = 48.84;
  gest_days = 280;
  sex = "M";

  zscore = gigs_ig_nbs_lfga_value2zscore(
    length_cm
  , gest_days
  , sex
);
run;

---

---

gigs_ig_nbs_zscore2value() function

Convert z-scores to values in the INTERGROWTH-21^st Newborn Size Standards

Syntax

function gigs_ig_nbs_zscore2value(
  z
, gest_days
, sex $
, acronym $
);

---

Arguments

1. z - Numeric variable with z-scores to convert to values.

2. gest_days - Numeric variable with gestational ages in days. Elements should be between certain values depending on the Newborn Size standard in use (defined by acronym). These are:

   • Between 168 and 300 days for "wfga", "lfga", "hcfga", and "wlrfga".
   • Between 154 and 280 days for "fmfga", "bfpfga", and "ffmfga". By default, gigs will ignore gest_days that are out of bounds for the growth standard and return missing value (.).

3. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

4. acronym - Character variable denoting the INTERGROWTH-21^st Newborn Size standard to use for each observation. Each element should be one of:

   • "wfga" (weight-for-GA)
   • "lfga" (length-for-GA)
   • "hcfga" (head circumference-for-GA)
   • "wlrfga" (weight/length ratio-for-GA)
   • "fmfga" (fat mass-for-GA)
   • "bfpfga" (body fat %-for-GA)
   • "ffmfga" (fat-free mass-for-GA)

   This argument is not case-sensitive.

Returns

Numeric variable of expected measurements for each z-score.

Note

For each acronym from the list: "wfga", "lfga", "hcfga", "wlrfga", "fmfga", "bfpfga", and "ffmfga"
a counterpart "acronym function", which is a wrapper for the gigs_ig_nbs_zscore2value, is generated. The "acronym function" has the following form:

gigs_ig_nbs_<acronym>_zscore2value(z, gest_days, sex)

Complete list is:

gigs_ig_nbs_wfga_zscore2value(z, gest_days, sex)

gigs_ig_nbs_lfga_zscore2value(z, gest_days, sex)

gigs_ig_nbs_hcfga_zscore2value(z, gest_days, sex)

gigs_ig_nbs_wlrfga_zscore2value(z, gest_days, sex)

gigs_ig_nbs_fmfga_zscore2value(z, gest_days, sex)

gigs_ig_nbs_bfpfga_zscore2value(z, gest_days, sex)

gigs_ig_nbs_ffmfga_zscore2value(z, gest_days, sex)

Those functions are generated by the %gigs_ig_nbs_acronym() macro.

See also

The function internally utilizes the gigs_ig_nbs_centile2value function and transforms z value to a centile value with CDF('GAUSS', z, 0, 1) function.

References

Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet 2014, 384(9946):857-68. doi: 10.1016/S0140-6736(14)60932-6

Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH et al. INTERGROWTH-21st very preterm size at birth reference charts. Lancet 2016, 387(10021):844-45. doi: 10.1016/S0140-6736(16)00384-6

Villar J, Puglia FA, Fenton TR, Ismal LC, Staines-Urias E, Giuliani F, et al. Body composition at birth and its relationship with neonatal anthropometric ratios: the newborn body composition study of the INTERGROWTH-21st project. Pediatric Research 2017, 82:305-316. doi: 10.1038/pr.2017.52

---

---

%gigs_ig_fet_acronym() macro

The macro produces:

• gigs_ig_fet_<acronym>_value2centile,

• gigs_ig_fet_<acronym>_value2zscore,

• gigs_ig_fet_<acronym>_zscore2value, and

• gigs_ig_fet_<acronym>_centile2value

functions group for the following list of acronyms:

hcfga bpdfga acfga flfga ofdfga hefwfga efwfga sfhfga crlfga gafcrl gwgfga pifga rifga sdrfga tcdfga gaftcd poffga sffga avfga pvfga cmfga

Requires the macroArray package to work.

See also

Details about how to use those functions can be found in the documentation of the following functions:

• gigs_ig_fet_value2centile,
• gigs_ig_fet_value2zscore,
• gigs_ig_fet_zscore2value, and
• gigs_ig_fet_centile2value.

Synatax

%macro gigs_ig_fet_acronym();

---

---

%gigs_ig_nbs_acronym() macro

The macro produces:

• gigs_ig_nbs_<acronym>_value2centile,

• gigs_ig_nbs_<acronym>_value2zscore,

• gigs_ig_nbs_<acronym>_zscore2value, and

• gigs_ig_nbs_<acronym>_centile2value

functions group for the following list of acronyms:

wfga lfga hcfga wlrfga fmfga bfpfga ffmfga

Requires the macroArray package to work.

See also

Details about how to use those functions can be found in the documentation of the following functions:

• gigs_ig_nbs_value2centile,
• gigs_ig_nbs_value2zscore,
• gigs_ig_nbs_zscore2value, and
• gigs_ig_nbs_centile2value.

Synatax

%macro gigs_ig_nbs_acronym();

---

---

%gigs_ig_png_acronym() macro

The macro produces:

• gigs_ig_png_<acronym>_value2centile,

• gigs_ig_png_<acronym>_value2zscore,

• gigs_ig_png_<acronym>_zscore2value, and

• gigs_ig_png_<acronym>_centile2value

functions group for the following list of acronyms:

wfa lfa hcfa wfl

Requires the macroArray package to work.

See also

Details about how to use those functions can be found in the documentation of the following functions:

• gigs_ig_png_value2centile,
• gigs_ig_png_value2zscore,
• gigs_ig_png_zscore2value, and
• gigs_ig_png_centile2value.

Synatax

%macro gigs_ig_png_acronym();

---

---

%gigs_who_gs_acronym() macro

The macro produces:

• gigs_who_gs_<acronym>_value2centile,

• gigs_who_gs_<acronym>_value2zscore,

• gigs_who_gs_<acronym>_zscore2value, and

• gigs_who_gs_<acronym>_centile2value

functions group for the following list of acronyms:

wfa bfa lhfa wfl wfh hcfa acfa ssfa tsfa

Requires the macroArray package to work.

See also

Details about how to use those functions can be found in the documentation of the following functions:

• gigs_who_gs_<acronym>_value2centile,
• gigs_who_gs_<acronym>_value2zscore,
• gigs_who_gs_<acronym>_zscore2value, and
• gigs_who_gs_<acronym>_centile2value.

Synatax

%macro gigs_who_gs_acronym();

---

---

gigs_acronym_functions exec

Description

The exec code purpose is to generate all the "acronym functions" in the package.

The following macros are executed:

%gigs_ig_fet_acronym();
%gigs_ig_nbs_acronym();
%gigs_ig_png_acronym();
%gigs_who_gs_acronym();

See their documentation for the details.

If this exec code is disabled from execution gigs will not function correctly.

Note

Temporary global macro variables: __acronym1 to __acronymN, __variableX1 to __variableXN, __variableY1 to __variableYN and %__acronym(), %__variableX(), %__variableY() macros are generated. All are deleted when the code finishes.

---

---

gigs_acronym_functions clean

Description

Code cleans up after "acronym" macros.

The macroArray package is required to run this cleaning code.

Note

Temporary global macro variables: __acronym1 to __acronymN and %__acronym() macro are generated. All are deleted when the code finishes.

---

---

gigs_categorise_sfga() function

Categorise birthweight centiles into size-for-gestational age strata

Syntax

  function gigs_categorise_sfga(
    p
  , severe /*=0 FALSE*/
  ) $ 8 ;

---

Arguments

1. p - Numeric variable with birth weight centiles from the INTERGROWTH-21^st Newborn Size standard.

2. severe - A logical value specifying whether to categorise SGA values are below the third centile as "SGA(<3)".

Returns

A character variable of length 8 containing size-for-GA classifications. If severe is 0, possible values are: "SGA", "AGA", and "LGA". If severe is 1, list of levels is extended by "SGA(<3)" value.

Usage Note

[Important.] The function assumes that values provided are taken from a newborn, i.e., at birth. The function does not check age since birth! If your measurements were taken postnatally the returned values may be undesirable.

References

WHO. Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. World Health Organisation Technical Report Series 1995, 854: 1–452

Royal College of Obstetricians and Gynaecologists. The Investigation and Management of the Small-for-Gestational-Age Fetus: Green-top Guideline No. 31. Technical report, Royal College of Obstetricians and Gynaecologists, London, 2013.

---

Examples

1. By default, does not differentiate between p < 0.03 and p < 0.10

data have;
  input p;
cards4;
0.02
0.11
0.25
0.5
0.75
0.99
;;;;
run;

data get;
  set have;
  
  sfga = gigs_categorise_sfga(
    p,
    0
  );
run;

2. With severe = 1, highlights p < 0.03

data get;
  set have;
  
  severe = 1;
  
  sfgaSevere = gigs_categorise_sfga(
    p,
    severe
  );
run;

---

gigs_compute_sfga() function

Compute size-for-gestational age categories using the INTERGROWTH-21st weight-for-gestational age standard

Syntax

  function gigs_compute_sfga(
    weight_kg
  , gest_days
  , sex $
  , severe /*=0 FALSE*/
  ) $ 8 ;

---

Arguments

1. weight_kg - Numeric variable with weight value(s) in kg.

2. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

3. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

4. severe - A logical value specifying whether to categorise SGA values are below the third centile as "SGA(<3)".

Returns

A character variable of length 8 containing size-for-GA classifications. If severe is 0, possible values are: "SGA", "AGA", and "LGA". If severe is 1, list of levels is extended by "SGA(<3)" value.

Usage Note

[Important.] The function assumes that values provided are taken from a newborn, i.e., at birth. The function does not check age since birth! If your measurements were taken postnatally the returned values may be undesirable.

See also

See the [gigs_ig_nbs_value2centile()] function, which this function calls to get centiles for each observation.

References

WHO. Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. World Health Organisation Technical Report Series 1995, 854: 1–452

Royal College of Obstetricians and Gynaecologists. The Investigation and Management of the Small-for-Gestational-Age Fetus: Green-top Guideline No. 31. Technical report, Royal College of Obstetricians and Gynaecologists, London, 2013.

---

Examples

1. By default, does not differentiate between p < 0.03 and p < 0.10

data have;
  input weight_kg gest_days sex :$1.;
cards4;
2.2 267 M
3.3 268 F
4.4 269 M
;;;;
run;

data get;
  set have;
  
  sfga = gigs_compute_sfga(
    weight_kg,
    gest_days,
    sex,
    0
  );
run;

2. With severe = 1, highlights p < 0.03

data get;
  set have;
  
  severe = 1;
  
  sfgaSevere = gigs_compute_sfga(
    weight_kg,
    gest_days,
    sex,
    severe
  );
run;

---

gigs_categorise_headsize() function

Categorise head circumference-for-age z-scores into head circumference-for-age strata

Syntax

function gigs_categorise_headsize(
  hcaz
) $ 20;

---

Arguments

1. hcaz - Numeric variable containing head circumference-for-age z-scores (HCAZs).

Returns

A character variable of length 20 head circumference-for-age classifications. Its levels are "microcephaly_severe", "microcephaly", "normal_headcirc", "macrocephaly", and "macrocephaly_severe".

References

Victora CG, Schuler-Faccini L, Matijasevich A, Ribeiro E, Pessoa A, Barros FC. Microcephaly in Brazil: how to interpret reported numbers? The Lancet 2016, 387(10019):621-624 doi: 10.1016/S0140-6736(16)00273-7

Accogli A, Geraldo AF, Piccolo G, Riva A, Scala M, Balagura G, et al. Diagnostic Approach to Macrocephaly in Children. Frontiers in Paediatrics 2022, 9:794069 doi: 10.3389/fped.2021.794069

---

Examples

1. The first observation uses the INTERGROWTH-21st Postnatal Growth standards; the next two use the WHO Child Growth Standards.

data have;
  input hcaz;
cards4;
-6.5
-3.5
-2.5
0
2.5
3.5
;;;;
run;

data get;
  set have;
  
  headsize = gigs_categorise_headsize(
    hcaz
  );
run;

---

---

gigs_categorise_stunting() function

Categorise length/height-for-age z-scores into stunting strata

Syntax

function gigs_categorise_stunting(
  lhaz
, outliers /*=0 FALSE*/
) $ 16;

---

Arguments

1. lhza - Numeric variable containing length/height-for-age z-scores (LHAZs).

2. outliers - A single TRUE or FALSE value specifying whether implausible z-score value thresholds should be applied.

Returns

A character variable of length 16 containing stunting classifications. Its levels are "stunting_severe", "stunting", and "not_stunting". If outliers is 1 the list is extended by additional "outlier" value.

Note

This function assumes that your measurements were taken according to the WHO guidelines, which stipulate that recumbent length should not be measured after 730 days. Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Examples

1. The first observation uses the INTERGROWTH-21st Postnatal Growth standards; the next two use the WHO Child Growth Standards.

data have;
  input lhaz;
cards4;
-6.5
-5
-3
0
3
5
6.5
;;;;
run;

data get;
  set have;
  
  stunting = gigs_categorise_stunting(
    lhaz,
    0
  );
run;

2. And with outlier flagging:

data get;
  set have;
  
  outliers = 1;
  
  stuntingOut = gigs_categorise_stunting(
    lhaz,
    outliers
  );
run;

---

---

gigs_categorise_svn() function

Categorise birthweight centiles and gestational ages into small vulnerable newborn strata

Syntax

function gigs_categorise_svn(
  p
, gest_days) 
$ 16; 

---

Arguments

1. p - Numeric variable with birth weight centiles from the INTERGROWTH-21^st Newborn Size standard.

2. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

Returns

A character variable of length 16 containing small vulnerable newborn classifications. Its levels are: "Preterm SGA", "Preterm AGA", "Preterm LGA", "Term SGA", "Term AGA", and "Term LGA".

Usage Note

[Important.] The function assumes that values provided are taken from a newborn, i.e., at birth. The function does not check age since birth! If your measurements were taken postnatally the returned values may be undesirable.

See also

See the gigs_category_sfga() function, which this function calls to get classifications for each observation.

References

Lawn JE, Ohuma EO, Bradley E, Idueta LS, Hazel E, Okwaraji YB et al. Small babies, big risks: global estimates of prevalence and mortality for vulnerable newborns to accelerate change and improve counting. The Lancet 2023, 401(10389):1707-1719. doi: 10.1016/S0140-6736(23)00522-6

---

Examples

1. Basic classification:

data have;
  input p gest_days;
cards4;
0.02 235
0.11 257
0.25 235
0.5  275
0.75 235
0.99 295
;;;;
run;

data get;
  set have;
  
  svn = gigs_categorise_svn(
    p,
    gest_days
  );
run;

---

---

gigs_categorise_wasting() function

Categorise weight-for-length/height z-scores into wasting strata

Categorise wasting (low weight-for-length/height) using the INTERGROWTH-21^st weight-for-length or WHO Child Growth standards, specifically either the weight-for-length or weight-for-height standard depending on the age of the child. Severe wasting is <-3SD relative to the mean expected weight, whereas moderate wasting is -2SD from the mean.

Syntax

function gigs_categorise_wasting(
  wlz
, outliers /*=0 FALSE*/
) $ 20;

---

Arguments

1. wlz - Numeric variable with weight value(s) in kg.

2. outliers - A single TRUE or FALSE value specifying whether implausible z-score value thresholds should be applied.

Returns

A character variable of length 20 containing wasting classifications. Its levels are "wasting_severe", "wasting", "not_wasting", and "overweight". If outliers is 1 the list is extended by additional "outlier" value.

Note

Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Examples

1. Returns factor with stunting classifications

data have;
  input wlz;
CARDS4;
-5.5 
-3 
0 
3 
5.5
;;;;
run;

data get;
  set have;
  
  wasting = gigs_categorise_wasting(
    wlz,
    0
  );
run;

2. Outliers can be flagged if outliers set to 1

data get;
  set have;
  
  outliers = 1;
  
  wastingOut = gigs_categorise_wasting(
    wlz,
    outliers
  );
run;

---

---

gigs_categorise_wfa() function

Categorise weight-for-age z-scores into weight-for-age strata

Syntax

function gigs_categorise_wfa(
  waz
, outliers /*=0 FALSE*/
) $ 20;

---

Arguments

1. waz - Numeric variable containing weight-for-age z-scores (WAZs).

2. outliers - A single TRUE or FALSE value specifying whether implausible z-score value thresholds should be applied.

Returns

A character variable of length 20 containing weight-for-age classifications. Its levels are "underweight_severe", "underweight", "normal", and "overweight". If outliers is 1 the list is extended by additional "outlier" value.

Note

Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Examples

1. Weight-for-age classifications

data have;
  input waz;
CARDS4;
-6.5
-3.5
-2.5
0
2.5
  3.5
;;;;
run;

data get;
  set have;
  
  wfa = gigs_categorise_wfa(
    waz,
    0
  );
  
  wfaOut = gigs_categorise_wfa(
    waz,
    1
  );
run;

---

---

gigs_compute_headsize() function

Get head size categories using anthropometric measurements and GIGS-recommended growth standards

Syntax

function gigs_compute_headsize(
  headcirc_cm
, age_days
, gest_days
, sex $
, isBirthMeasurement
) $ 20;

---

Arguments

1. headcirc_cm - Numeric variable with head circumference measurement(s) in cm.

2. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

3. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

4. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

5. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

A character variable of length 20 head circumference-for-age classifications. Its levels are "microcephaly_severe", "microcephaly", "normal_headcirc", "macrocephaly", and "macrocephaly_severe".

References

Victora CG, Schuler-Faccini L, Matijasevich A, Ribeiro E, Pessoa A, Barros FC. Microcephaly in Brazil: how to interpret reported numbers? The Lancet 2016, 387(10019):621-624 doi: 10.1016/S0140-6736(16)00273-7

Accogli A, Geraldo AF, Piccolo G, Riva A, Scala M, Balagura G, et al. Diagnostic Approach to Macrocephaly in Children. Frontiers in Paediatrics 2022, 9:794069 doi: 10.3389/fped.2021.794069

---

Examples

1. Categorise head circumference-for-age.

data have;
  input headcirc_cm age_days gest_days sex :$1.;
cards4;
41 357 196 M
40 375 287 M
41 250 266 F
51 250 266 F
;;;;
run;

data get;
  set have;
  
  stunting = gigs_compute_headsize(
    headcirc_cm,
    age_days,
    gest_days,
    sex,
    0
  );
run;

---

---

gigs_compute_stunting() function

Get stunting categories using anthropometric measurements and GIGS-recommended growth standards

Syntax

function gigs_compute_stunting(
  lenht_cm
, age_days
, gest_days
, sex $
, outliers /*=0 FALSE*/
, isBirthMeasurement
) $ 16;

---

Arguments

1. lenht_cm - Numeric variable with length/height measurement(s) in cm.

2. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

3. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

4. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

5. outliers - A single TRUE or FALSE value specifying whether implausible z-score value thresholds should be applied.

6. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

A character variable of length 16 containing stunting classifications. Its levels are "stunting_severe", "stunting", and "not_stunting". If outliers is 1 the list is extended by additional "outlier" value.

Note

This function assumes that your measurements were taken according to the WHO guidelines, which stipulate that recumbent length should not be measured after 730 days. Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Examples

1. The first observation uses the INTERGROWTH-21st Postnatal Growth standards; the next two use the WHO Child Growth Standards.

data have;
  input lenht_cm age_days gest_days sex :$1.;
cards4;
52.2 357 196 M
75.4 375 287 M
63.1 250 266 F
;;;;
run;

data get;
  set have;
  
  stunting = gigs_compute_stunting(
    lenht_cm,
    age_days,
    gest_days,
    sex,
    0,
    0
  );
run;

2. And with outlier flagging:

data get;
  set have;
  
  outliers = 1;
  
  stuntingOut = gigs_compute_stunting(
    lenht_cm,
    age_days,
    gest_days,
    sex,
    outliers,
    0
  );
run;

---

---

gigs_compute_svn() function

Get small vulnerable newborn categories using anthropometric measurements and GIGS-recommended growth standards

Syntax

function gigs_compute_svn(
  weight_kg
, gest_days
, sex $) $ 16; 

---

Arguments

1. weight_kg - Numeric variable with weight value(s) in kg.

2. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

3. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

Returns

A character variable of length 16 containing small vulnerable newborn classifications. Its levels are: "Preterm SGA", "Preterm AGA", "Preterm LGA", "Term SGA", "Term AGA", and "Term LGA".

Usage Note

[Important.] The function assumes that values provided are taken from a newborn, i.e., at birth. The function does not check age since birth! If your measurements were taken postnatally the returned values may be undesirable.

See also

See the gigs_compute_sfga() function, which this function calls to get classifications for each observation.

References

Lawn JE, Ohuma EO, Bradley E, Idueta LS, Hazel E, Okwaraji YB et al. Small babies, big risks: global estimates of prevalence and mortality for vulnerable newborns to accelerate change and improve counting. The Lancet 2023, 401(10389):1707-1719. doi: 10.1016/S0140-6736(23)00522-6

---

Examples

1. Basic classification:

data have;
  input weight_kg gest_days sex :$1.;
cards4;
1.5 235 F
2.6 257 M
2.6 275 F
3.5 295 M
;;;;
run;

data get;
  set have;
  
  svn = gigs_compute_svn(
    weight_kg,
    gest_days,
    sex
  );
run;

---

---

gigs_compute_wasting() function

Get wasting categories using anthropometric measurements and GIGS-recommended growth standards

Syntax

function gigs_compute_wasting(
  weight_kg
, lenht_cm
, age_days
, gest_days
, sex $
, outliers /*=0 FALSE*/
, isBirthMeasurement
) $ 20;

---

Arguments

1. weight_kg - Numeric variable with weight value(s) in kg.

2. lenht_cm - Numeric variable with length/height measurement(s) in cm.

3. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

4. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

5. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

6. outliers - A single TRUE or FALSE value specifying whether implausible z-score value thresholds should be applied.

7. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

A character variable of length 20 containing wasting classifications. Its levels are "wasting_severe", "wasting", "not_wasting", and "overweight". If outliers is 1 the list is extended by additional "outlier" value.

Note

Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Examples

1. Returns factor with wasting classifications

data have;
  input weight_kg lenht_cm gest_days age_days sex :$1.;
CARDS4;
5.75 67.7 251 251 F
2.18 46.6 197 197 M
3.00 50.0 225 225 F
6.75 80.1 243 243 M
;;;;
run;

data get;
  set have;
  
  wasting = gigs_compute_wasting(
    weight_kg,
    lenht_cm,
    age_days,
    gest_days,
    sex,
    0,
    0
  );
run;

2. Outliers can be flagged if outliers set to 1

data get;
  set have;
  
  outliers = 1;
  
  wastingOut = gigs_compute_wasting(
    weight_kg,
    lenht_cm,
    age_days,
    gest_days,
    sex,
    outliers,
    0
  );
run;

---

---

gigs_compute_wfa() function

Get weight-for-age categories using anthropometric measurements and GIGS-recommended growth standards

Syntax

function gigs_compute_wfa(
  weight_kg
, age_days
, gest_days
, sex $
, outliers /*=0 FALSE*/
, isBirthMeasurement
) $ 20;

---

Arguments

1. weight_kg - Numeric variable with weight value(s) in kg.

2. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

3. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

4. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

5. outliers - A single TRUE or FALSE value specifying whether implausible z-score value thresholds should be applied.

6. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

A character variable of length 20 containing weight-for-age classifications. Its levels are "underweight_severe", "underweight", "normal", and "overweight". If outliers is 1 the list is extended by additional "outlier" value.

Note

Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Examples

1. Weight-for-age classifications

data have;
  input weight_kg gest_days age_days sex :$1.;
CARDS4;
7.2  401 189 F
4.5  185 252 M
9.1  101 280 F
24.0 607 287 M
;;;;
run;

data get;
  set have;
  
  wfa = gigs_compute_wfa(
    weight_kg,
    age_days,
    gest_days,
    sex,
    0,
    0
  );
  
  wfaOut = gigs_compute_wfa(
    weight_kg,
    age_days,
    gest_days,
    sex,
    1,
    0
  );
run;

---

---

gigs_classify_headsize() function

Classify head size using GIGS-recommended standards

Syntax

subroutine gigs_classify_headsize(
  zScore
, headsize $
, headcirc_cm
, age_days
, gest_days
, sex $
, isBirthMeasurement
);
  OUTARGS zScore, headsize;

---

Arguments

1. zScore - Numeric variable, of type OUTARGS, with z-score.

2. headsize - Character variable of length 20, of type OUTARGS, with classification category.

3. headcirc_cm - Numeric variable with head circumference measurement(s) in cm.

4. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

5. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

6. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

7. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

Variable category contains head circumference classifications. Levels are "microcephaly_severe", "microcephaly", "normal_headcirc", "macrocephaly", and "macrocephaly_severe".

References

Victora CG, Schuler-Faccini L, Matijasevich A, Ribeiro E, Pessoa A, Barros FC. Microcephaly in Brazil: how to interpret reported numbers? The Lancet 2016, 387(10019):621-624 doi: 10.1016/S0140-6736(16)00273-7

Accogli A, Geraldo AF, Piccolo G, Riva A, Scala M, Balagura G, et al. Diagnostic Approach to Macrocephaly in Children. Frontiers in Paediatrics 2022, 9:794069 doi: 10.3389/fped.2021.794069

---

Examples

1. The first observation uses the INTERGROWTH-21st Postnatal Growth standards; the next two use the WHO Child Growth Standards.

data have;
  input headcirc_cm age_days gest_days sex :$1.;
cards4;
41 357 196 M
40 375 287 M
41 250 266 F
51 250 266 F
;;;;
run;


data get;
  set have;
  
  length zscore 8 headsize $ 20;
  call missing(zscore, headsize);
  
  call gigs_classify_headsize(
    zscore, 
    headsize,
    headcirc_cm,
    age_days,
    gest_days,
    sex,
    0
  );
run;

---

---

gigs_classify_sfga() function

Classify size-for-gestational age using the INTERGROWTH-21^st Newborn Size standard for weight-for-gestational age

Syntax

subroutine gigs_classify_sfga(
  centile
, sfga $
, sfgaSev $
, weight_kg
, gest_days
, sex $
);
  OUTARGS centile, sfga, sfgaSev;

---

Arguments

1. centile - Numeric variable, of type OUTARGS, with centile.

2. sfga - Character variable of length 8, of type OUTARGS, with classification category.

3. sfgaSev - Character variable of length 8, of type OUTARGS, with classification category taking severity into account.

4. weight_kg - Numeric variable with weight value(s) in kg.

5. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

6. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

Returns

Variables sfga and sfgaSev contain size-for-GA classifications. Possible values are: "SGA", "AGA", and "LGA". For sfgaSev list of levels is extended by "SGA(<3)" value.

Usage Note

[Important.] The function assumes that values provided are taken from a newborn, i.e., at birth. The function does not check age since birth! If your measurements were taken postnatally the returned values may be undesirable.

See also

See the gigs_ig_nbs_value2centile() function, which this function calls to get centiles for each observation.

References

WHO. Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. World Health Organisation Technical Report Series 1995, 854: 1–452

Royal College of Obstetricians and Gynaecologists. The Investigation and Management of the Small-for-Gestational-Age Fetus: Green-top Guideline No. 31. Technical report, Royal College of Obstetricians and Gynaecologists, London, 2013.

---

Examples

1. By default, does not differentiate between p < 0.03 and p < 0.10

data have;
  input weight_kg gest_days sex :$1.;
cards4;
2.2 267 M
3.3 268 F
4.4 269 M
;;;;
run;

data get;
  set have;

  length centile 8 sfga sfgaSev $ 20;
  call missing(centile, sfga, sfgaSev);
  
  call gigs_classify_sfga(
    centile, 
    sfga, 
    sfgaSev,
    weight_kg,
    gest_days,
    sex
  );
run;

---

---

gigs_classify_stunting() function

Classify stunting using GIGS-recommended standards

Syntax

subroutine gigs_classify_stunting(
  zScore
, stunting $
, stuntingOut $
, lenht_cm
, age_days
, gest_days
, sex $
, isBirthMeasurement
);
  OUTARGS zScore, stunting, stuntingOut;

---

Arguments

1. zScore - Numeric variable, of type OUTARGS, with z-score.

2. stunting - Character variable of length 20, of type OUTARGS, with classification category.

3. stuntingOut - Character variable of length 20, of type OUTARGS, with classification category taking outliers into account.

4. lenht_cm - Numeric variable with length/height measurement(s) in cm.

5. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

6. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

7. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

8. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

Variables stunting and stuntingOut contain stunting classifications. Levels are "stunting_severe", "stunting", and "not_stunting". For stuntingOut the list is extended by additional "outlier" value.

Note

This function assumes that your measurements were taken according to the WHO guidelines, which stipulate that recumbent length should not be measured after 730 days. Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

---

Examples

1. The first observation uses the INTERGROWTH-21st Postnatal Growth standards; the next two use the WHO Child Growth Standards.

data have;
  input lenht_cm age_days gest_days sex :$1.;
cards4;
52.2 357 196 M
75.4 375 287 M
63.1 250 266 F
;;;;
run;

data get;
  set have;
  
  length zscore 8 stunting stuntingOut $ 20;
  call missing(zscore, stunting, stuntingOut);
  
  call gigs_classify_stunting(
    zscore, 
    stunting, 
    stuntingOut,
    lenht_cm,
    age_days,
    gest_days,
    sex,
    0
  );
run;

---

---

gigs_classify_svn() function

Classify small vulnerable newborns using the INTERGROWTH-21^st Newborn Size standard for weight-for-gestational age

Syntax

subroutine gigs_classify_svn(
  centile
, svn $
, weight_kg
, gest_days
, sex $
);
  OUTARGS centile, svn;

---

Arguments

1. centile - Numeric variable, of type OUTARGS, with centile.

2. svn - Character variable of length 16, of type OUTARGS, with classification category.

3. weight_kg - Numeric variable with weight value(s) in kg.

4. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

5. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

Returns

Variable svn contains size-for-GA classifications. Possible values are: "SGA", "AGA", and "LGA". With a "Term" or "Preterm" prefix.

Usage Note

[Important.] The function assumes that values provided are taken from a newborn, i.e., at birth. The function does not check age since birth! If your measurements were taken postnatally the returned values may be undesirable.

See also

See the gigs_ig_nbs_value2centile() function, which this function calls to get centiles for each observation.

References

WHO. Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. World Health Organisation Technical Report Series 1995, 854: 1–452

Royal College of Obstetricians and Gynaecologists. The Investigation and Management of the Small-for-Gestational-Age Fetus: Green-top Guideline No. 31. Technical report, Royal College of Obstetricians and Gynaecologists, London, 2013.

---

Examples

1. Simple calculation.

data have;
  input weight_kg gest_days sex :$1.;
cards4;
2.2 267 M
3.3 268 F
4.4 269 M
;;;;
run;

data get;
  set have;

  length centile 8 svn $ 20;
  call missing(centile, svn);
  
  call gigs_classify_svn(
    centile, 
    svn, 
    weight_kg,
    gest_days,
    sex
  );
run;

---

---

gigs_classify_wasting() function

Classify wasting using GIGS-recommended standards

Syntax

subroutine gigs_classify_wasting(
  zScore
, wasting $
, wastingOut $
, weight_kg
, lenht_cm
, age_days
, gest_days
, sex $
, isBirthMeasurement
);
  OUTARGS zScore, wasting, wastingOut;

---

Arguments

1. zScore - Numeric variable, of type OUTARGS, with z-score.

2. wasting - Character variable of length 20, of type OUTARGS, with classification category.

3. wastingOut - Character variable of length 20, of type OUTARGS, with classification category taking outliers into account.

4. weight_kg - Numeric variable with weight value(s) in kg.

5. lenht_cm - Numeric variable with length/height measurement(s) in cm.

6. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

7. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

8. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

9. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

Variables wasting and wastingOut contain wasting classifications. Levels are "wasting_severe", "wasting", "not_wasting", and "overweight". For wastingOut the list is extended by additional "outlier" value.

Note

Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

---

Examples

1. Returns factor with stunting classifications

data have;
  input weight_kg lenht_cm gest_days age_days sex :$1.;
CARDS4;
5.75 67.7 251 251 F
2.18 46.6 197 197 M
3.00 50.0 225 225 F
6.75 80.1 243 243 M
;;;;
run;

data get;
  set have;
  
  length zscore 8 wasting wastingOut $ 20;
  call missing(zscore, wasting, wastingOut);
  
  call gigs_classify_wasting(
    zscore, 
    wasting, 
    wastingOut,
    weight_kg,
    lenht_cm,
    age_days,
    gest_days,
    sex,
    0
  );
run;

---

---

gigs_classify_wfa() function

Classify weight-for-age using GIGS-recommended standards

Syntax

subroutine gigs_classify_wfa(
  zScore
, wfa $
, wfaOut $
, weight_kg
, age_days
, gest_days
, sex $
, isBirthMeasurement
);
  OUTARGS zScore, wfa, wfaOut;

---

Arguments

1. zScore - Numeric variable, of type OUTARGS, with z-score.

2. wfa - Character variable of length 20, of type OUTARGS, with classification category.

3. wfaOut - Character variable of length 20, of type OUTARGS, with classification category taking outliers into account.

4. weight_kg - Numeric variable with weight value(s) in kg.

5. age_days - Numeric variable with age in days for each child. Should be between 0 to 1856 days. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

6. gest_days - Numeric variable with gestational age(s) at birth in days between 168 and 300. By default, gigs will produce missing value(.) for out-of-bounds elements in gest_days.

7. sex - Character variable with sex, either "M" (male) or "F" (female). This argument is not case-sensitive.

8. isBirthMeasurement - Numeric variable indicating if a measurement was taken at birth.

Returns

Variables wfa and wfaOut contain weight-for-age classifications. Levels are "underweight_severe", "underweight", "normal", and "overweight". For wfaOut the list is extended by additional "outlier" value.

Note

Implausible z-score bounds are sourced from the referenced WHO report, and classification cut-offs from the DHS manual.

References

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

---

Examples

1. Weight-for-age classifications

data have;
  input weight_kg gest_days age_days sex :$1.;
CARDS4;
7.2  401 189 F
4.5  185 252 M
9.1  101 280 F
24.0 607 287 M
;;;;
run;

data get;
  set have;
  
  length zscore 8 wfa wfaOut $ 20;
  call missing(zscore, wfa, wfaOut);
  
  call gigs_classify_wfa(
    zscore, 
    wfa, 
    wfaOut,
    weight_kg,
    age_days,
    gest_days,
    sex,
    0
  );
run;

---

---

%gigs_classify_growth() macro

Macro to classify multiple growth indicators at the same time using GIGS-recommended growth standards.

This macro permits classification of multiple growth indicators (stunting, wasting, weight-for-age, and more) at once on a given data set.

Syntax

%macro gigs_classify_growth(
  dataIn,
  dataOut=WORK.RESULT,
  by =,
  gest_days=gest_days,
  age_days=age_days,
  sex=sex,
  weight_kg=weight_kg,
  lenht_cm=lenht_cm,
  headcirc_cm=headcirc_cm,
  outcomes = sfga svn stunting wasting wfa headsize,
  SfgaSvnWarn=WARNING
)/minoperator;

---

Arguments

1. dataIn - Required, name of a data set with vales to be evaluated,

• dataOut - name of a data set with result, default value is WORK.RESULT,

• by - a space separated list of variable names that give group-by processing order of the data set, default value is empty.

• gest_days - name of a numeric variable with gestational age at birth in days, default value: gest_days,

• age_days - name of a numeric variable containing age in days, default value: age_days,

• sex - name of a character variable containing sex, default value: sex,

• weight_kg - name of a numeric variable containing weight in kilograms, default value: weight_kg,

• lenht_cm - name of a numeric variable containing length/height in centimetres, default value: lenht_cm,

• headcirc_cm - name of a numeric variable containing head circumference in centimetres, default value: headcirc_cm,

• outcomes - a space-separated list of outcomes analyses to be executed on provided data, outcomes available to run are: sfga svn stunting wasting wfa and headsize.

• SfgaSvnWarn - technical parameter indicating what type of message should be displayed for "out of range" values of age days for sfga and svn outcomes. Default value: WARNING, can be replaced with NOTE, ERROR text. See Usage Note below for details.

Result

The data set created after macro execution contains the following variables created based on which outcomes are provided in the outcomes argument:

• sfga: birthweight_centile, sfga, sfga_severe,
• svn: birthweight_centile, svn,
• stunting: lhaz, stunting, stunting_outliers,
• wasting: wlz, wasting, wasting_outliers,
• wfa: waz, wfa, wfa_outliers,
• headsize: hcaz, headsize.

Usage Note

When sfga or svn outcome is used there are some additional requirements!

If a data set contains multiple observations for each subject, e.g., each value of ChildID variable has 5 observations with different measurements at different time points, then the by= parameter should be used to indicate that fact. See Examples below.

The macro will calculate birth outcomes (size-for-GA + SVN) for observations with the minimum age, where that minimum age is <3 days (provided in the &age_days macro parameter).

Typically, assessment size-for-GA or SVN categories should be done with anthropometry taken no later than 12 hours after birth (< 0.5 days). Therefore, when the age days for a 'birth' measurement is greater than 0.5, a warning is issued in the log. You can also signal this information as a NOTE or ERROR using the SfgaSvnWarn parameter.

References

WHO. Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. World Health Organisation Technical Report Series 1995, 854: 1–452

Royal College of Obstetricians and Gynaecologists. The Investigation and Management of the Small-for-Gestational-Age Fetus: Green-top Guideline No. 31. Technical report, Royal College of Obstetricians and Gynaecologists, London, 2013.

Lawn JE, Ohuma EO, Bradley E, Idueta LS, Hazel E, Okwaraji YB et al. Small babies, big risks: global estimates of prevalence and mortality for vulnerable newborns to accelerate change and improve counting. The Lancet 2023, 401(10389):1707-1719. doi: 10.1016/S0140-6736(23)00522-6

'Implausible z-score values' in World Health Organization (ed.) Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. Geneva: World Health Organization and the United Nations Children's Fund UNICEF, (2019). pp. 64-65.

'Percentage of children stunted, wasted, and underweight, and mean z-scores for stunting, wasting and underweight' in Guide to DHS Statistics DHS-7 Rockville, Maryland, USA: ICF (2020). pp. 431-435. https://dhsprogram.com/data/Guide-to-DHS-Statistics/Nutritional_Status.htm

Victora CG, Schuler-Faccini L, Matijasevich A, Ribeiro E, Pessoa A, Barros FC. Microcephaly in Brazil: how to interpret reported numbers? The Lancet 2016, 387(10019):621-624 doi: 10.1016/S0140-6736(16)00273-7

Accogli A, Geraldo AF, Piccolo G, Riva A, Scala M, Balagura G, et al. Diagnostic Approach to Macrocephaly in Children. Frontiers in Paediatrics 2022, 9:794069 doi: 10.3389/fped.2021.794069

Examples

1. Executing all analyses: sfga, svn, stunting, wasting, wfa, and headsize at once.

%gigs_classify_growth(
_tmpgigs.Life6mo
,dataOut=WORK.ANALYSIS_RESULT
,by=ID
,gest_days=gest_days
,age_days=age_days
,sex=sex
,weight_kg=wt_kg
,lenht_cm=len_cm
,headcirc_cm=headcirc_cm
)

proc print 
  data=WORK.ANALYSIS_RESULT(obs=24) 
  Label
;
run;

2. Executing only selected analyses for: sfga and headsize.

%gigs_classify_growth(
_tmpgigs.Life6mo
,dataOut=WORK.ANALYSIS_RESULT2
,by=ID
,outcomes=sfga headsize
,weight_kg=wt_kg
,headcirc_cm=headcirc_cm
)

proc print 
  data=WORK.ANALYSIS_RESULT2(obs=24) 
  Label
;
run;

3. Executing analysis for: sfga with and without BY= parameter.

data WORK.have;
  infile cards missover;
  input id $1. wt_kg gest_days age_days sex :$1.;
CARDS4;
A 2.0 280 . M
A 2.8 280 4 M
A 2.5 280 1 M
B 3.0 280 2 M
B 3.2 280 3 M
C 2.9 280 4 M
C 2.7 280 3 M
D 2.7 280 1 M
D 2.8 280 3 M
;;;;
run;
title "original data";
proc print data=WORK.have;
run;

%gigs_classify_growth(
 work.have
,dataOut=work.ANALYSIS_RESULT3
,gest_days=gest_days
,age_days=age_days
,sex=sex
,weight_kg=wt_kg
,outcomes=SFGA
,BY=id
)

title "In groups by ID";
proc print
  data=WORK.ANALYSIS_RESULT3
  Label
;
run;

%gigs_classify_growth(
 work.have
,dataOut=work.ANALYSIS_RESULT4
,gest_days=gest_days
,age_days=age_days
,sex=sex
,weight_kg=wt_kg
,outcomes=SFGA
)

title "NO groups";
proc print
  data=WORK.ANALYSIS_RESULT4
  Label
;
run;

---

---

---

License

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• a) Disclaiming warranty or limiting liability differently from the terms of sections 15 and 16 of this License; or
• b) Requiring preservation of specified reasonable legal notices or author attributions in that material or in the Appropriate Legal Notices displayed by works containing it; or
• c) Prohibiting misrepresentation of the origin of that material, or requiring that modified versions of such material be marked in reasonable ways as different from the original version; or
• d) Limiting the use for publicity purposes of names of licensors or authors of the material; or
• e) Declining to grant rights under trademark law for use of some trade names, trademarks, or service marks; or
• f) Requiring indemnification of licensors and authors of that material by anyone who conveys the material (or modified versions of it) with contractual assumptions of liability to the recipient, for any liability that these contractual assumptions directly impose on those licensors and authors.

All other non-permissive additional terms are considered “further restrictions” within the meaning of section 10. If the Program as you received it, or any part of it, contains a notice stating that it is governed by this License along with a term that is a further restriction, you may remove that term. If a license document contains a further restriction but permits relicensing or conveying under this License, you may add to a covered work material governed by the terms of that license document, provided that the further restriction does not survive such relicensing or conveying.

If you add terms to a covered work in accord with this section, you must place, in the relevant source files, a statement of the additional terms that apply to those files, or a notice indicating where to find the applicable terms.

Additional terms, permissive or non-permissive, may be stated in the form of a separately written license, or stated as exceptions; the above requirements apply either way.

8. Termination

You may not propagate or modify a covered work except as expressly provided under this License. Any attempt otherwise to propagate or modify it is void, and will automatically terminate your rights under this License (including any patent licenses granted under the third paragraph of section 11).

However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.

Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.

Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, you do not qualify to receive new licenses for the same material under section 10.

9. Acceptance Not Required for Having Copies

You are not required to accept this License in order to receive or run a copy of the Program. Ancillary propagation of a covered work occurring solely as a consequence of using peer-to-peer transmission to receive a copy likewise does not require acceptance. However, nothing other than this License grants you permission to propagate or modify any covered work. These actions infringe copyright if you do not accept this License. Therefore, by modifying or propagating a covered work, you indicate your acceptance of this License to do so.

10. Automatic Licensing of Downstream Recipients

Each time you convey a covered work, the recipient automatically receives a license from the original licensors, to run, modify and propagate that work, subject to this License. You are not responsible for enforcing compliance by third parties with this License.

An “entity transaction” is a transaction transferring control of an organization, or substantially all assets of one, or subdividing an organization, or merging organizations. If propagation of a covered work results from an entity transaction, each party to that transaction who receives a copy of the work also receives whatever licenses to the work the party's predecessor in interest had or could give under the previous paragraph, plus a right to possession of the Corresponding Source of the work from the predecessor in interest, if the predecessor has it or can get it with reasonable efforts.

You may not impose any further restrictions on the exercise of the rights granted or affirmed under this License. For example, you may not impose a license fee, royalty, or other charge for exercise of rights granted under this License, and you may not initiate litigation (including a cross-claim or counterclaim in a lawsuit) alleging that any patent claim is infringed by making, using, selling, offering for sale, or importing the Program or any portion of it.

11. Patents

A “contributor” is a copyright holder who authorizes use under this License of the Program or a work on which the Program is based. The work thus licensed is called the contributor's “contributor version”.

A contributor's “essential patent claims” are all patent claims owned or controlled by the contributor, whether already acquired or hereafter acquired, that would be infringed by some manner, permitted by this License, of making, using, or selling its contributor version, but do not include claims that would be infringed only as a consequence of further modification of the contributor version. For purposes of this definition, “control” includes the right to grant patent sublicenses in a manner consistent with the requirements of this License.

Each contributor grants you a non-exclusive, worldwide, royalty-free patent license under the contributor's essential patent claims, to make, use, sell, offer for sale, import and otherwise run, modify and propagate the contents of its contributor version.

In the following three paragraphs, a “patent license” is any express agreement or commitment, however denominated, not to enforce a patent (such as an express permission to practice a patent or covenant not to sue for patent infringement). To “grant” such a patent license to a party means to make such an agreement or commitment not to enforce a patent against the party.

If you convey a covered work, knowingly relying on a patent license, and the Corresponding Source of the work is not available for anyone to copy, free of charge and under the terms of this License, through a publicly available network server or other readily accessible means, then you must either (1) cause the Corresponding Source to be so available, or (2) arrange to deprive yourself of the benefit of the patent license for this particular work, or (3) arrange, in a manner consistent with the requirements of this License, to extend the patent license to downstream recipients. “Knowingly relying” means you have actual knowledge that, but for the patent license, your conveying the covered work in a country, or your recipient's use of the covered work in a country, would infringe one or more identifiable patents in that country that you have reason to believe are valid.

If, pursuant to or in connection with a single transaction or arrangement, you convey, or propagate by procuring conveyance of, a covered work, and grant a patent license to some of the parties receiving the covered work authorizing them to use, propagate, modify or convey a specific copy of the covered work, then the patent license you grant is automatically extended to all recipients of the covered work and works based on it.

A patent license is “discriminatory” if it does not include within the scope of its coverage, prohibits the exercise of, or is conditioned on the non-exercise of one or more of the rights that are specifically granted under this License. You may not convey a covered work if you are a party to an arrangement with a third party that is in the business of distributing software, under which you make payment to the third party based on the extent of your activity of conveying the work, and under which the third party grants, to any of the parties who would receive the covered work from you, a discriminatory patent license (a) in connection with copies of the covered work conveyed by you (or copies made from those copies), or (b) primarily for and in connection with specific products or compilations that contain the covered work, unless you entered into that arrangement, or that patent license was granted, prior to 28 March 2007.

Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law.

12. No Surrender of Others' Freedom

If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.

13. Use with the GNU Affero General Public License

Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such.

14. Revised Versions of this License

The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.

If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program.

Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.

15. Disclaimer of Warranty

THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

16. Limitation of Liability

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

17. Interpretation of Sections 15 and 16

If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.

END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

GIGS a SAS package for Guidance for International Growth Standards project.
Copyright (C) 2024 Bartosz Jablonski (yabwon@gmail.com), Simon Parker (simon.parker@lshtm.ac.uk), Linda Vesel, Eric Ohuma, Bill & Melinda Gates Foundation

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:

GIGS Package Copyright (C) 2024 Bartosz Jablonski (yabwon@gmail.com), Simon Parker (simon.parker@lshtm.ac.uk), Linda Vesel, Eric Ohuma, Bill & Melinda Gates Foundation
This program comes with ABSOLUTELY NO WARRANTY; for details type 'show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'show c' for details.

The hypothetical commands show w and show c should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.

You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see <http://www.gnu.org/licenses/>.

The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read <http://www.gnu.org/philosophy/why-not-lgpl.html>.

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