gigs: A package for standardizing fetal, neonatal, and child growth assessment with extensions to egen

In this article, we describe gigs , the Guidance for International Growth Standards package for Stata. gigs contains multiple egen functions for converting between fetal biometry or anthropometric measurements and z scores or centiles in both the World Health Organization child growth standards and the INTERGROWTH-21st standards. We also describe an additional Stata command that wraps these functions to provide growth outcome classification for newborns and infants up to five years of age using a suite of international growth standards. Clear and consistent commands with the functionality described in this article have not been available to Stata users prior to the release of this article. These features will be instrumental for standardizing methods for growth assessment in fetal, newborn, and child health research, as well as implementation, clinical practice, and population-level comparisons.