INTERGROWTH21st

INTERGROWTH-21st is a multinational research project established to develop international, prescriptive standards for fetal growth, newborn size, and early postnatal growth. Initiated in the 2010s with support from the World Health Organization and a consortium of researchers, the project sought to create universal references that reflect optimal growth under healthy conditions and are applicable across populations and health systems.

Its methodology involved prospective cohorts across multiple sites using standardized protocols for dating pregnancies, performing ultrasound measurements, and collecting anthropometric data. The Fetal Growth Longitudinal Study followed healthy pregnancies with serial ultrasound assessments of fetal size parameters throughout gestation to derive a standardized growth trajectory. A complementary Newborn Size study collected measurements of weight, length, and head circumference in newborns, stratified by gestational age and sex, to generate international references for postnatal size.

Key outputs were published in The Lancet in 2014, presenting international standards for fetal size and for newborn size by gestational age and sex. The INTERGROWTH-21st standards are designed as prescriptive benchmarks of healthy growth, aiming to improve early detection of growth disturbances and to provide uniform references for clinical practice and research.

Impact and usage: since publication, the standards have influenced practice guidelines and research on perinatal growth, though adoption varies by country. The project also contributed to ongoing discussions about the universality of growth charts and the role of environmental and genetic factors in growth assessment.