The INTERGROWTH-21st Preterm Postnatal Growth Standards are robust across geographical settings and time.
21 affiliations
- 1Neonatal Special Care Unit, Regina Margherita Children Hospital, Turin, Italy. [email protected].
- 2Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK. [email protected].
- 3Center for Environmental Research and Community Health, School of Public Health, University of California, Berkeley, USA.
- 4Paris Cite University, APHP Hôpital Universitaire Necker-Enfants Malades, Paris, France.
- 5Department of Pediatrics, Federal University of Minas Gerais, Belo Horizonte, Brazil.
- 6Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK.
- 7Neonatal Intensive Care Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
- 8Neonatal Intensive Care Unit and Paediatric Department, Santa Croce Hospital, Moncalieri, Italy.
- 9Neonatology Unit, Hospital Sant Joan de Deú, Barcelona, Spain.
- 10Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Mexico City, Mexico.
- 11Division of Woman & Child Health, Dept of Paediatrics and Child Health, The Aga Khan University, Karachi, Pakistan.
- 12Division Neonatología, Hospital Materno Infantil Ramón Sarda, Buenos Aires, Argentina.
- 13The Aga Khan Hospital, Nairobi, Kenya.
- 14Department of Pediatrics, Division of Neonatology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey.
- 15Holy Family Hospital, Brong Ahafo Region, Techiman, Ghana.
- 16Neonatology Department, St. Johns Medical College Hospital, Bangalore, India.
- 17General Hospital With Extended Activity Prilep, Prilep, North Macedonia, UAE.
- 18Department of Clinical Nutrition and Dietetics, College of Health Sciences, University of Sharjah, Sharjah, UAE.
- 19Center for Obstetrics, Gynecology and Perinatology, Moscow, Russian Federation.
- 20Center for Global Child Health, Hospital for Sick Children, Toronto, Canada.
- 21Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
Abstract
We investigated the robustness of the INTERGROWTH-21st Preterm Postnatal Growth Standards for monitoring the postnatal growth of preterm infants a decade after the original study that produced them. The INTERPRACTICE-21st Study assessed the early postnatal growth of all infants born preterm in 15 study sites across 14 countries. From this sample, we selected a 'standard-like' cohort of mother-newborn dyads as in the original study. Thus, we selected all singleton babies of healthy mothers, born between 27 and < 37 weeks' gestation, without congenital malformations, fetal growth restriction or severe postnatal morbidity, i.e. confirming their eligibility for inclusion in the original standards. We used, across all study sites, the same standardised anthropometric measurements and feeding practices based on human milk. The main outcomes were the skeletal, fat-free mass indicators head circumference and length, following WHO recommendations. Variance component analysis and second-degree fractional polynomial regression models in a multi-level framework accounting for repeated measures were used to compare the growth trajectory of the 'standard-like' cohort to the standards. Of 3634 preterm babies enrolled, 1998 were singletons with complete birth anthropometric data. Among these, 1073 (54%) mother-baby dyads met the 'standard-like' eligibility criteria. The between-site differences in early postnatal growth of head circumference and length accounted for only 10.2% and 12.7% of the total variability of these repeated measures, proportions considerably lower than those for the total between individuals within a site variance of 80% and 79%, respectively. These low proportions supported pooling data across study sites and reinforced the consistency of the original results across geographical settings.Conclusion
The early growth of healthy preterm infants in the INTERPRACTICE-21st 'standard-like' cohort, assessed a decade after the original study, closely matched the pattern originally described by the INTERGROWTH-21st standards, which appear therefore robust to geographical changes and time.What is known
• The INTERGROWTH-21st Preterm Postnatal Growth Standards are the only international standards, based on the WHO prescriptive approach, for monitoring the growth of preterm infants. They were produced by following, from early pregnancy, uncomplicated preterm infants who were born to healthy mothers and achieved adequate growth and development at age 2.What is new
• In a study conducted in 14 countries worldwide, skeletal growth trajectories in a contemporary "standard-like" cohort of preterm infants demonstrated much larger within, than between, study site variance and closely matched the INTERGROWTH-21st standards, supporting the consistency of preterm growth across populations and over time.
Related
- Severe capillary leak syndrome caused by postnatal cytomegalovirus infection in a very preterm infant: a case report
- Postnatal corpus callosum microstructural deviations are linked to neurobehavioral outcomes in preterm infants.
- Early Postnatal Blood Pressure and Intraventricular Haemorrhage in Very and Extremely Preterm Neonates: A Matched Case-Control Study
- Enteral Feeding Progression Trajectories in the First Two Postnatal Weeks Are Associated with Motor Neurodevelopment at 24 Months in Preterm Infants: A Multicenter Cohort Study
- Geographical migration and fitness dynamics of Streptococcus pneumoniae: a perspective from contrasting selective pressures
BibTeX
@article{giuliani2026intergrowth21st,
title = {{The INTERGROWTH-21st Preterm Postnatal Growth Standards are robust across geographical settings and time.}},
author = {Francesca Giuliani and Robert B Gunier and Alexandre Lapillonne and Maria Albertina S Rego and Adele Winsey and Stephen A Rauch and Paola Roggero and Maria Clara Restrepo Mendez and Sonia Deantoni and Montserrat Izquierdo Renau and Irma Alejandra Coronado Zarco and Shabina Ariff and Constanza Soto Conti and Roseline Ochieng and Funda Tuzun and Jacqueline Asibey and Chandrakala Bada Shekharappa and Gabriela Tavcioska and Leila Cheikh Ismail and Camilla Menis and Irina Ryumina and Ricardo Nieto and Josephine N A Agyeman-Duah and Brenda Frias Madrid and Marina Markelova and Brenda Eskenazi and Zulfiqar A Bhutta and Aris T Papageorghiou and Stephen H Kennedy and Jose Villar},
journal = {European journal of pediatrics},
year = {2026},
month = oct,
doi = {10.1007/s00431-026-07494-1},
url = {https://europepmc.org/article/MED/42905282},
note = {CC BY},
}
RIS
TY - JOUR
TI - The INTERGROWTH-21st Preterm Postnatal Growth Standards are robust across geographical settings and time.
AU - Francesca Giuliani
AU - Robert B Gunier
AU - Alexandre Lapillonne
AU - Maria Albertina S Rego
AU - Adele Winsey
AU - Stephen A Rauch
AU - Paola Roggero
AU - Maria Clara Restrepo Mendez
AU - Sonia Deantoni
AU - Montserrat Izquierdo Renau
AU - Irma Alejandra Coronado Zarco
AU - Shabina Ariff
AU - Constanza Soto Conti
AU - Roseline Ochieng
AU - Funda Tuzun
AU - Jacqueline Asibey
AU - Chandrakala Bada Shekharappa
AU - Gabriela Tavcioska
AU - Leila Cheikh Ismail
AU - Camilla Menis
AU - Irina Ryumina
AU - Ricardo Nieto
AU - Josephine N A Agyeman-Duah
AU - Brenda Frias Madrid
AU - Marina Markelova
AU - Brenda Eskenazi
AU - Zulfiqar A Bhutta
AU - Aris T Papageorghiou
AU - Stephen H Kennedy
AU - Jose Villar
PY - 2026
DA - 2026/10/21
JO - European journal of pediatrics
DO - 10.1007/s00431-026-07494-1
UR - https://europepmc.org/article/MED/42905282
AB - We investigated the robustness of the INTERGROWTH-21st Preterm Postnatal Growth Standards for monitoring the postnatal growth of preterm infants a decade after the original study that produced them. The INTERPRACTICE-21st Study assessed the early postnatal growth of all infants born preterm in 15 study sites across 14 countries. From this sample, we selected a 'standard-like' cohort of mother-newborn dyads as in the original study. Thus, we selected all singleton babies of healthy mothers, born between 27 and < 37 weeks' gestation, without congenital malformations, fetal growth restriction or severe postnatal morbidity, i.e. confirming their eligibility for inclusion in the original standards. We used, across all study sites, the same standardised anthropometric measurements and feeding practices based on human milk. The main outcomes were the skeletal, fat-free mass indicators head circumference and length, following WHO recommendations. Variance component analysis and second-degree fractional polynomial regression models in a multi-level framework accounting for repeated measures were used to compare the growth trajectory of the 'standard-like' cohort to the standards. Of 3634 preterm babies enrolled, 1998 were singletons with complete birth anthropometric data. Among these, 1073 (54%) mother-baby dyads met the 'standard-like' eligibility criteria. The between-site differences in early postnatal growth of head circumference and length accounted for only 10.2% and 12.7% of the total variability of these repeated measures, proportions considerably lower than those for the total between individuals within a site variance of 80% and 79%, respectively. These low proportions supported pooling data across study sites and reinforced the consistency of the original results across geographical settings.Conclusion The early growth of healthy preterm infants in the INTERPRACTICE-21st 'standard-like' cohort, assessed a decade after the original study, closely matched the pattern originally described by the INTERGROWTH-21st standards, which appear therefore robust to geographical changes and time.What is known • The INTERGROWTH-21st Preterm Postnatal Growth Standards are the only international standards, based on the WHO prescriptive approach, for monitoring the growth of preterm infants. They were produced by following, from early pregnancy, uncomplicated preterm infants who were born to healthy mothers and achieved adequate growth and development at age 2.What is new • In a study conducted in 14 countries worldwide, skeletal growth trajectories in a contemporary "standard-like" cohort of preterm infants demonstrated much larger within, than between, study site variance and closely matched the INTERGROWTH-21st standards, supporting the consistency of preterm growth across populations and over time.
SN - 0340-6199
SN - 1432-1076
ER -