Abstract

OBJECTIVE: We aimed to compare the prevalence and neonatal mortality associated with large for gestational age (LGA) and macrosomia among 115.6?million live births in 15 countries, between 2000 and 2020. DESIGN: Population-based, multi-country study. SETTING: National healthcare systems. POPULATION: Liveborn infants. METHODS: We used individual-level data identified for the Vulnerable Newborn Measurement Collaboration. We calculated the prevalence and relative risk (RR) of neonatal mortality among live births born at term?+?LGA (>90th centile, and also >95th and >97th centiles when the data were available) versus term?+?appropriate for gestational age (AGA, 10th-90th centiles) and macrosomic (?4000, ?4500 and ?5000?g, regardless of gestational age) versus 2500-3999?g. INTERGROWTH 21st served as the reference population. MAIN OUTCOME MEASURES: Prevalence and neonatal mortality risks. RESULTS: Large for gestational age was common (median prevalence 18.2%; interquartile range, IQR, 13.5%-22.0%), and overall was associated with a lower neonatal mortality risk compared with AGA (RR?0.83, 95%?CI 0.77-0.89). Around one in ten babies were ?4000?g (median prevalence 9.6% (IQR 6.4%-13.3%), with 1.2% (IQR 0.7%-2.0%) ?4500?g and with 0.2% (IQR 0.1%-0.2%) ?5000?g). Overall, macrosomia of ?4000?g was not associated with increased neonatal mortality risk (RR?0.80, 95%?CI 0.69-0.94); however, a higher risk was observed for birthweights of ?4500?g (RR?1.52, 95%?CI 1.10-2.11) and ?5000?g (RR?4.54, 95%?CI 2.58-7.99), compared with birthweights of 2500-3999?g, with the highest risk observed in the first 7?days of life. CONCLUSIONS: In this population, birthweight of ?4500?g was the most useful marker for early mortality risk in big babies and could be used to guide clinical management decisions. © 2023 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.