Distribution of gestational age at birth by maternal and infant characteristics in U.S. birth certificate data: Informing gestational age assumptions when clinical estimates are not available

• Published in: Pharmacoepidemiology and drug safety 2023-09, Vol.32 (9), p.1012-1020
• Main Authors: Margulis, Andrea V., Calingaert, Brian, Kawai, Alison T., Rivero‐Ferrer, Elena, Anthony, Mary S.
• Format: Article
• Language: English
• Subjects: Age composition; Birth Certificates; Birth weight; Births; Eclampsia; Female; Gestational Age; gestational age at birth; Humans; Infant; Infant, Low Birth Weight; Infant, Newborn; Infant, Premature; Infants; Intensive care; live birth; Male; multiple; Neonates; Population Surveillance; Pregnancy; Pregnancy Outcome; Premature Birth; preterm; Reproductive Techniques, Assisted; twin pregnancy; United States - epidemiology
• ISSN: 1053-8569; 1099-1557
• DOI: 10.1002/pds.5633

Purpose We aimed to describe the distribution of gestational age at birth (GAB) to inform the estimation of GAB when clinical or obstetric estimates are not available for perinatal pharmacoepidemiology studies. Methods We estimated GAB (median, mode, mean, and standard deviation) and percentage born at each gestational week in groups based on plurality and other variables for live births in CDC's U.S. birth data. Results In 2020, 3 617 213 newborns had birth certificates with nonmissing GAB. Among singletons (3 501 693), median and mode GAB were both 39 weeks. Births with lower median GAB were from women with eclampsia (37 weeks) or receiving intensive care (37 weeks); newborns receiving intensive care (37 weeks); newborns with birth weight