Combined Effect of Maternal Obesity and Diabetes on Excessive Fetal Growth: Pregnancy Risk Assessment Monitoring System (PRAMS), United States, 2012–2015

•The odds of delivering a large-for-gestational-age (LGA) infant and an infant with macrosomia increased with maternal BMI.•The odds of delivering an LGA infant and an infant with macrosomia were higher if the mother had diabetes.•Those who were obese (Class III) with gestational diabetes mellitus were twice as likely to have an infant who was LGA or had macrosomia. Obesity and dysregulation in glucose metabolism are risk factors for excessive fetal growth, but their combined effects are not often examined in a single study. Data from the Centers for Disease Control and Prevention's Pregnancy Risk Assessment Monitoring System Phase 7 (2012–2015) were used. Logistic regression was used to investigate the association between maternal prepregnancy BMI and pre-existing diabetes/gestational diabetes on the odds of delivering a large-for-gestational-age infant or an infant with macrosomia. Complete data for 128,199 singleton births were used. The proportions of large-for-gestational-age infants and infants with macrosomia increased with the degree of obesity (p