In-hospital mortality and morbidity among extremely preterm infants in relation to maternal body mass index

Objective The objective of this paper is to compare in-hospital survival and survival without major morbidities in extremely preterm infants in relation to maternal body mass index (BMI). Methods This retrospective cohort study included extremely preterm infants (gestational age 22(0/7)-28(6/7)weeks). This study was conducted at National Institute of Child Health and Human Development Neonatal Research Network sites. Primary outcome was survival without any major morbidity. Results Maternal BMI data were available for 2415 infants. Survival without any major morbidity was not different between groups: 30.8% in the underweight/normal, 28.1% in the overweight, and 28.5% in the obese (P = 0.65). However, survival was lower in the obese group (76.5%) compared with overweight group (83.2%) (P = 0.02). Each unit increase in maternal BMI was associated with decreased odds of infant survival (P < 0.01). Conclusions Survival without any major morbidity was not associated with maternal obesity. An increase in maternal prepregnancy BMI was associated with decreased odds of infant survival.