Maternal body mass index and necrotizing enterocolitis: A case-control study.

Introduction: Our aim was to determine if maternal body mass index (BMI) is associated with necrotizing enterocolitis (NEC) in a large urban delivery center.

Methods: This single center retrospective case-control study included 291 infants under gestational age of 33 weeks admitted to the neonatal intensive care unit (NICU) during a 10-year period. Cases of stage 2 and 3 NEC were matched at a ratio of 2 controls (n = 194) to 1 case (n = 97). Maternal BMI was categorized as normal (≤24.9), overweight (25-29.9) and obese (≥30). Chi-square and stepwise logistic regression were used for analysis. A power analysis was performed to determine if sample size was sufficient to detect an association.

Results: Stepwise logistic regression demonstrated no association between NEC and maternal obesity. Maternal hypertension, pre-eclampsia, premature rupture of membranes, maternal exposure to antibiotics, placental abruption and gestational diabetes were not associated with NEC. Power analysis showed the sample size was sufficient to detect an association of NEC with maternal BMI in three groups analyzed. In this case-control study, there was an association between NEC and maternal overweight but not obesity at delivery.

Discussion: Our results did not show a significant association of NEC with maternal obesity. The percent of overweight and obese mothers prior to pregnancy and at delivery was significantly higher in our population than the national average and may be responsible for the limited ability to reveal any association between maternal obesity and NEC.