Time of onset of necrotizing enterocolitis in newborn infants with known prenatal cocaine exposure.

Cocaine exposure can lead to diminished gut-blood supply and thereby contribute to the pathogenesis of necrotizing enterocolitis (NEC). Investigating the hypothesis that NEC occurs at a younger age in cocaine-exposed infants, we reviewed 1,284 neonatal intensive care admissions. Infants with NEC were divided into cocaine-exposed and cocaine-nonexposed groups, each subdivided into two birth-weight groups, using 1,500 g as the cutoff weight. Time of onset of NEC for each infant was determined and survival curves for the cocaine-exposed and nonexposed groups were calculated using their birth-weight subdivision. Hazard function curves were done. Neonatal risk factors in both groups were compared. Twelve percent (28/231) of cocaine-exposed infants developed NEC stage II or III versus 3% (34/1053) in the nonexposed group (P < 0.05). Eight percent of cocaine-exposed and 2% of nonexposed survivors had NEC by day 7 versus 20% and 5% by day 28 after birth (P < 0.05). Infants > 1,500 g were at risk for NEC until day 8 only, whereas infants < or = 1,500 g had both an early and continuing risk for NEC with a biphasic pattern of onset. The accentuated peak in early-onset NEC may be attributed to antenatal cocaine exposure, while late-onset NEC in the < or = 1,500 g group probably relates to a variety of pathogenetic factors.