Neonatal necrotizing enterocolitis: a nine-year experience.

To gain an epidemiologic perspective on necrotizing enterocolitis (NEC), nine years' experience with 123 patients was reviewed. Mean gestational age was 31 weeks, and mean birth weight, 1,460 g; 7.3% were full-term and 10.5% were small for gestational age. Eighty infants had umbilical artery catheters, of which 50% were placed below L4-5. There was no identifiable risk factor in 11.4%; in half of these infants, NEC developed during an epidemic. Clustering of cases occurred in seven of the 108 months studied. Cases during epidemics had a lower incidence of respiratory distress syndrome. Average age at onset of NEC was 12 days; however the most common agd (mode) was 3 days, and in 13.8% onset was after the third week. On the survivors, 4% had recurrent disease one to 20 days after reinitiation of enteric feeding. The occurrence of NEC in low-risk patients and in older neonates raises serious questions about the proposed pathogenesis of NEC.