Neonatal necrotizing enterocolitis an epidemiological study.

Necrotizing enterocolitis (NEC) was diagnosed in 77 infants among 2200 admissions to the NICU during the period January 1986 to September 1990. The incidence was 0.5% of all live births and 3.5% of NICU admissions. Majority (57.1%) had Stage I of the disease while 23.4% had Stage II and 19.5% had Stage III of the disease. The average birth weight of the babies was 1650 +/- 577 g and gestational age 33.3 +/- 2.6 weeks. Majority (53.2%) were very low birth weight (VLBW) babies. Incidence was significantly more (5.7% vs 0.25%, p < 0.001) in VLBW infants and in preterm infants of gestational age less than 32 weeks (5.2% vs 0.09%, p < 0.001). Multiple risk factors were present in these babies while 8 babies did not have any risk factor. Risk of developing NEC was significantly more if infants had any of these risk factor (p < 0.001). Incidence of severe birth asphyxia was more in Stage I cases (35.7% vs 10.3%, p < 0.05). The age at presentation was 4.9 +/- 4.8 days and majority (96%) presented during the first 14 days. The overall survival was 61% and was 70.5, 77.8 and 13.3% in Stages I, II and III, respectively. VLBW and preterm infants had a higher mortality.