- The purpose of this study was to compare complications and outcome of preterm neonates weighing < or =1,500 g who developed necrotizing enterocolitis (NEC) to neonates without NEC. During January, 1995 to December, 1998, 211 live preterm neonates were born with birth weight < or =1,500 g. A cross sectional prospective study was designed and two groups were defined: 17 neonates who developed NEC and 194 without NEC. Multiple logistic regression analysis was performed to determine independent risk factors for the development of NEC. The prevalence of NEC was 8% (17/211). The following complications were found to be significantly higher among mothers of neonates with NEC: mild pre-eclampsia (11.8 vs. 2.6%, p=0.04); severe pre-eclampsia (35.5 vs. 12.9%, p=0.01); chronic hypertension (29.4 vs. 5.7%, p<0.001) and low birth weight (968 +/- 233 vs. 1,123 +/- 257 g, p=0.02). In contrast, mean maternal age, mean gestational age at delivery and parity were not significantly different between the groups. A multivariate analysis including the following factors: maternal hypertensive disorders, pregestational diabetes mellitus, birth weight and gestational age at delivery, found only maternal hypertensive disorders to be independent risk factors for NEC (OR=5.21, 95% CI 1.64-16.58). Maternal hypertension is an independent risk factor for the development of NEC in preterm neonates weighing <1,500 g. Thus, maternal vascular disorders may play an important role in the pathophysiology of NEC.