Association of prematurity and neonatal infection with neurologic morbidity in very low birth weight infants

OBJECTIVE: To identify risk factors predictive of neurologic morbidity in very low birth weight (VLBW) infants. METHODS: This is a case-control study of all infants weighing 1500 g or less admitted to a single tertiary neonatal intensive care unit between April 1999 and December 2001. The case group were those neonates with neurologic morbidity including intraventricular hemorrhage, seizures, hydrocephalus, and periventricular leukomalacia. The control group were those without neurologic morbidity. Wilcoxon rank-sum, Fisher exact test, chi(2), and univariate and stepwise multiple logistic regression were performed, with P < 0.05 considered significant. RESULTS: Of 213 VLBW infants, 77 had neurologic morbidity: 61 had intraventricular hemorrhage, eight had seizures, 13 had hydrocephalus, and nine had periventricular leukomalacia. Several infants had more than one morbidity. Gestational age (odds ratio [OR] 0.95; 95% confidence interval [CI] 0.94, 0.96; P < .005), birth weight (OR 0.62; 95% CI 0.49, 0.79; P < .005), and neonatal infection (OR 1.36; 95% CI 1.17, 1.58; P < .005) were highly associated with neurologic morbidity. There was no difference in mean umbilical arterial cord pH (7.25 +/- 0.15, 7.28 +/- 0.09, P = .45) or base excess (-3.8 +/- 4.8 mEq/L, -2.3 +/- 3.0, P = .10). Only three of 52 infants (5.8%) in the case group had an umbilical arterial pH of less than 7. CONCLUSION: Prematurity and neonatal infection were the dominant factors associated with neurologic morbidity in VLBW infants. Intrapartum acidosis occurred in less than 6% of those with neurologic morbidity. ((C) 2003 by The American College of Obstetricians and Gynecologists.)