Morbidity and Mortality are Increased in Growth Restricted Very Low Birth Weight Newborns † 1209

Abstract

The association of growth restriction with neonatal morbidity and mortality is uncertain. We sought to determine if: 1) growth restriction (IUGR) is associated with an altered risk of neonatal morbidity and mortality and 2) antenatal glucocorticoid administration modifies the risk of morbidity or mortality associated with IUGR We examined the association of IUGR with the risk of death, respiratory distress syndrome (RDS), necrotizing enterocolitis(NEC), intraventricular hemorrhage (IVH) and severe IVH (grades 3 and 4) using the Vermont Oxford Network Database. The Database includes infants with birth weights between 501 and 1500 grams, who are either born at or admitted to participating centers within 28 days of birth. Between 1991 and 1996, 19,761 singleton caucasian and African-american infants between 25 and 30 weeks, inclusive, without major birth defects were entered in the Database by 196 participating North American institutions. IUGR was defined as birth weight below the tenth percentile based on U. S. Center for Health Statistics 1993 Natality data which are both race and gender specific. Analyses were performed using stepwise logistic regression, adjusted for clustering, for each of the outcomes, with potential explanatory variables including gestational age, IUGR, race, prenatal care, prenatal steroid use, route of delivery, gender, and inborn/outborn status. IUGR was associated with an increased risk of neonatal death (odds ratio (OR) 2.77, 95% confidence intervals (CI) 2.31-3.33)), NEC (OR 1.27 CI 1.05-1.53) and RDS (OR 1.19 CI 1.03-1.36). There was an association of IUGR with IVH (OR 1.13 CI 1.00-1.29), and severe IVH (OR 1.25 CI 0.98-1.60), but these associations were not significant at P<0.05. Prenatal steroids were associated with a reduction in the risk of RDS (OR 0.51 CI 0.44-0.58), IVH (OR 0.67 CI 0.61-0.73), severe IVH (OR 0.50 CI 0.43-0.57) and death (OR 0.54 CI 0.48-0.62). These benefits were observed regardless of race or growth restriction. We conclude that IUGR is associated with an increase in the risk of neonatal death, NEC and RDS for infants with birth weights of 501 and 1500 grams. Prenatal steroid use was associated with a decrease in the risk of all outcomes studied except NEC for both normally grown and growth restricted infants.