Morbidity and mortality among very-low-birth-weight neonates with intrauterine growth restriction

OBJECTIVE: We sought to determine the associations between intrauterine gro wth restriction and neonatal morbidity and mortality, as well as the impact of prenatal glucocorticoid administration on the frequency of specific com plications of prematurity among neonates with intrauterine growth restricti on. STUDY DESIGN: We examined the association between intrauterine growth restr iction and adverse neonatal outcomes in a population of 19,759 singleton ve ry-low-birth-weight neonates without major birth defects. We included neona tes from 25 to 30 weeks' gestation entered in the Vermont Oxford Network da tabase between 1991 and 1996 by 196 institutions. Intrauterine growth restr iction was defined as the 10th percentile for birth weight according to the 1993 US national statistics. Odds ratios were estimated according to stepw ise logistic regression for each neonatal outcome. Potential explanatory va riables included gestational age, intrauterine growth restriction, race, pr enatal care, prenatal glucocorticoid administration, route of delivery, fet al sex, and birth within versus postnatal transfer to a network institution . RESULTS: There was a statistically significant association of intrauterine growth restriction with neonatal death (odds ratio, 2.77; 95% confidence in terval, 2.31-3.33), necrotizing enterocolitis (odds ratio, 1.27; 95% confid ence interval, 1.05-1.53), and respiratory distress syndrome (odds ratio, 1 .19; 95% confidence interval, 1.03-1.36). There was a trend (P <.10) toward association of intrauterine growth restriction with increased risks of int raventricular hemorrhage (odds ratio, 1.13; 95% confidence interval, 0.99-1 .29) and severe intraventricular hemorrhage (grades III and IV; odds ratio, 1.25; 95% confidence interval, 0.98-1.59). Maternal prenatal glucocorticoi d administration was associated with significantly lower risks of respirato ry distress syndrome (odds ratio, 0.51; 95% confidence interval, 0.44-0.58) , intraventricular hemorrhage (odds ratio, 0.67; 95% confidence interval, 0 .61-0.73), severe intraventricular hemorrhage (odds ratio, 0.50; 95% confid ence interval, 0.43-0.57), and death (odds ratio, 0.54; 95% confidence inte rval, 0.48-0.62). The benefits of prenatal glucocorticoid therapy for growt h-restricted newborns were similar to those among normally grown infants. CONCLUSIONS: Intrauterine growth restriction within the range of 501 to 150 0 g birth weight is associated with increased risks of neonatal death, necr otizing enterocolitis, and respiratory distress syndrome. Prenatal corticos teroid use was associated with decreased risks of all outcomes studied exce pt necrotizing enterocolitis. We found no evidence that this benefit was de pendent on fetal size.