Intrauterine growth restriction in very low birth weight newborns: Neonatal outcome

OBJECTIVE: To determine if: 1) intrauterine growth restriction (IUGR) is associated with an increased or decreased risk of neonatal morbidity and mortality when controlling for potential confounding variables; 2) antenatal steroid use is associated with a reduction in morbidity or mortality in IUGR. STUDY DESIGN: We examined the association of intrauterine growth restriction (IUGR) with the risk of death (prior to discharge), respiraton distress syndrome (RDS), necrotizing enterocolitis (NEC). intraventricular hemorrhage (IVH) and severe intraventricular hemorrhage (SIVH) (grades 3 and 4) using the Vermont Oxford Neonatal Network Database. The Network includes data for infants with birth weights between 501 and 1500 grams, who are either born at or admitted to then center within 28 days of birth. Between 1991 and 1995, 10,084 singleton, Caucasian infants between 25 and 30 weeks gestation, inclusive, without birth defects were entered in the Database by 150 participating institutions. IUGR was defined by the Canadian national statistics (Arbuckle) which are both race and gender specific. Analyses were performed using logistic regression for each of the outcomes. with potentially explanatory variables including gestational age, IUGR, prenatal care, prenatal steroid use, route of delivery, gender, and inborn/outborn status. P<0.05 was accepted for significance. RESULTS: There was an association of IUGR with an increased risk of neonatal death (odds ratio (OR) 2.24 95% confidence limit (1.87-2.69)), and NEC (OR 1.38, (1.11-1.71)) and no impact of IUGR on the risk of IVH (OR 1.04 (0.88-1.22). SIVH (OR 1.01 (0.82-1.24) or RDS (OR 1.09 (0.93-1.28)). Prenatal steroid use was associated with a significant reduction in the risk of RDS (OR 0.62 (0.43-0.89)), IVH (OR 0.74 (0.64-0.85)), severe IVH (OR 0.57 (0.48-0.67)) and death (OR 0.54 (0.46-0.65)). This benefit was independent of IUGR. CONCLUSIONS: Fetal growth restriction appears to be associated with an increase in the risk of neonatal death and NEC. We found no change in the risk of IVH or RDS. Prenatal steroid use was associated with a decrease in the risk of all outcomes studied except NEC. There was no evidence that this effect was influenced by IUGR.