Administration of corticosteroids at least 24 hours before delivery is associated with a decreased risk of respiratory distress syndrome (RDS), intraventricular hemorrhage, and neonatal mortality in preterm infants. However, the effectiveness of corticosteroids when delivery occurs within 24 hours of corticosteroid administration is unclear. Elimian and colleagues studied the effect of corticosteroid administration close to delivery on perinatal morbidity and mortality.

The authors reviewed data from 229 infants born at 23 to 34 weeks’ gestation between 1998 and 2002 at a university teaching hospital. No antenatal corticosteroids were given to 104 infants, and 125 infants were exposed to only one 12-mg dose of betamethasone. The steroid-exposed infants had significantly lower gestational age at delivery (28.4 weeks compared with 29.7 weeks) and longer admission to delivery interval (4.6 hours compared with 1.1 hours) than noncorticosteroid-exposed infants. Steroid-exposed infants also had lower birth weights (1,189 g [2 lb, 10 oz] compared with 1,289 g [2 lb, 13 oz]), but this difference did not reach statistical significance. The two groups did not differ in rates of chorioamnionitis, Apgar scores, and use of surfactant or vasopressor therapy in the neonatal period. Bronchopulmonary dysplasia was significantly more common in steroid-exposed infants (36.8 percent compared with 16.3 percent), but the groups did not differ in rates of RDS, intra-ventricular hemorrhage, necrotizing enterocolitis, patent ductus arteriosus, retinopathy, sepsis and neonatal mortality. Logistic regression was used to adjust outcomes for gestational age. After adjustment, infants who received one dose of betamethasone had significant reductions in neonatal mortality rates (odds ratio [OR], 0.31), intraventricular hemorrhage (OR, 0.42), and need for vasopressor therapy (OR, 0.35). Adjustment did not reveal any differences between the groups in the other outcomes monitored.

The authors conclude that an incomplete course of antenatal corticosteroids has benefits for premature infants. They believe the higher rate of bronchopulmonary dysplasia could be explained by the differences in gestational age and greater lung immaturity in the treated group.