Value of antenatal corticosteroid therapy in preterm birth.

This prospective observational study was designed to evaluate the magnitude of the corticosteroid-related reduction in the risk of respiratory distress syndrome (RDS), intraventricular hemorrhage and neonatal death according to different etiologic subgroups of preterm delivery. Of 380 patients delivered before 35 weeks' gestation, 155 received a complete course of dexamethasone or betamethasone to promote fetal lung maturation. In logistic models, the steroid-related reduction of RDS was greater among patients with intact membranes as opposed to patients with premature rupture of membranes (excess risk = 0.31; 95% confidence interval (C.I.) = 0.13-0.73; P = 0.007) and in patients with spontaneous preterm labor as compared with other etiologic groups (excess risk = 0.33; 95% C.I. = 0.11-0.98, P = 0.04). On the other hand, the steroid-related reduction of severe (grade III-IV) intraventricular hemorrhage was more marked in growth retarded as opposed to well-grown fetuses (excess risk = 0.15; 95% C.I. = 0.03-0.96, P = 0.04), and in planned as compared with spontaneous preterm deliveries (excess risk = 0.15; 95% C.I. = 0.03-0.96, P = 0.04). Results show that the greatest benefit from antenatal steroids appears to be in preterm deliveries with intact membranes and in planned preterm deliveries.