Single vs weekly courses of antenatal corticosteroids for women at risk ofpreterm delivery - A randomized controlled trial

Context The practice of administering weekly courses of antenatal corticost eroids to pregnant women at risk of preterm delivery is widespread, but no randomized trial has established the efficacy or safety of this practice. Objectives To evaluate the efficacy of weekly administration of antenatal c orticosteroids compared with a single course in reducing the incidence of n eonatal morbidity and to evaluate potential complications of weekly treatme nt. Design and Setting Randomized, double-blind, placebo-controlled intention-t o-treat trial conducted in 13 academic centers in the United States from Fe bruary 1996 through April 2000. Participants A total of 502 pregnant women between 24 and 32 completed week s' gestation who were at high risk of preterm delivery. Intervention All patients received a complete single course of antenatal co rticosteroids (either betamethasone, 12 mg intramuscularly repeated once in 24 hours for 2 doses, or dexamethasone, 6 mg intramuscularly repeated ever y 12 hours for 4 doses). Participants who had not delivered 1 week after re ceipt of the single course were randomly assigned to receive either betamet hasone, 12 mg intramuscularly repeated once in 24 hours for 2 doses every w eek until 34 weeks' gestation or delivery, whichever came first (n=256), or a similarly administered placebo (n=246). Main Outcome Measure Composite neonatal morbidity (including severe respira tory distress syndrome, bronchopulmonary dysplasia, severe intraventricular hemorrhage, periventricular leukomalacia, proven sepsis, necrotizing enter ocolitis, or perinatal death). Results Composite morbidity occurred in 22.5% of the weekly-course group vs 28.0% of the single-course group (unadjusted relative risk, 0.80; 95% conf idence interval, 0.59-1.10). Neither group assignment nor the number of tre atment courses was associated with a reduction in composite morbidity. Conclusions Weekly courses of antenatal corticosteroids did not reduce comp osite neonatal morbidity compared with a single course of treatment. Weekly courses of antenatal corticosteroids should not be routinely prescribed fo r women at risk of preterm delivery.