Impact of a ‘rescue course’ of antenatal corticosteroids: a multicenter randomized placebo-controlled trial

Abstract

Previous studies using repetitive courses of antenatal corticosteroids (ACS) have demonstrated marginal or no benefit and concern over potential risk. No prior prospective or randomized studies have evaluated the option of a single rescue course of ACS on neonatal outcome. A multicenter randomized double-blind placebo-controlled trial was performed from May 2003 through February 2008 in 18 private (15) and university (3) medical centers. Patients with singletons or twins < 33 weeks who had completed a single course of ACS before 30 weeks and at least 14 days before inclusion, and were judged to have a recurring threat of preterm delivery in the coming week, were included. Patients were randomized to receive a single rescue course of betamethasone, 2 12-mg doses 24 hours apart, or placebo. Exclusion criteria included: premature rupture of membranes, advanced dilation (> 5 cm), chorioamnionitis, and other steroid use. In all, 437 patients were randomized (223 rescue steroid group and 214 placebo group). A total of 55% of patients in each group delivered at < 34 weeks. There was a significant reduction in the primary outcome of composite neonatal morbidity < 34 weeks in the rescue steroid group vs placebo (43.9% vs 63.6%; odds ratio, 0.45; 95% confidence interval, 0.27-0.75; P = .002) and significantly decreased respiratory distress syndrome, ventilator support, and surfactant use. Perinatal mortality and other morbidities were similar in each group. Including all neonates in the analysis (regardless of gestational age at delivery) still demonstrated a significant reduction in composite morbidity in the rescue course group (32.1% vs 42.6%, odds ratio, 0.65; 95% confidence interval, 0.44-0.97; P = .0034) and improvement in respiratory morbidities. Administration of a single rescue course of ACS before 33 weeks improves neonatal outcome without apparent increased short-term risk.