Repetitive Antenatal Corticosteroids: More Harm Than Good?

In several randomized trials, researchers have confirmed that a single antenatal course of corticosteroids lowers risks for respiratory distress syndrome, intraventricular hemorrhage, and neonatal death in preterm infants. The MACS trial, the largest randomized trial of antenatal steroid use to date, was designed to test the benefits of multiple courses of antenatal steroids administered every 14 days. More than 1850 women in 20 countries, who remained at high risk for preterm delivery after initial courses of antenatal steroids, were assigned randomly to receive two injections, 24 hours apart, of betamethasone or placebo every 14 days until 33 weeks’ gestation or delivery. The primary outcome was a composite of perinatal and neonatal morta…