Do repeat doses of antenatal corticosteroids reduce complications?

Women who remain at risk for very preterm birth 7 or more days after an initial course of corticosteroids should receive repeat doses to reduce neonatal morbidity, according to the findings of a recent hospital-based, randomized, controlled trial.

Almost 1,000 women who remained at risk for preterm birth at less than 32 weeks' gestation 1 week or more after receiving an initial course of prenatal corticosteroids were randomly assigned to receive either a repeat intramuscular (11.4 mg) dose of betamethasone or saline placebo. This was repeated every week the women remained undelivered.

Compared with the placebo group, fewer babies in the corticosteroid group had respiratory distress syndrome (41% vs. 33%, RR 0.82, 95% CI; 0.71–0.95) or severe lung disease (20% vs. 12%; RR 0.60, 95% CI; 0.46–0.79). In addition, they required less oxygen therapy and mechanical ventilation.

The authors of the editorial also question the necessity of repeated weekly administration of corticosteroids in babies delivered after 34 weeks' gestation, as were nearly 35% of those in the study. They assert that the outcomes of these babies are more favorable whether they are given one dose or 10 of betamethasone. They suggest an alternative strategy of only giving a subsequent dose of corticosteroid when confronted with the necessity of delivery and then stalling uterine activity for 24 to 48 hours after corticosteroid administration.

Crowther CA, Haslam RR, Hiller JE, et al. Neonatal respiratory distress syndrome after repeat exposure to antenatal corticosteroids: a randomised controlled trial. Lancet. 2006;367:1913-1919.

Montan S, Arulkumaran S. Neonatal respiratory distress syndrome. Lancet. 2006;367:1878-1879.