Weekly prenatal steroids reduce birthweight

Weekly doses of prenatal steroids do not improve overall outcome and are associated with lower birthweight and smaller size for gestational age compared to a single dose, according to a study published in the September issue of the American Journal of Obstetrics & Gynecology.

Ronald J. Wapner, MD, of Columbia University College of Physicians and Surgeons in New York, and colleagues conducted a study of women between 23 and 32 weeks' gestation who had received one course of steroids 7 to 10 days earlier, with a view to randomizing 2,400 women to receive weekly betamethasone or placebo.

The independent data and safety monitoring committee terminated the study when 495 women were enrolled, because although the repeated doses of steroids significantly reduced administration of neonatal surfactants, mechanical ventilation, and pneumothoraces, they did not significantly reduce composite primary morbidity. They were also associated with lower birthweight and an increased number of infants who were small for gestational age.

Wapner RJ, Sorokin Y, Thom EA, et al. Single versus weekly courses of antenatal corticosteroids: evaluation of safety and efficacy. Am J Obstet Gynecol. 2006;195,633-642.