Clinical Question: Can antenatal steroids reduce the risk of respiratory distress syndrome (RDS) after an elective cesarean delivery at term?

Setting: Inpatient (any location) with outpatient follow-up

Study Design: Randomized controlled trial (single-blinded)

Allocation: Concealed

Synopsis: Antenatal steroids are known to reduce the incidence of RDS in infants born before 34 weeks’ gestation. It remains unknown whether antenatal steroids reduce RDS in babies delivered by elective cesarean at term. The investigators enrolled 942 eligible mothers with singleton pregnancies who were undergoing elective cesarean delivery planned at 37 weeks’ gestation or beyond. In the 48 hours before the procedure, the women randomly received two 12-mg intramuscular doses of betamethasone (Celestone) separated by 24 hours, or treatment as usual. Allocation to the treatment group was concealed, but individuals assessing outcomes were not blinded to group assignment. Two radiologists independently assessed chest radiographs of infants admitted for respiratory distress. Follow-up occurred for all babies until hospital discharge but not beyond.

Using intention-to-treat analysis, the incidence of admission to a special-care nursery for RDS was significantly lower in the treatment group (5.1 versus 2.4 percent; number needed to treat [NNT]= 37; 95% confidence interval [CI], 19 to 390). Although most of the RDS patients were classified as having transient tachypnea of the newborn after radiographic review, infants in the control group required significantly more prolonged and intensive hospital care, including ventilation, than infants receiving antenatal steroids (2.9 versus 0.43 percent; NNT = 40; 95% CI, 22 to 112). The predicted probability of admission at 37 weeks was 11.4 percent in the control group and 5.2 percent in the treatment group; at 38 weeks, it was 6.2 and 2.8 percent, respectively; and at 39 weeks, it was 1.5 and 0.6 percent, respectively. Wound infection and neonatal sepsis did not occur in either group.

Bottom Line: Administration of antenatal steroids 48 hours before elective cesarean delivery at 37 weeks’ gestation reduced the risk of transient tachypnea of the newborn and respiratory distress requiring prolonged hospital care. The benefit of steroids persists until 39 weeks’ gestation. Further studies in other hospital settings with longer follow-up periods will be needed before this protocol becomes the standard of care. (Level of Evidence: 1b)