Antenatal Corticosteroids for the Prevention of Respiratory Distress Syndrome in Premature Twins.

Objective: To estimate whether antenatal corticosteroids before 34 weeks of gestation are associated with reduced incidence of respiratory distress syndrome (RDS) and composite neonatal morbidity in preterm twins.

Methods: This was a secondary analysis of a multicenter randomized trial for the prevention of preterm birth in multiple gestations. All liveborn, nonanomalous twins delivered between 24 0/7 and 36 6/7 weeks of gestation were included. Neonatal outcomes were compared between women who received antenatal corticosteroids and those who did not. The primary outcome was the incidence of RDS. The secondary outcome was the incidence of serious composite neonatal morbidity. Multivariable log Poisson regression with correlation adjustment between twins born to the same mother was performed for confounder control. Adjusted relative risks (RRs) are reported for study outcomes. Based on a post hoc power analysis, this study was powered to detect an RR less than 0.63 for RDS and greater than 1.43 for composite neonatal morbidity outcomes.

Results: A total of 432 women (850 neonates) were included. Only 300 (35%) neonates were born to women receiving antenatal corticosteroids. After multivariable regression, antenatal corticosteroids were not associated with a reduced incidence of RDS (81 [27%] compared with 92 [17%] neonates, adjusted RR 1.28, 95% confidence interval [CI] 0.97-1.71) or composite neonatal morbidity (87 [29%] compared with 108 [20%] neonates, adjusted RR 1.21, 95% CI 0.93-1.56). However, antenatal corticosteroids were associated with increased rates of neonatal intensive care unit admissions (235 [78%] compared with 322 [59%] neonates, adjusted RR 1.22, 95% CI 1.09-1.36) and mechanical ventilation (70 [23%] compared with 66 [12%] neonates, adjusted RR 1.52, 95% CI 1.12-2.09). Focusing analysis to newborns delivered before 34 weeks of gestation (n=311), 161 (52%) received antenatal corticosteroids. Similarly, no differences in the rate of RDS (66 [41%] compared with 68 [45%] neonates, adjusted RR 1.01, 95% CI 0.76-1.34) or composite neonatal morbidity (72 [45%] compared with 81 [54%] neonates, adjusted RR 0.95, 95% CI 0.74-1.22) were noted.

Conclusion: In this cohort of preterm twins, antenatal corticosteroid administration was not associated with a reduced incidence of RDS and composite neonatal morbidity.