Effect of antenatal corticosteroids on respiratory morbidity in singletons after late-preterm birth

OBJECTIVE: To evaluate whether neonates born to women who previously had received antenatal corticosteroids and then delivered a late-preterm-birth neonate had less respiratory morbidity compared with those not exposed to antenatal corticosteroids. METHODS: This is a secondary analysis from a multi-center observational study regarding mode of delivery after previous cesarean delivery. We compared women who received one course of antenatal corticosteroids with unexposed parturients and evaluated various respiratory outcomes among those having a singleton, latepreterm- birth neonate. We controlled for potential confounders including gestational age at delivery, diabetes, mode of delivery, and maternal race. RESULTS: Five thousand nine hundred twenty-four patients met the inclusion criteria; 550 received steroids and 5,374 did not. In the univariable model, compared with unexposed women, those who received antenatal corticosteroids appeared more likely to have neonates who required ventilatory support (11.5% compared with 8.6%, P=.022), had respiratory distress syndrome (RDS) (17.1% compared with 12.2%, P=.001), developed transient tachypnea of the newborn (12.9% compared with 9.8%, P=.020), or required resuscitation in the delivery room (55.8% compared with 49.7%, P=.007). After controlling for confounding factors, we found no significant differences among the groups regarding all of the above outcomes with an odds ratio for RDS of 0.78 (95% confidence interval, 0.60-1.02) and ventilator support of 0.75 (95% confidence interval, 0.55-1.03). CONCLUSION: Exposure to antenatal corticosteroids does not significantly affect respiratory outcomes among those with a subsequent late-preterm birth.