Influence of the interval between antenatal corticosteroid therapy and delivery on respiratory distress syndrome.

AimIn spite of the recommendation for rescue antenatal corticosteroids (ACS), the optimal time interval between primary and rescue courses has not been clearly demonstrated. The aim of this study was to determine the effects of the interval between a single ACS course and delivery on the incidence of respiratory distress syndrome (RDS). MethodsIn this retrospective study, we included singleton pregnant women who received a single course of ACS and delivered beyond 48 h after ACS administration between 24 and 33 weeks' gestation. The risk of RDS was compared between patients who delivered within seven days (Group I), 7-14 days (Group II) and beyond 14 days (Group III) after ACS administration. ResultsWe included 83, 14 and 20 patients in Groups I, II and III, respectively. After adjusting for confounders, the ACS delivery interval was significantly associated with RDS in Group II (adjusted odds ratio 12.8, 95% confidence interval 1.31-164.7) and Group III (adjusted odds ratio 64.0, 95% confidence interval 1.32-5808.6). ConclusionA longer ACS delivery interval is associated with a higher risk of RDS. Thus, the use of a rescue course could be expected to reduce the incidence of RDS in patients beyond seven days after ACS administration who remain at risk for preterm delivery within seven days, especially in cases of placenta previa and/or women bearing a male fetus.