Objective: To determine an optimal timing strategy for rescue corticosteroids in gravidas with preterm prelabor rupture of membranes (PPROM) prior to 33 0/7 weeks.
Methods: This was a retrospective cohort analysis of 109 gravidas with a singleton gestation and PPROM between 23 0/7 and 32 6/7 weeks who delivered at a single inner city tertiary care center. The time of the actual first dose of corticosteroids was chosen as Time 0. The date and time of labor onset, chorioamnionitis, heavy bleeding, cord prolapse, or fetal heart rate decelerations warranting delivery were recorded, as well as the date and time of delivery. We then compared hypothetical timing strategies for administration of the rescue course of corticosteroids at either 1, 2, or 3 weeks after the first course if still undelivered, compared to a strategy of withholding the rescue course until the recognition of spontaneous labor or the need for delivery. For each strategy, we calculated the percentage of gravidas who would have delivered within the optimal window after rescue course corticosteroids, defined as delivery at 24 h to 7 days from the first rescue dose.
Results: The median time from PPROM to delivery among the 109 gravidas was 8.9 days (interquartile range 4.4-17.9 days). Forty-eight (44%) gravidas delivered within the first week after initial corticosteroid administration, leaving 61 (56%) eligible for a rescue dose. In our hypothetical models, the strategy of giving rescue corticosteroids at either 1, 2, or 3 weeks from the first course would have resulted in 34.4%, 23.0%, and 19.7% of infants being born at 24 h to 7 days after the first rescue dose, respectively. These differences among the three groups or between any two groups were not statistically significant. However, all fixed interval strategies were statistically superior to the strategy of waiting for spontaneous labor or the need for delivery, in which only 4.9% would have delivered within the optimal window.
Conclusion: In gravidas with PPROM prior to 33 0/7 weeks, giving rescue corticosteroids at a fixed interval of either 1, 2, or 3 weeks after the first course would result in a greater percentage of infants being born within the optimal 24 h to 7 day window compared to administering the rescue course at the onset of labor, infection, bleeding, or abnormal fetal heart rate tracing.
Keywords: Preterm prelabor rupture of membranes; antenatal corticosteroids; latency period; rescue corticosteroids.