Gestational age–specific risks vs benefits of multicourse antenatal corticosteroids for preterm labor

Objective The purpose of this study was to estimate a gestational age threshold at which the benefits of treatment with weekly courses of antenatal corticosteroids (ACS) during preterm labor outweigh the risks. Study Design Risk-benefit ratios by gestational age were determined with the use of a Markov microsimulation decision-analysis model with a 1-week cycle length. Single course and multiple (weekly to a maximum of 4) courses of ACS by gestational age of entry (23 weeks to 31 weeks 6 days' gestation) were compared. Benefits were composite events (respiratory distress syndrome, chronic lung disease, severe intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia, or stillbirth) averted. Risks were small head circumference and small for gestational age. Results More composite events are averted (benefits) than risks acquired (ratio, 6:1) when multiple courses of ACS are initiated at 26 weeks' gestation. When multiple courses of ACS are initiated at 29 weeks' gestation, the risk-benefit ratio is 1. Beyond 29 weeks, there is a suggestion of more risk than benefit. Conclusion The model suggests that multiple courses of ACS that are initiated at