Objective: To assess the effects of multiple courses of antenatal corticosteroids on perinatal and neonatal death and neonatal, infant, and maternal disease.
Methods: MEDLINE and Embase were searched for human studies published in English. Studies that compared multiple courses of antenatal corticosteroids versus a single course were included if they were published in full and were controlled for gestational age at birth. Meta-analyses (odds ratio and 95% confidence interval) were undertaken when possible.
Results: Eight observational studies were included. Selection bias was present in all studies. Multiple courses of antenatal corticosteroids were associated with a decreased risk of respiratory distress syndrome (odds ratio, 0.79; 95% confidence interval, 0.64 to 0.98) and patent ductus arteriosus (odds ratio, 0.56; 95% confidence interval, 0.35 to 0.90) and were associated with an increased risk of endometritis (odds ratio, 3.42; 95% confidence interval, 1.92 to 6.11). There was no significant effect on other neonatal and maternal outcomes.
Conclusion: It is not possible to establish the true effects of multiple courses of antenatal corticosteroids by a review of the results of observational studies because of the effect of confounding variables. Randomized controlled trials are needed to address this important issue.