Is there justification for using indomethacin in preterm labor? an analysis of neonatal risks and benefits

OBJECTIVE: Recent reports have suggested that the use of indomethacin for tocolysis may independently increase the risk for major adverse neonatal events, such as intraventricular hemorrhage and necrotizing enterocolitls. The objective of this study was to determine if this potential risk of indomethacin is outweighed by the benefit of delivery delay at gestational ages less than 32 weeks. STUDY DESIGN: We constructed separate decision trees to compare strategies of tocolysis with indomethacin versus no tocolysis for hypothetical cohorts of patients presenting with idiopathic preterm labor at 24, 26, 28, 30, and 32 weeks gestation. Probabilities for these decision models, including estimates of indomethacin efficacy and the potential for increase in adverse neonatal events with indomethacin were obtained from the medical literature. The primary outcome was the number of expected adverse neonatal events per 1000 women for each strategy at each gestational age. RESULTS: Number of Expected Adverse Neonatal Events per 1000 Women Gestational Age Indomethacin No Indomethacin 24 weeks 616 768 26 weeks 516 640 28 weeks 373 495 30 weeks 221 374 32 weeks 129 211 Across gestational ages, the strategy of tocolysis with indomethacin consistently yielded a lower expected number of adverse neonatal events. These results were insensitive to the probabilities used in the model. CONCLUSIONS: Based on current estimates, the benefits of indomethacin outweigh the potential risks to the neonate at gestational ages less than or equal to 32 weeks. Thus, the use of indomethacin for tocolysis at these ages is reasonable strategy.