Effectiveness of nifedipine versus atosiban for tocolysis in preterm labour: a meta-analysis with an indirect comparison of randomised trials


*Dr A. Coomarasamy, Education Resource Centre, Birmingham Women's Hospital, Metchley Park Road, Birmingham, B15 2TG, UK.


Objective To explore the effectiveness of nifedipine compared with atosiban for tocolysis in preterm labour.

Design A systematic review of randomised controlled trials with meta-analysis using adjusted indirect comparison.

Population Six hundred and seventy-nine women recruited in nine randomised trials evaluating the effectiveness of nifedipine versusβ-agonists, and 852 women recruited in four trials of atosiban versusβ-agonists. There were no trials comparing nifedipine directly with atosiban.

Methods We performed meta-analysis with a technique involving an adjusted indirect comparison between nifedipine and atosiban using β-agonists as the common comparator. This approach preserves the benefit accrued by randomisation in the original comparisons.

Main outcome measures Reduction in neonatal respiratory distress syndrome and delay in delivery by 48 hours.

Results Nifedipine tocolysis was associated with a significant reduction in respiratory distress syndrome compared with atosiban (OR 0.55, 95% CI 0.32–0.97). It also increased the number of women whose delivery was delayed by 48 hours (OR 1.20, 95% CI 0.73–1.95), although this result was not statistically significant.

Conclusions When indirectly compared with atosiban, nifedipine tocolysis is more effective. In the absence of a direct comparison, our analysis provides a way to explore the potential benefits of nifedipine versus atosiban.