Effectiveness of nifedipine tocolysis to facilitate external cephalic version: a systematic review.

The success rates of external cephalic version (ECV) are improved with the use of betamimetic tocolytics, but these drugs are associated with maternal side effects. To critically evaluate the effectiveness and advantages, if any, of nifedipine as a tocolytic for ECV. We searched PubMed, OVID [Medline, all evidence-based medicine (EBM) reviews], Embase, the Cochrane clinical trials register and references therein. Randomised trials comparing nifedipine with placebo or another tocolytic agent among women with a singleton, term breech or transverse presentation. Two reviewers evaluated search results and extracted data from eligible studies using a standard data extraction form. Primary outcomes were success rates of ECV and cephalic presentation at delivery. Pooled relative risks and 95% confidence intervals were calculated for comparable studies, and where similar outcomes were assessed. Three trials met the inclusion criteria. Two trials (n = 176) compared nifedipine with terbutaline and found lower rates of successful ECV among women receiving nifedipine, pooled risk ratio = 0.67 (95% CI 0.48-0.93, P = 0.016). One trial (n = 320) comparing nifedipine with placebo did not find any significant difference in ECV success rates (41.6% nifedipine versus 37.2% placebo, P = 0.43). Although minor side effects were slightly higher with nifedipine compared with placebo, there was no significant difference in the rate of adverse maternal or neonatal outcomes or maternal satisfaction between the nifedipine and terbutaline groups, and women in both groups showed a similar preference for oral administration (62% nifedipine and 71% terbutaline). This review found no evidence to support the use of nifedipine for tocolysis to facilitate external cephalic version.