title: Effectiveness of nifedipine tocolysis to facilitate external cephalic version: a systematic review.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To critically evaluate the effectiveness and advantages, if any, of nifedipine as a tocolytic for ECV.
  
  
  METHODS
  We searched PubMed, OVID [Medline, all evidence-based medicine (EBM) reviews], Embase, the Cochrane clinical trials register and references therein.
  
  
  METHODS
  Randomised trials comparing nifedipine with placebo or another tocolytic agent among women with a singleton, term breech or transverse presentation.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  This review found no evidence to support the use of nifedipine for tocolysis to facilitate external cephalic version.
authors.affiliation: Perinatal Research, Kolling Institute of Medical Research, University of Sydney, Australia.
authors.forename: C B
authors.initials: CB
authors.lastname: Wilcox
authors.forename: N
authors.initials: N
authors.lastname: Nassar
authors.forename: C L
authors.initials: CL
authors.lastname: Roberts
mesh_terms: D001946:Breech Presentation / Q000188:drug therapy*; D005260:Female; D006801:Humans; D009543:Nifedipine / Q000627:therapeutic use*; D011247:Pregnancy; D011256:Pregnancy Outcome; D016032:Randomized Controlled Trials as Topic; D015149:Tocolytic Agents / Q000627:therapeutic use*; D014710:Version, Fetal / Q000379:methods*
chemical_list: D015149:Tocolytic Agents; D009543:Nifedipine