Calcium channel blockers for inhibiting preterm labour; a systematic review of the evidence and a protocol for administration of nifedipine

Objective: To assess the effects on maternal, fetal and neonatal outcomes of nifedipine (and other calcium channel blockers) administered as a tocolytic agent to women in preterm labour. Methods: Standard methods of the Cochrane Collaboration and its Pregnancy and Childbirth Review Group were used. All published and unpublished randomised trials in which calcium channel blockers were used for tocolysis for women in preterm labour between 20 and 36 weeks' gestation, were considered. Main results: The systematic review includes 12 randomised controlled trials with a total of 1029 participating women. No trials were identified in which calcium channel blockers were compared with a placebo or no alternative tocolytic treatment. Calcium channel blockers appear. to be more effective than betamimetic agents in prolonging pregnancy for 7 days or longer, are much less likely to cause maternal side-effects and are associated with reduced neonatal morbidity. Conclusion: Calcium channel blockers (especially nifedipine) can be considered safer and more effective tocolytic agents than betamimetics.