Nifedipine in the management of preterm labor: a systematic review and metaanalysis.

To determine the efficacy and safety of nifedipine as a tocolytic agent in women with preterm labor. A systematic review and metaanalysis of randomized controlled trials. Twenty-six trials (2179 women) were included. Nifedipine was associated with a significant reduction in the risk of delivery within 7 days of initiation of treatment and before 34 weeks' gestation, respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage, neonatal jaundice, and admission to the neonatal intensive care unit when compared with β₂-adrenergic-receptor agonists. There was no difference between nifedipine and magnesium sulfate in tocolytic efficacy. Nifedipine was associated with significantly fewer maternal adverse events than β₂-adrenergic-receptor agonists and magnesium sulfate. Maintenance nifedipine tocolysis was ineffective in prolonging gestation or improving neonatal outcomes when compared with placebo or no treatment. Nifedipine is superior to β₂-adrenergic-receptor agonists and magnesium sulfate for tocolysis in women with preterm labor.