Oral nifedipine maintenance therapy after acute intravenous tocolysis in preterm labor.

Aims: Our aim was to evaluate the efficacy of maintenance oral nifedipine in pregnant women initially treated with intravenous ritodrine plus verapamil for preterm labor.

Methods: The study included 73 patients with preterm labor with intact membranes. Patients were randomized to receive either maintenance oral nifedipine therapy (n=37) administered 20 mg every six hours or no treatment (controls, n=36) after discontinuation of acute intravenous tocolysis.

Results: Compared to the control group, the mean +/- SD time gained from initiation of maintenance therapy to delivery (26.65 +/- 18.89 vs. 16.14 +/- 12.91 days, p=0.007) and the gestational age at delivery (37.03 +/- 2.06 vs. 35.1 +/- 3 weeks, p=0.003) were higher in the nifedipine maintenance therapy group. The proportion of patients who required one or more courses of subsequent intravenous therapy and perinatal outcomes were similar in the maintenance therapy and control groups.

Conclusions: The gestational age and time gained from initiation of maintenance therapy to delivery were longer in women receiving oral maintenance tocolysis with nifedipine. However, maintenance therapy did not decrease the recurrence of preterm labor episodes or improve perinatal outcomes.