Objective: Our purpose was to determine whether oral terbutaline, used after successful intravenous tocolysis, will prolong pregnancy and prevent recurrent preterm labor.
Study design: After successful intravenous tocolysis, 203 women with preterm labor at 24 weeks' to 34 weeks 6 days' gestation were randomized to terbutaline (5 mg orally, every 4 hours) or placebo until 37 weeks' gestation. Women with recurrent preterm labor were treated with intravenous magnesium sulfate; if tocolysis was successful, they continued with the initial study medication. The primary outcome was the percentage delivered of their infants within 1 week of beginning oral tocolytic therapy. Latency, recurrent preterm labor, and maternal and neonatal outcomes were also assessed.
Results: Pregnancy outcome data were available in 200 women. There were no differences seen between the two groups in the incidence of delivery at 1 week (18% vs 24%, 95% confidence interval 0.44 to 1.29). In addition, there were no differences regarding median latency, mean gestational age at delivery, or the incidence of recurrent preterm labor (20% vs 16%, 95% confidence interval 0.64 to 2.71). Post hoc evaluation of 96 women enrolled before 32 weeks' gestation suggested pregnancy prolongation with maintenance oral terbutaline (p < 0.01).
Conclusions: Maintenance oral terbutaline therapy initiated at 24 weeks' to 34 weeks 6 days' gestation after successful parenteral tocolysis is not associated with pregnancy prolongation or a reduction in the incidence of recurrent preterm labor.