The efficacy of oral terbutaline after intravenous tocolysis

Objective: Our purpose was to investigate in a prospective, randomized study the efficacy of oral terbutaline after successful intravenous tocolysis in reducing preterm birth. Study Design: Patients between 28 and 35 weeks' gestation with uterine contractions and change in cervical examination were treated with intravenous magnesium sulfate for 12 to 24 hours. After successful tocolysis patients were approached for study participation and randomized to receive either oral terbutaline or no therapy. The dose of terbutaline was individualized to achieve a maternal pulse > 100 beats/min, and terbutaline was continued until 36 completed weeks of gestation. Recurrent preterm labor (contractions with change in cervical examination) for either group was treated with intravenous magnesium sulfate, and subsequent treatment was based on the previous randomization. RESULTS: Fifty-five patients were enrolled (28 terbutaline, 27 no oral tocolytic). No difference was found between groups with respect to time gained (4.0 ± 2.7 vs 4.6 ± 3.1 weeks, p = 0.412), gestational age at delivery (35.6 ± 2.7 vs 36.1 ± 2.4 weeks, p = 0.562), ≥37 weeks at delivery (nine vs 13, p = 0.291), recurrent preterm labor (10 vs four, p = 0.104), recurrent uterine contractions alone (five vs eight, p = 0.527), birth weight (2616 ± 633 gm vs 2645 ± 599 gm, p = 0.785), special care nursery admissions (eight vs six, p = 0.759), or neonatal respiratory distress syndrome (three vs two, p = 0.965). Conclusion: The use of oral terbutaline after successful parenteral tocolysis failed to reduce the rate of preterm birth.