Effect of terbutaline on premature labor. A double-blind placebo-controlled study

The effect of terbutaline, a "selective" beta2-receptor stimulator, was compared with that of placebo in 30 patients in premature labor. Treatment consisted of an intravenous infusion for at least 8 hours, and then of subcutaneous injections four times daily for 3 days together with peroral treatment, which was continued until the end of week 36 of pregnancy. In 12 of 15 terbutaline-treated patients (80 per cent) premature labor was arrested beyond the treatment period, compared with three of 15 in the placebo group (20 per cent). This difference is statistically significant (p less than 0.01). No serious side effects were observed. During infusion, there was an increase in maternal heart rate. This was more pronounced in the terbutaline group (30 per cent) than in the placebo group (9 per cent). There were no adverse effects on blood pressure, but fetal tachycardia was observed more frequently in the terbutaline than in the placebo group. The results suggest that terbutaline is a safe, potent, and well-tolerated inhibitor of premature labor.