Effect of diazepam on uterine activity during labor.

The effect of diazepam on uterine activity was assessed in a series of 30 patients in established spontaneous labor. The action of diazepam on the frequency and amplitude of contractions, uterine tone and fetal heart rate was monitored internally. An i.v. dose of 10 mg diazepam significantly decreased uterine activity by its direct effect on contraction frequency. No effect on uterine tone was seen. This effect of diazepam on contraction frequency was additional to its tranquilizing and muscle relaxant action.