Amniutic pressure and maternal heart rate were recorded continuously and simultaneously in 15 women in labor or prelabor. Orciprenaline (Alupent) was administered through an intravenous infusion pump at the rate of 10 and 20 μg/min. Uterine contractility and maternal and fetal heart rate were measured before its onset and during the infusion. The development and stabilization of the effects were studied. Continuous intravenous infusions of orciprenaline at rates of 10 and 20 μg/min are recommended. They proved to be very useful in obtaining uterine inhibition with a minimum of undesirable side effects.