Thirty-two patients were evaluated to determine the effects of meperidine and promethazine administered during active labor, with con-tinous electronic monitoring of multiple fetal and maternal cardiovascular parameters and uterine activity. Meperidine produced no apparent significant fetal or maternal cardiovascular changes. In contrast maternal tachycardia occurred in all patients receiving promethazine. There were minimal heart rate level changes noticed in the fetus but a striking change in the beat-to-beat variation was encountered. A quantitative on-line method was used to measure uterine activity, which was found to increase in all patients but one.
© 1973 The American College of Obstetricians and Gynecologists