Incidence of Uterine Tachysystole in Women Induced with Oxytocin

Abstract

To determine the incidence of uterine tachysystole (UT) using nomenclature defined by the American College of Obstetricians and Gynecologists (ACOG) and Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN). Cohort study using retrospective chart reviews and concomitant independent analyses of fetal monitor strips. A 10-bed labor and delivery unit in a community hospital with an average of 400 deliveries monthly. Of 346 total deliveries in October 2009, 55 patients qualified for this study. Inclusion criteria were women with a singleton, viable fetus in vertex presentation and who received oxytocin infusion for induction of labor. We analyzed 798.5 hours of fetal monitor strips in 30-minute increments according to each of four UT criteria. We collected data on the dose of oxytocin, the National Institute of Child Health and Human Development (NICHD) fetal heart rate categories, maternal age, parity, pregnancy risk factors, indication for induction, mode of delivery, birth weight, and Apgar scores. We identified 661 incidences of UT out of 1,597 increments with an overall UT rate of 41%. Fifty-four of 55 patients (98%) demonstrated one or more occurrences of UT. Interrater reliability achieved an 86.3% correlation (718 vs. 698 occurrences). Results of this study highlight the need for careful titration of oxytocin and prompt management of UT. This increased awareness can enhance the health, safety, and well-being of pregnant women and their fetuses.