Uterine rupture during induced or augmented labor in gravid women with oneprior cesarean delivery

OBJECTIVE: Our purpose was to examine the risk of uterine rupture during in duction or augmentation of labor in gravid women with 1 prior cesarean deli very. STUDY DESIGN: The medical records of all gravid women with history of cesar ean delivery who attempted a trial of labor during a 12-year period at a si ngle center were reviewed. The current analysis was limited to women at ter m with 1 prior cesarean delivery and no other deliveries. The rate of uteri ne rupture in gravid women within that group undergoing induction was compa red with that in spontaneously laboring women. The association of oxytocin induction, oxytocin augmentation, and use of prostaglandin Ee gel with uter ine rupture was determined. Logistic regression analysis was used to examin e these associations, with control for confounding factors. RESULTS: Of 2774 women in the analysis, 2214 had spontaneous onset of labor and 560 women had labor induced with oxytocin or prostaglandin Ep gel. The overall rate of rupture among all patients With induction of labor was 2.3 %, in comparison with 0.7% among women with spontaneous labor (P = .001). A mong 1072 patients receiving oxytocin augmentation, the rate of uterine rup ture was 1.0%, in comparison with 0.4% in nonaugmented, spontaneously labor ing patients (P=.1). In a logistic regression model with control for birth weight, use of epidural, duration of labor, maternal age, year of delivery, and years since last birth, induction with oxytocin was associated with a 4.6-fold increased risk of uterine rupture compared with no oxytocin use (9 5% confidence interval, 1.5-14.1). In that model, augmentation with oxytoci n was associated with an odds ratio of 2.3 (95% confidence interval, 0.8-7. 0), and use of prostaglandin E-2 gel was associated with an odds ratio of 3 .2 (95% confidence interval, 0.9-10.9). These differences were not statisti cally significant. CONCLUSION: Induction of labor with oxytocin is associated with an increase d rate of uterine rupture in gravid women with 1 prior uterine scar in comp arison with the rate in spontaneously laboring women. Although the rate of uterine rupture was not statistically increased during oxytocin augmentatio n, use of oxytocin in such cases should proceed with caution.