664: Oxytocin use during trial of labot after cesarean section (TOLAC)-is it really that dangerous?

Abstract

section (TOLAC)-is it really that dangerous? Shunit Armon, Aharon Tevet, Tehila Avitan, Hadar Rosen, Surina Grisaro-Granovsky, Arnon Samueloff Shaare Zedek Medical Center, Obstetrics and Gynecology, Jerusalem, Israel, Shaare Zedek Medical Center, Obstetrics and Gynecology, Jerusalem, Israel, Shaare Zedek MC, Affiliated to the Hebrew University Medical School, Obstetrics and Gynecology, Jerusalem, Israel OBJECTIVE: To evaluate the safety of oxytocin during TOLAC. STUDY DESIGN: Prospective historical cohort trial in a tertiary center, May 2005-May 2011. All women, with a history of a single low transverse cesarean section (LSTCS) attempting vaginal delivery were included. Multifetal gestation, noncephalic presentations, known fetal malformations and intrauterine death were excluded. A strict protocol was implemented for Oxytocin use during induction/augmentation of labor. The protocol allowed use of oxytocin at an initial dose of 0.5mU/min, with increments of 0.5mU/min at 20’ intervals. Continuous FHR monitoring was mandated. Oxytocin was withheld from grandmultiparas and women with uterine malformations. Statistical analysis:descriptive,t test, chi square, Pearson coefficient, Fishers exact test,logistic regression model. RESULTS: During the study period 73,881 deliveries were attended, 4806 met entry criteria and analyzed according to oxytocin use. Group 1-665(13.8%) women treated with oxytocin (mean duration of 267 min). Group 2-4141 (86.2%) women not treated with oxytocin. Groups were comparable for maternal age, gestational age and epidural anesthesia. The overall rate of uterine rupture (UR) was .3%, and did not differ between the groups (p .42) nor did the finding of scar dehiscence. Grandmultiparas did not have a higher UR rate (p .76). Duration of oxytocin use did not effect the rate of UR (P .09). Women in group 1 were more likely to be delivered by CS or Vaccum. The incidence of adverse outcomes mainly post partum hemorrhage (PPH) and febrile morbidity was higher in the oxytocin group, this could be explained by the higher CS rate and oxytocin use. There were no maternal deaths. Neonatal outcomes: there was no difference between the groups regarding NICU admission. Surprisingly, The incidence of 5 apgar score 7 was higher among neonates from the “no oxytocin” group, and did not change after adjustment for gestational age. One neonatal death was recorded (group 1). CONCLUSION: Use of oxytocin under a strict protocol does not pose an additional risk of uterine rupture during TOLAC.