Trial of labor after cesarean in the low-risk obstetric population: a retrospective nationwide cohort study

Objective:the purpose of this study was to evaluate the risk of adverse maternal outcomes associated with trial of labor (tol) after cesarean during subsequent pregnancies in the low-risk population.study design:we conducted a retrospective cohort study using the nationwide inpatient sample and icd-9 diagnostic and procedure codes from the years 2003 to 2011. a cohort of low-risk pregnant women with a history of previous cesarean delivery were identified and separated into two groups: tol and no tol. logistic regression analysis was used to calculate odds ratios (ors) comparing adverse maternal outcomes between these two groups.results:out of 7 290 474 registered deliveries, there were 685 137 low-risk women who met inclusion criteria. of these women, 144 066 (21.0%) underwent a tol, with rates remaining steady over the course of our study. the tol group was at increased risk of overall morbidity (or 1.74, 95% confidence interval (ci), 1.66–1.79), most notably uterine rupture (or 22.52, 95% ci, 19.35–26.20, p<0.01). a secondary analysis showed no apparent correlation between tol and concomitant adverse maternal outcomes in cases of uterine rupture.conclusion:although these outcomes remain rare, low-risk women undergoing a tol remain at increased risk of adverse maternal events as compared with those who chose elective repeat cesarean delivery.