Factors affecting success of trial of labor after cesarean delivery

Abstract

Objective To explore the influencing factors affecting the success of trial of labor after cesarean (TOLAC). Methods Delivery outcomes of 435 pregnant women after cesarean section who had TOLAC in Nanfang Hospital of Southern Medical University between January 2009 and December 2013 were retrospectively analyzed. All of the recruited women were term singleton pregnant with cephalic presentation, spontaneous labor, history of single cesarean section (CS), but without medical problems or contraindications of vaginal delivery, and they were willing to have a trial of labor. Factors including maternal body mass index (BMI), age, interval between this delivery and last cesarean delivery, cervix dilation and effacement on admission, history of vaginal delivery, presentation of previous cesarean delivery indication, and neonatal birth weight were analyzed by bivariate analysis and multivariable logistic regression. Results Among the 435 gravidas, 315(72.4%) succeeded in vaginal birth after cesarean (VBAC), whereas 120 failed. Compared with the corresponding controls, those women whose BMI at admission 2 years [74.6% (256/343) vs 64.1% (59/92)] , cervix dilation >3 cm at admission [94.1% (80/85) vs 67.1%(235/350)], cervical effacement >50% at admission [82.8% (198/239) vs 59.7%(117/196)], and those who had history of vaginal birth [90.4% (103/114) vs 66.0% (212/321)], repeated indications of previous CS [74.2% (284/383) vs 59.6% (31/52)], gave birth to a baby less than 3 500 g [75.3%(223/296) vs 66.2%(92/139)] showed significantly higher VBAC successful rate [adjusted OR (95%CI): 1.982(1.220-3.221), 1.644(1.008-2.688), 7.830(3.087-19.875), 3.261( 2.098-5.069), 4.814(2.480-9.345), 1.943(1.067-3.538), 1.561(1.005-2.422), all P 0.05]. Multivariable logistic regression analysis showed that higher VBAC success rate was affected by vaginal delivery history [adjusted OR(95%CI): 2.927(1.553-5.517)], cervix dilation >3 cm on admission [4.146(1.549-11.100)], cervix effacement >50% on admission [2.306(1.415-3.756)]. Conclusions The main factors affecting the success of TOLAC are vaginal delivery history, cervix dilation and effacement on admission. Key words: Vaginal birth after cesarean; Delivery, obstetric; Prognosis