Development of a Modified Score System as Prediction Model for Successful Vaginal Birth After Cesarean Delivery

This study was designed to establish a modified prediction score system to improve the safety and success rate of vaginal birth after cesarean delivery (VBAC). We recruited 406 patients (between January 2012 and December 2016) and generated a modified score system in predicting the success rate of VBAC. All patients were required to sign informed consent forms. There were 87.2% of patients who had successful VBAC deliveries and 12.8% patients who had repeated cesarean sections. We conducted multivariable logistic regression and found seven variables that were associated with VBAC success, including previous primary indication of cesarean delivery (odds ratio (OR), 2.1; 95% confidence interval (CI), 1.4-3.0), previous vaginal birth history (OR, 2.5; 95% CI, 1.8-3.8), < 40 years of age (OR, 2.1; 95% CI, 1.2-3.3), < 20 kg weight gain (OR, 1.5; 95% CI, 1.2-2.3), no labor induction (OR, 1.9; 95% CI, 1.5-2.9), high score of pelvic/birth weight (OR, 1.4; 95% CI, 1.1-2.1), and Bishop score (OR, 1.3; 95% CI, 1.2-1.4). After adjustment for optimism, the area under the receiver operating characteristic curve (AUC-ROC) was 0.849 (95% CI, 0.78-0.89), and the modified VBAC score was positively correlated with the success rate of trial of labor after cesarean delivery (TOLAC). A valid and useful score system was established to predict VBAC success rate.