Prediction of vaginal birth after cesarean delivery in Chinese parturients.

There is an urgent need in China to better predict vaginal birth after cesarean (VBAC) to face the challenge of the second child policy. We aimed to validate a widely used VBAC prediction model (Grobman's model) and a modified version of this model in a Chinese population. In this retrospective cohort study, 444 women with one cesarean delivery and at least one subsequent attempt for a trial of labor in Nanjing, China were included. The considered potential VBAC predictors included Grobman's background variables and five new variables. Overall, a total of 370 women had VBAC, with a success rate of 83.3%. The new background variables "maternal height" and "estimated fetal weight" were considered as two additional predictors for VBAC. The AUC of Grobman's model was 0.831 (95%CI = 0.775-0.886) while the AUC of our modified model with two new variables added was 0.857 (sensitivity = 72.2%, specificity = 83.8%). However, the difference between the AUC of the two models was not significant (Z = -1.69, P = 0.091). We confirmed that Grobman's model was accepted in the Chinese population. A modified model that is supplemented with maternal height and estimated fetal weight needs to be further studied in the Chinese population.