Model Performance
Nomograms derived from the multivariable model to predict the probability of cesarean delivery were shown in Figure 1. The sum of the assigned points for each variable in the nomograms predicted the overall risk. The discrimination of this prediction model was evaluated using the AUC (0.85, 95% CI: 0.79-0.91;P < 0.001) (Figure 2a). The calibration plots showed good agreement between prediction and observation with a calibration slope of 1.01 (Figure 2b). Additionally, the Hosmer-Lemeshow test yielded a nonsignificant statistic (P = 0.472), which indicated a reasonable model fit.