Objective To explore the diagnostic value of cardiometabolic index and early bladder neck mobility for postpartum pelvic floor dysfunction (PFD).Methods A total of 317 parturients who visited our hospital within 6~8 weeks after delivery from January 2022 to December 2024 were selected as the research subjects. These parturients were divided into the PFD group (n = 170) and the non-PFD group (n = 147) based on the occurrence of PFD. All parturients underwent transperineal pelvic floor ultrasound scan and their clinical data were collected. The logistic regression model was used to analyze the influencing factors of PFD, and the receiver operating characteristic (ROC) curve was used to analyze the diagnostic efficacy of cardiometabolic index and early bladder neck mobility for PFD in parturients. A risk assessment nomogram model was established, and its performance was internally and externally validated using the Hosmer-Lemeshow (H-L) goodness-of-fit test, calibration curves, ROC curves, and decision curve analysis (DCA). Explainability analysis was performed using SHapley Additive exPlanations (SHAP).Results Comparisons of height, systolic blood pressure, diastolic blood pressure, gestational age at delivery, neonatal birth weight, instrumental vaginal delivery, and levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) between the two groups revealed no statistically significant differences (all P > 0.05). The PFD group had significantly older age, higher body mass index (BMI), waist-to-height ratio, and cardiometabolic index, greater bladder neck mobility, and longer duration of the second stage of labor than the non-PFD group (P < 0.05). Multivariable logistic regression analysis showed that older age [O^R = 1.873 (95% CI: 1.531, 2.291) ], higher BMI [O^R = 1.530 (95% CI: 1.291, 1.814)], longer duration of the second stage of labor [O^R = 1.022 (95% CI: 1.010, 1.034) ], higher cardiometabolic index [O^R = 2.355 (95% CI: 1.710, 3.242) ], and greater bladder neck mobility [O^R = 1.547 (95% CI: 1.340, 1.785) ] were risk factors for PFD (all P < 0.05). ROC curve analysis showed that the cardiometabolic index had the highest specificity for diagnosing PFD, with a specificity of 82.3% (95% CI: 0.752, 0.881), whereas bladder neck mobility showed the highest sensitivity for predicting PFD, with a sensitivity of 88.2% (95% CI: 0.824, 0.927). The combined assessment of cardiometabolic index and bladder neck mobility achieved the highest predictive performance for PFD, with an AUC of 0.899 and relatively high sensitivity and specificity. The risk assessment nomogram demonstrated good discrimination in the training dataset, with a concordance index of 0.837 (95% CI: 0.795, 0.879). Internal validation indicated satisfactory model calibration (P > 0.10). Calibration curves generated using bootstrap resampling showed good agreement between the predicted and observed probabilities (P > 0.10). The ROC curve yielded an AUC of 0.76 (95% CI: 0.67, 0.86), indicating moderate-to-good discriminative ability. DCA demonstrated a positive net benefit across all threshold probabilities, suggesting that the use of the model to evaluate the risk of PFD provided greater clinical net benefit than the "treat-all" and "treat-none" strategies in the training dataset. External validation showed satisfactory model calibration (P > 0.10). Bootstrap-derived calibration curves showed good agreement between predicted and observed probabilities (P > 0.10). The ROC curve yielded an AUC of 0.78 (95% CI: 0.65, 0.91), indicating moderate-to-good discriminative ability. DCA demonstrated positive net benefit across all threshold probabilities, suggesting that the model provided greater clinical net benefit than the “treat-all” and “treat-none” strategies in the validation dataset. The SHAP importance plot showed that the variables ranked by their contribution to PFD prediction were bladder neck mobility, age, cardiometabolic index, duration of the second stage of labor, and BMI. According to the model, higher SHAP values for these features were associated with a higher likelihood of developing PFD.Conclusion Age, BMI, duration of the second stage of labor, cardiometabolic index, and bladder neck mobility are identified as influencing factors for postpartum PFD. The combined assessment of cardiometabolic index and bladder neck mobility demonstrates high predictive value for postpartum PFD.