Abstract:

Objective　To construct a risk prediction model for early pelvic organ prolapse (POP) in primiparas undergoing vaginal delivery based on pelvic floor ultrasound parameters and clinical data. Methods　The clinical data of 129 primiparas who underwent vaginal delivery in Xianyang First People's Hospital from February 2021 to August 2024 were retrospectively analyzed. They were (28.11±3.77) years old and (38.41±1.82) weeks pregnant when they delivered. All the primiparas underwent three-dimensional ultrasound examination on the pelvic floor. According to the occurrence of early POP, they were divided into a prolapse group (32 cases) and a non-prolapse group (97 cases). The pelvic floor ultrasound parameters and clinical data were compared between the two groups. The influencing factors of early POP in the primiparas were analyzed by the multivariate logistic regression analysis. A nomogram model was drawn by the R3.4.3 software package, and the nomogram model was verified by the Bootstrap method. The calibration curve and receiver operating characteristic curve (ROC) were drawn to evaluate the calibration and prediction efficiency of the nomogram model. The independent sample t and χ² tests were used as the statistical methods. Results　The posterior vesicourethral angle, anteroposterior diameter of levator hiatus, and area of levator hiatus under Valsalva maneuver in the prolapse group were higher than those in the non-prolapse group (all P<0.05). The proportions of the women with gestational age > 37 weeks at delivery, perineal tear, lateral episiotomy, and neonatal birth weight > 4 kg in the prolapse group were higher than those in the non-prolapse group (all P<0.05). The multivariate logistic regression analysis results showed that the high posterior vesicourethral angle, anteroposterior diameter of levator hiatus, and area of levator hiatus, gestational age > 37 weeks at delivery, perineal tear, lateral episiotomy, and neonatal birth weight > 4 kg were all risk factors for early POP in the primiparas undergoing vaginal delivery (all P<0.05). The consistency index (C-index) of the nomogram model constructed based on the above factors verified by the Bootstrap method was 0.860, and the calibration curve was in good agreement with the ideal curve. The ROC results showed that the area under the curve (AUC), sensitivity, and specificity of this model for predicting early POP in the primiparas were 0.890, 90.62%, and 85.57%, respectively. Conclusions　Pelvic floor ultrasound parameters, such as posterior vesicourethral angle, anteroposterior diameter of levator hiatus, and area of levator hiatus, gestational age > 37 weeks at delivery, perineal tear, lateral episiotomy, and neonatal birth weight > 4 kg are all risk factors for early POP in primiparas undergoing vaginal delivery. The risk prediction model constructed based on these factors has good clinical application value.

Key words:

Vaginal delivery, Primiparas, Pelvic floor ultrasound, Early pelvic organ prolapse, Prediction model

摘要：

目的　基于盆底超声参数和临床资料构建经阴道分娩初产妇早期盆腔脏器脱垂（POP）的风险预测模型。方法　采用回顾性分析，选取2021年2月至2024年8月咸阳市第一人民医院收治的129例经阴道分娩初产妇，年龄（28.11±3.77）岁，分娩孕周（38.41±1.82）周，均行盆底三维超声检查。根据产妇是否发生早期POP将其分为脱垂组（32例）和未脱垂组（97例）。比较两组盆底超声参数和临床资料，并应用多因素logistic回归分析法分析经阴道分娩初产妇早期POP的影响因素，另通过R3.4.3软件包绘制列线图模型，依托Bootstrap法对列线图模型进行验证，并绘制校准曲线、受试者工作特征曲线（ROC）评价列线图模型的校准度、预测效能。统计学方法采用独立样本t检验、χ²检验。结果　脱垂组Valsalva动作下膀胱尿道后角、肛提肌裂孔前后径、肛提肌裂孔面积及分娩孕周>37周、会阴撕裂、会阴侧切、新生儿出生体重>4 kg占比均高于未脱垂组（均P<0.05）；多因素logistic回归分析结果显示，膀胱尿道后角、肛提肌裂孔前后径、肛提肌裂孔面积较高以及分娩孕周>37周、会阴撕裂、会阴侧切、新生儿体重>4 kg均是经阴道分娩初产妇早期POP的危险因素（均P<0.05）；根据上述影响因素构建的列线图模型经Bootstrap法验证的一致性指数（C-index）为0.860，校准曲线与理想曲线拟合度良好；ROC结果显示，模型预测阴道分娩初产妇早期POP的曲线下面积（AUC）、灵敏度、特异度分别为0.890、90.62%、85.57%。结论　盆底超声参数膀胱尿道后角、肛提肌裂孔前后径、肛提肌裂孔面积以及分娩孕周>37周、会阴撕裂、会阴侧切、新生儿体重>4 kg均是经阴道分娩初产妇早期发生POP的危险因素，据此构建的风险预测模型临床应用价值良好。

关键词:

阴道分娩, 初产妇, 盆底超声, 早期盆腔脏器脱垂, 预测模型