Analysis of factors related to the success of external cephalic version and the establishment of line chart prediction model

WU Zhi-wei; WANG Xue-zhuo; XIAO Yun-shan; ZHANG Xue-qin

doi:10.19538/j.fk2025070120

Abstract：Objective To analyse the influencing factors related to the success of external cephalic version,and to construct a line chart model and verify the predictive efficacy.Methods A retrospective cohort study was conducted which included 230 pregnant women who underwent external cephalic version at Women and Children's Hospital Affiliated to Xiamen University from April 2018 to October 2022,of which 165 cases were successful and 65 failed.The cases were divided into training set and validation set according to the ratio of 7∶3.The clinical data and preoperative ultrasound indexes of the study subjects were collected,and the influencing factors of the success of external cephalic version were analysed by logistic regression.The line chart model was then established by R 4.2.3 software.The C-index and standard calibration curve were used to assess the efficacy of the model,and the decision curve was used to assess the clinical practicality of the model.Results Logistic regression analysis showed that frank breech,anterior placenta,amniotic fluid index＜14.10 cm,and primiparity were the risk factors for the success of external cephalic version[odds ratio(OR)values being 0.173,0.170,1.335,and 1.975,P＜0.05].A line chart model was constructed based on the above influencing factors.The C-index of the training set was 0.838(95％CI 0.775-0.900),and the area under the ROC curve was 0.815;the C-index of the validation set was 0.822(95％CI 0.759-0.884)and the area under the ROC curve was 0.780.The model curves were closer to the ideal curves,and separated from the extreme curves.Conclusion The line chart prediction model based on placental position,breech presentation type,amniotic fluid index,and the number of deliveries has high efficacy and good clinical practicality,and it can be used as a tool for screening and assessing the population fit for external cephalic version.