ABSTRACT
Objective:To analyze the factors influencing the success rate of external cephalic version (ECV) and to create a preoperative scoring scale for stratified management of pregnant women who were preparing for ECV.Methods:This prospective study was conducted on singleton pregnant women who underwent ECV without anesthesia in Fujian Maternity and Child Health Hospital from January 1, 2017, to December 31, 2019. Univariate (two independent samples t-test, Mann-Whitney U test, and Chi-square test) and multivariate logistic regression were used to screen the clinical characteristics affecting the success of ECV, and receiver operating characteristic (ROC) curve was used to determine the cut-off value and convert quantitative variables into dichotomous variables. The independent variables were scored according to the regression coefficient in multivariate logistic regression analysis, and then a preoperative scoring scale was created. The ROC curve was used to calculate the cut-off value for the scoring scale. The subjects were divided into low and high score groups according to the cut-off value. The area under the ROC curve was used for evaluating the effectiveness of the scale in predicting the success of ECV. The success rate of ECV, difficulty of the operation and mode of delivery were compared between the two groups. Results:A total of 1 338 pregnant women met the inclusion criteria during the study period. After the exclusion of 885 women, 165 refused ECV in favor of direct cesarean section, 27 spontaneously converted to cephalic position before ECV, 261 who voluntarily accepted ECV were finally enrolled. ECV succeeded in 202 cases and failed in 59. (1) Favorable factors for ECV without anesthesia were the distance between the fetal breech and ischial spine <－3.5 cm ( OR=0.177, 95% CI: 0.071-0.438, P=0.009), the sum of the fundal height and the station of the fetal breech based on the ischial spine <30.25 cm ( OR=0.225, 95% CI: 0.094-0.537, P=0.001), amniotic fluid index ≥12 cm ( OR=0.399, 95% CI: 0.164-0.969, P=0.042), the surgeon's ability to hold the fetal head or breech with one hand ( OR=0.241, 95% CI: 0.098-0.589, P=0.002; OR=0.219, 95% CI: 0.087-0.546, P=0.001), and the fetal head located on the right or left upper abdomen of the mother ( OR=0.184, 95% CI: 0.059-0.568, P=0.003; OR=0.253, 95% CI: 0.084-0.760, P=0.014). (2) The area under the ROC curve of the preoperative score for predicting the success of ECV was 0.881 (95% CI: 0.821-0.941) and the cut-off value was 5.5. The subjects were divided into low (0-5 scores) and high (6-11 scores) score groups and the area under the ROC curve for predicting the success of ECV by grouping was 0.843 (95% CI: 0.774-0.912). Compared with the low score group, the high score group had a shorter ECV duration [2.0 min (0.5-10.0 min) vs 10.0 min (0.9-25.8 min), Z=－6.83, P<0.001], less attempts [1.0 times (1.0-4.0 times) vs 3.0 times (1.0-5.0 times), Z=－8.41, P<0.001], higher success rate [92.7% (190/205) vs 21.4% (12/56), χ2=127.64, P<0.001], higher rate of vaginal birth [75.4% (147/195) vs 18.5% (10/54)] and lower cesarean section rate [24.6% (48/195) vs 81.5% (44/54)] ( χ2=58.70, P<0.001). Conclusions:Preoperative scoring based on the factors influencing the success rate of ECV (the distance between the fetal breech and ischial spine, the sum of the fundal height and the station of the fetal breech based on the ischial spine <30.25 cm, amniotic fluid index ≥12 cm, the surgeon's ability to hold the fetal head or breech with one hand, and the fetal head locating on the right or left upper abdomen of the mother) is conducive to the individualized evaluation of the difficulty and the success rate of ECV as well as the success rate of vaginal delivery after ECV, which can provide a reference for clinical stratified management of ECV patients.