Objective: To explore the influencing factors of the vaginal birth after cesarean section (VBAC), and establish a model for predicting the risk of trial of the trial of labor after cesarean section (TOLAC). Methods: From January 2016 to December 2018, total 694 pregnant women who underwent TOLAC in Northwest Women's and Children's Hospital were retrospectively analyzed. Those cases were divided into two groups according to the mode of delivery: the VBAC group and the failed TOLAC group. At the same time, 700 cases in the elective repeat cesarean section (ERCS) group were randomly selected as control group. The influencing factors of VBAC were analyzed by univariate and multivariate logistic regression, and the pregnancy outcomes between the three groups were compared. Results: (1) The VBAC rate was 76.1% (528/694) and 166 women underwent the failed TOLAC (23.9%, 166/694). (2) Univariate analysis found that, the pre-pregnancy body mass index (BMI) [(22.0±3.0), (23.3±2.7) kg/m(2)], the previous vaginal delivery history [10.4%(55/528), 3.6%(6/166)], the cervical score (5.2±1.9,4.3±1.6) and the neonatal birth weight [(3 315±468), (3 484±274) g] of the VBAC group were significantly different from the failed TOLAC group (P<0.05). (3) The comparison of pregnancy outcomes: the neonatal birth weight was (3 315±468) g, and the intrapartum hemorrhage volume was (255±121) ml in the VBAC group, which were significantly lower than those in the failed TOLAC group [intrapartum hemorrhage (325±173) ml] and the ERCS group [(3 572±344) g, (281±125) ml], there were statistically significant differences in the comparison among the three groups (all P<0.05). Two cases of bladder injury occurred during cesarean section in the TOLAC failure group (1.2%,2/166). The rates of the blood transfusion, puerperal infection, 5-minute Apgar score and neonatal ICU admission among the three groups were no statistically significantly different (all P>0.05). There was no maternal or perinatal death. (4) Multivariate logistic regression analysis showed that the delivery age of pregnant women (OR=0.92, 95%CI: 0.87-0.98), pre-pregnancy BMI (OR=0.92, 95%CI:0.86-0.98), vaginal delivery history (OR=3.31, 95%CI: 1.35-8.01), cervical score (OR=1.29, 95%CI: 1.13-1.42) and the birth weight of the neonates <3 300 g (OR=3.15, 95%CI: 2.02-4.90) were independent influencing factors for VBAC. The area under curve of the receiver operating characteristic curve was 0.74. Conclusions: The influencing factors of VBAC are delivery age, pre-pregnancy BMI, vaginal delivery history, cervical score and neonatal birth weight <3 300 g. The adequate individualized management and assessment of the TOLAC may be helpful to improve the VBAC rate.
目的： 探讨剖宫产术后再次妊娠阴道分娩（VBAC）的影响因素，建立适合剖宫产术后再次妊娠阴道试产（TOLAC）风险的预测模型。 方法： 回顾性分析2016年1月至2018年12月于西北妇女儿童医院分娩的TOLAC孕妇共694例，并根据最终的分娩方式分为VBAC组和TOLAC失败中转剖宫产组（TOLAC失败组），同时选取同期自愿行选择性再次剖宫产（ERCS）组700例孕妇为对照。采用单因素分析和多因素logistic回归分析VBAC的影响因素，并比较3组孕妇的妊娠结局。 结果： （1）总体VBAC率为76.1%（528/694），TOLAC失败中剖宫产的孕妇166例（23.9%，166/694）。（2）单因素分析发现，VBAC组与TOLAC失败组孕妇的妊娠前体质指数（BMI）[分别为（22.0±3.0）、（23.3±2.7）kg/m(2)]，既往自然分娩史者的比例[10.4%（55/528）、3.6%（6/166）]，入院子宫颈评分[分别为（5.2±1.9）、（4.3±1.6）分]、新生儿出生体重[分别为（3 315±468）、（3 484±274）g]分别比较，差异均有统计学意义（P均<0.05）。（3）3组孕妇的妊娠结局：VBAC组孕妇的新生儿出生体重、产时出血量[（255±121）ml]均低于TOLAC失败组[出血量为（325±173）ml]及ERCS组[（3 572±344）g、（281±125）ml]；3组间比较，差异均有统计学意义（P均<0.05）。TOLAC失败组孕妇剖宫产术中出现2例（1.2%，2/166）膀胱损伤。3组孕妇的输血、产褥感染的发生率、新生儿5分钟Apgar评分、转新生儿ICU的比例分别比较，差异均无统计学意义（P均>0.05）；无孕妇及围生儿死亡。（4）多因素logistic回归分析显示，孕妇的分娩年龄（OR=0.92，95%CI为0.87~0.98）、妊娠前BMI（OR=0.92，95%CI为0.86~0.98）、既往自然分娩史（OR=3.31，95%CI为1.35~8.01）、入院子宫颈评分（OR=1.29，95%CI为1.13~1.42）及新生儿出生体重<3 300 g（OR=3.15，95%CI为2.02~4.90）均是VBAC的独立影响因素，受试者工作特征曲线下面积为0.74。 结论： VBAC的影响因素为孕妇的分娩年龄、妊娠前BMI、既往自然分娩史、入院子宫颈评分和新生儿出生体重<3 300 g。对于剖宫产术后再次妊娠的孕妇进行充分的妊娠期个体化管理与评估，能够提高VBAC率。.
Keywords: Cesarean section, repeat; Forecasting; Pregnancy outcome; Vaginal birth after cesarean.