剖宫产后阴道分娩的影响因素和妊娠结局分析

目的：评估剖宫产后阴道分娩（VBAC）的影响因素及其妊娠结局。方法：回顾性研究2015年1月-2016年12月在本院分娩的孕妇210例。所有孕妇均有1次剖宫产史，足月单胎，头位，无妊娠合并症和并发症，意愿阴道试产（TOLAC）。根据最终分娩方式分为TOLAC成功组（VBAC组）和TOLAC失败组。采用单因素分析和多因素Logistic回归分析剖宫产后再次阴道分娩的影响因素，并比较2组的妊娠结局。结果：TOLAC成功率为80.5%（169/210），41例因产时胎心异常或产程停滞中转剖宫产终止妊娠。多因素Logistic回归分析发现，阴道分娩史（OR=9.61，95%CI：1.20～76.96）、自然临产（OR=5.88，95%CI：2.36～14.64）及体质量指数（BMI，OR=0.86，95%CI：0.76～0.97）是剖宫产后再次阴道分娩的影响因素，其中阴道分娩和自然临产是有利因素，高BMI是不利因素，受试者工作特征（ROC）曲线下面积（AUC）为0.76。2组妊娠结局比较，TOLAC成功组出血量和输血率低于TOLAC失败组（P＜0.05），新生儿窒息率和新生儿入新生儿监护室（NICU）率差异无统计学意义（P＞0.05）。 2组均未发生子宫切除和母儿死亡等严重并发症。结论：VBAC的影响因素为阴道分娩史、自然临产和BMI，对于前次剖宫产后再次妊娠的孕妇进行充分个体化评估，进一步构建VBAC预测模型，提高TOLAC成功率。

The Outcomes of Vaginal Birth after Prior Cesarean and Related Factors

Objective:To assess the maternal and infant outcomes of vaginal birth after cesarean(VBAC),and to identify those influencing factors.Methods:A total of 210 pregnant women who underwent VBA,C in our hospital from January 2015 to December 2016 were retrospectively analyzed.All of them had a singleton pregnancy with cephalic presentation,term birth and trial of labor after casarean (TOLAC),without any pregnancy complication.Those cases were divided into two groups according to the mode of delivery:the successful TOLAC group (VBAC group) and the failed TOLAC group.The maternal-infant outcomes and other clinical data were compared.Results:The total success rate of TOLAC was 80.5％ (169/210).Forty one women underwent the failed TOLAC,due to fetal distress or a non-progress of labor.The independent influencing factors of VBAC were as follows:a prior vaginal birth (OR=9.61,95％CI:1.20-76.96),spontaneous labor(OR=5.88,95％CI:2.36-14.64) and body mass index (BMI,OR=0.86,95％CI:0.76-0.97),in which a prior vaginal birth and spontaneous labor were the protective factors and high BMI was the risk factors of VBAC.The area under curve (AUC) of the graphic receive operator characteristic (ROC) curve was 0.76.The intrapartum blood loss and the proportion who required of blood transfusion in the VBAC group were significantly lower than those in the failed TOLAC group (P＜0.05).There were no significant differences in the incidence of neonates asphyxia and proportion of neonates who had to be admitted to intensive care unit between the two groups (P＞0.05).Conclusions:The independent influencing factors of VBAC were the prior vaginal birth,spontaneous labor and BMI.The individualized assessment of VBAC,and the prediction model based on the influencing factors in future,may be helpful to improve the success rate of TOLAC.