剖宫产后阴道试产的产程特点和影响因素分析

目的 探讨剖宫产后阴道试产（trail of labor after cesarean，TOLAC）的产程特点，为临床安全管理其产程提供依据。方法 回顾性分析2016年1月至2018年12月自然临产的246例足月TOLAC孕妇，以及同时期340例自然临产、阴道分娩足月初产妇（SVB组）的临床资料。研究TOLAC的产程特点，以及前次剖宫产时机、既往阴道分娩史、妊娠间隔（1.5~3年、>3年）等对TOLAC产程的影响。结果 自然临产的足月TOLAC成功率90.2%。伴有阴道分娩史的自然临产的足月TOLAC产妇的第一、第二、总产程时间较无阴道分娩史的自然临产的足月TOLAC（wTOLAC）缩短（P<0.05）。前次妊娠临产前和临产后行剖宫产的两组，以及妊娠间隔处于1.5~3年和>3年的两组的第一、第二、总产程时间均无明显差异。wTOLAC组与SVB组比较，两组的产前体质指数、分娩孕周、产程中干预措施、产后出血量、产后出血率、输血治疗率、妊娠合并症发生率、新生儿1 min Apgar评分、产钳助产率均无明显差异。wTOLAC组的年龄、孕前体质指数、新生儿体重较SVB组大（P<0.05），分娩镇痛率较低（P<0.000 1）。应用协方差分析校正上述4个指标的组间差异：两组的产程进展模式类似，第一、总产程时限无明显差异，但第一产程宫口扩张2 cm后，尤其是宫口扩张6 cm后，wTOLAC组产程进展较快（P<0.01）；wTOLAC组的第二产程短于SVB组（P<0.001），wTOLAC组内行分娩镇痛的第二产程亦短于SVB组内行分娩镇痛的（P<0.001）；wTOLAC组内行分娩镇痛的第二产程和总产程长于未行分娩镇痛者（P<0.05）。结论 自然临产的足月TOLAC的产程模式与初产妇类似，宫口扩张6 cm后产程进展较快，且整个产程进展较初产妇稍快，分娩镇痛会延长产程。前次剖宫产时机和妊娠间隔对自然临产的足月TOLAC产程的影响较小，既往阴道分娩史是促进TOLAC产程进展的有利因素。

Labor patterns and the influence factors in women undergoing trail of labor after cesarean

Objective To investigate the labor patterns of trail of labor after cesarean (TOLAC),and to provide the basis for clinical safety management of labor process in TOLAC. Methods Two hundred and forty-six term women undergoing TOLAC and 340 term primiparae with spontaneous onset of vaginal delivery (SVB group),who underwent antenatal care and delivered from Jan 1,2016 to Dec 31,2018,were enrolled in this retrospective study.The labor patterns of TOLAC with spontaneous onset of labor were observed,as well as the influence of the timing of prior cesarean section,prior vaginal delivery history,and interpregnancy interval (1.5~3 years,>3 years) on the labor process in TOLAC. Results The success rate of term TOLAC with spontaneous onset of labor was 90.2%.Compared to term TOLAC with spontaneous onset of labor and no prior vaginal deliveries (wTOLAC),the first stage,the second stage and total labor durations of term TOLAC with spontaneous onset of labor and prior vaginal deliveries were shorter (P<0.05).There was no differences in the first stage,the second stage and total labor durations between TOLAC with prior pre-labor cesarean delivery and the ones with prior cesarean delivery in labor,so as the same indexes between the two groups with different interpregnancy intervals (1.5-3 years,>3 years).The admission body mass index,gestational age at delivery,interventions during labor,estimated blood loss,postpartum hemorrhage ratio,infusion therapy ratio,pregnant complication ratio,Apgar score at 1 minute,forceps ratio in wTOLAC group were comparable to those in SVB group.The age,pre-pregnancy body mass index and neonatal birth weight in wTOLAC group were much more than those in SVB group (P<0.05).The epidural anesthesia ratio of wTOLAC group was lower than that of SVB group (P<0.000 1).According to analysis of covariance,adjusted for the four previous different indexes, the labor patterns of the two groups were similar,and there was no difference in the first stage and total labor durations between the two groups.However,the labor process after 2 cm dilatation in the first stage of labor,especially after 6 cm dilatation in wTOLAC group,was faster than that in SVB group (P<0.01).The second stage of labor in wTOLAC group was shorter than that in SVB group (P<0.001).In the subgroup of women with epidural anesthesia,the second stage of labor in wTOLAC group was also shorter than that in SVB group (P<0.001).In wTOLAC group,the second stage and total labor durations of the women with epidural anesthesia were longer than those without epidural anesthesia (P<0.05). Conclusion The labor pattern of term TOLAC with spontaneous onset of labor was similar to nulliparous labor with faster labor process after 6 cm dilatation.However,compared to nulliparous labor,the labor process was a bit faster in TOLAC.The timing of prior cesarean section and interpregnancy interval had little effect on labor durations in TOLAC.The prior vaginal delivery was a favorable factor to improve labor process in TOLAC,while epidural anesthesia delayed the labor process in TOLAC.