Department of Obstetrics and Gynecology, Faculty of Medicine in Plzen, Charles University, Plzen, Czech Republic.
Department of Obstetrics and Gynecology, 1st Faculty of Medicine, Charles University, Prague, Czech Republic.
Ultrasound Obstet Gynecol. 2021 Aug;58(2):303-308. doi: 10.1002/uog.23629. Epub 2021 Jul 12.
The aim of this study was to explore the risk of levator ani muscle (LAM) avulsion and enlargement of the levator hiatus following vaginal birth after Cesarean section (VBAC) in comparison with vaginal delivery in primiparous women.
In this two-center observational case-control study, we identified all women who had a term VBAC for their second delivery at the Departments of Obstetrics and Gynecology at the Faculty of Medicine in Pilsen and the 1 Faculty of Medicine in Prague, Charles University, Czech Republic, between 2012 and 2016. Women with a repeat VBAC, preterm birth or stillbirth were excluded from the study. As a control group, we enrolled a cohort of primiparous women who delivered vaginally during the study period. To increase our control sample, we also invited all primiparous women who delivered vaginally in both participating units between May and June 2019 to participate. All participants were invited for a four-dimensional pelvic floor ultrasound scan to assess LAM trauma. LAM avulsion and the area of the levator hiatus were assessed offline from the stored pelvic floor volumes obtained at rest, during maximum contraction and during Valsalva maneuver. The laterality of the avulsion was also noted. The cohorts were then compared using the χ test and Wilcoxon's two-sample test according to the normality of the distribution. P < 0.05 was considered statistically significant. Multivariate regression analysis, controlling for age and body mass index (BMI), was also performed.
A total of 356 women had a VBAC for their second delivery during the study period. Of these, 152 (42.7%) attended the ultrasound examination and full data were available for statistical analysis for 141 women. The control group comprised 113 primiparous women. A significant difference was observed between the VBAC group and the control group in age (32.7 vs 30.1 years; P < 0.05), BMI (28.4 vs 27.4 kg/m ; P < 0.05) and duration of the first and second stages of labor (293.1 vs 345.9 min; P < 0.05 and 27.6 vs 35.3 min; P < 0.05, respectively) at the time of the index birth. The LAM avulsion rate was significantly higher in the VBAC compared with the control group (32.6% vs 18.6%; P = 0.01). The difference between the groups was observed predominantly in the rate of unilateral avulsion and remained significant after controlling for age and BMI (adjusted odds ratio 2.061 (95% CI, 1.103-3.852)). There was no statistically significant difference in the area of the levator hiatus at rest (12.0 vs 12.6 cm ; P = 0.28) or on maximum Valsalva maneuver (18.6 vs 18.7 cm ; P = 0.55) between the VBAC and control groups. The incidence of levator hiatal ballooning was comparable between the groups (17.7% and 18.6%; P = 0.86).
VBAC is associated with a significantly higher rate of LAM avulsion than is vaginal birth in nulliparous women. The difference was significant even after controlling for age and BMI. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.
本研究旨在探讨与初产妇阴道分娩相比，经剖宫产（VBAC）分娩的阴道分娩后阴道分娩中肛提肌（LAM）撕裂和提肛裂孔增大的风险。
在这项两中心观察性病例对照研究中，我们在捷克共和国比尔森医科大学和布拉格查理大学第一医科大学的妇产科部门确定了所有在 2012 年至 2016 年期间进行第二次 VBAC 的足月 VBAC 的妇女。排除了再次 VBAC、早产或死产的妇女。作为对照组，我们招募了一组在研究期间阴道分娩的初产妇。为了增加我们的对照样本，我们还邀请了所有 2019 年 5 月至 6 月在两个参与单位阴道分娩的初产妇参加。所有参与者都被邀请进行四维盆底超声扫描，以评估 LAM 损伤。在休息、最大收缩和瓦尔萨尔瓦动作期间，从获得的存储盆底容积中离线评估 LAM 撕裂和提肛裂孔的区域。还注意到撕裂的偏侧性。根据分布的正态性，使用 χ 检验和 Wilcoxon 两样本检验比较队列。P < 0.05 被认为具有统计学意义。还进行了控制年龄和体重指数（BMI）的多变量回归分析。
在研究期间，共有 356 名妇女进行了第二次 VBAC 分娩。其中，152 名（42.7%）参加了超声检查，141 名妇女的完整数据可用于统计分析。对照组包括 113 名初产妇。VBAC 组和对照组在年龄（32.7 岁 vs 30.1 岁；P < 0.05）、BMI（28.4 公斤/米 2 与 27.4 公斤/米 2 ；P < 0.05）和第一和第二产程持续时间（293.1 分钟与 345.9 分钟；P < 0.05 和 27.6 分钟与 35.3 分钟；P < 0.05，分别）方面存在显著差异。VBAC 组 LAM 撕裂的发生率明显高于对照组（32.6% vs 18.6%；P = 0.01）。在控制年龄和 BMI 后，两组之间的差异主要表现在单侧撕裂的发生率上，并且仍然具有统计学意义（调整后的优势比 2.061（95%CI，1.103-3.852））。VBAC 组和对照组在休息时的提肛裂孔面积（12.0 平方厘米与 12.6 平方厘米；P = 0.28）或最大瓦萨尔瓦动作时（18.6 平方厘米与 18.7 平方厘米；P = 0.55）均无统计学差异。两组之间提肛裂孔气球样扩张的发生率相当（17.7%和 18.6%；P = 0.86）。
与初产妇阴道分娩相比，VBAC 与肛提肌撕裂的发生率明显更高。即使在控制年龄和 BMI 后，差异仍然显著。© 2021 年国际妇产科超声学会。
