Varvoutis Megan S, Sayres Lauren C, Dotters-Katz Sarah K
Division of Maternal Fetal Medicine, Department of OBGYN, Duke University, Durham, North Carolina.
AJP Rep. 2020 Jan;10(1):e37-e41. doi: 10.1055/s-0040-1702924. Epub 2020 Mar 4.
The study aims to reduce cesarean rates, eligible women are being offered an option of vaginal birth after cesarean (VBAC). However, little data exist regarding efficacy of amniotomy as a tool in this population. We sought to evaluate the impact of early amniotomy on VBAC success. This is a secondary analysis case-control study using the MFMU (Maternal-Fetal Medicine Units Network) Cesarean Registry. Women were included if they had a singleton pregnancy, were attempting VBAC, and underwent induction with artificial rupture of membranes. Cases were defined as subjects with successful VBAC; controls were defined as subjects with failed trial of labor after cesarean (TOLAC). Early amniotomy was defined as amniotomy at <4 cm. Demographic and obstetric characteristics were compared and multivariate logistic regression was performed. A total of 1,490 women were included. Early amniotomy occurred in 59.5% with VBAC versus 63.2% with failed TOLAC ( = 0.24). After controlling for body mass index, prior vaginal delivery, African-American race, labor length, gestational age, birthweight, epidural use, Foley catheter balloon ripening, induction method and oxytocin use, early amniotomy was associated with a 34% decrease in VBAC success ( < 0.01). Women who had early amniotomy did not have higher rates of chorioamnionitis (2.8 vs. 2.9%, > 0.99). Unlike data from nulliparous women, our data suggest that induction with early amniotomy does not increase the likelihood of VBAC.
该研究旨在降低剖宫产率，为符合条件的女性提供剖宫产术后阴道分娩（VBAC）的选择。然而，关于羊膜穿刺术在这一人群中的有效性的数据很少。我们试图评估早期羊膜穿刺术对VBAC成功率的影响。 这是一项使用母胎医学单位网络（MFMU）剖宫产登记处进行的二次分析病例对照研究。纳入的女性需为单胎妊娠、尝试VBAC并接受人工破膜引产。病例定义为VBAC成功的受试者；对照定义为剖宫产术后引产失败（TOLAC）的受试者。早期羊膜穿刺术定义为在宫颈扩张<4厘米时进行的羊膜穿刺术。比较了人口统计学和产科特征，并进行了多因素逻辑回归分析。 总共纳入了1490名女性。VBAC组中59.5%的女性进行了早期羊膜穿刺术，而TOLAC失败组中这一比例为63.2%（P = 0.24）。在控制了体重指数、既往阴道分娩史、非裔美国人种族、产程、孕周、出生体重、硬膜外麻醉使用、Foley导管球囊促宫颈成熟、引产方法和缩宫素使用等因素后，早期羊膜穿刺术与VBAC成功率降低34%相关（P<0.01）。进行早期羊膜穿刺术的女性绒毛膜羊膜炎发生率并未更高（2.8%对2.9%，P>0.99）。 与初产妇的数据不同，我们的数据表明早期羊膜穿刺术引产并不会增加VBAC的可能性。
