Knight J C, Tenbrink E, Sheng J, Patil A S
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, IN, USA.
Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
J Perinatol. 2017 Apr;37(4):375-379. doi: 10.1038/jp.2016.241. Epub 2017 Jan 5.
To compare the anterior uterocervical angle and cervical length as predictors of spontaneous preterm delivery in patients with transvaginal cerclage.
We retrospectively evaluated a cohort of 142 pregnant women with transvaginal cerclage placed over a 5-year period (2010 to 2015) were evaluated. Cervical morphology characteristics were measured from endovaginal imaging, including cervical length, cerclage height, funnel volume and anterior uterocervical angle prior to cerclage placement (UCA 1), shortly after cerclage placement (UCA 2) and the last image prior to delivery (UCA 3). Cerclage failure was defined as delivery prior to 36 weeks. Univariate analysis, receiver operator characteristic curves and binary logistic regression were used for statistical analysis. Statistical significance was defined as a P<0.05.
Among the 142 women with a transvaginal cerclage, 38% had cerclage failure. The mean gestational age at birth was 29.3±5.2 weeks in the failure group compared with 37.9±2.8 weeks in those that did not fail (P<0.001). Univariate analysis identified cervical length (P=0.034) and UCA 3 (P<0.001) as significantly associated with gestational age at birth. Receiver operator characteristic curves demonstrated improved prediction of delivery prior to 34 weeks at UCA 3=108 (97% sensitivity, 65% specificity) compared to a cervical length of 25 mm. At <28 weeks, optimal performance of UCA 3 was found at 112 (100% sensitivity, 62% specificity) compared with cervical length of 25 mm (29% sensitivity, 39% specificity). Binary logistic regression revealed UCA 3>108 conferred an OR 35.1 (95% CI 7.7 to 160.3) for delivery prior to 34 weeks, and UCA 3>112 an OR 42.0 (95% CI 5.3 to 332.1) for delivery prior to 28 weeks. In comparison, CL<25 mm had an OR 4.7 (95% CI 1.8 to 12.2) for delivery prior to 34 weeks and OR 6.0 (95% CI 1.9 to 19.3) prior to 28 weeks.
In patients with transvaginal cerclage, an increasingly obtuse anterior uterocervical angle reflects an increased risk of cerclage failure in the mid-trimester. Utilization of UCA measurement as a surveillance tool may improve identification of patients at risk for cerclage failure.
比较子宫颈前角和宫颈长度作为经阴道宫颈环扎术患者自发性早产预测指标的价值。
我们回顾性评估了一组在5年期间（2010年至2015年）接受经阴道宫颈环扎术的142例孕妇。通过阴道内成像测量宫颈形态特征，包括宫颈长度、环扎高度、漏斗容积以及环扎术前（UCA 1）、环扎术后不久（UCA 2）和分娩前最后一次图像（UCA 3）时的子宫颈前角。环扎失败定义为在36周前分娩。采用单因素分析、受试者工作特征曲线和二元逻辑回归进行统计分析。统计学显著性定义为P<0.05。
在142例行经阴道宫颈环扎术的妇女中，38%发生环扎失败。失败组出生时的平均孕周为29.3±5.2周，而未失败组为37.9±2.8周（P<0.001）。单因素分析确定宫颈长度（P=0.034）和UCA 3（P<0.001）与出生时的孕周显著相关。受试者工作特征曲线显示，与宫颈长度为25 mm相比，UCA 3=108时对34周前分娩的预测能力有所提高（敏感性97%，特异性65%）。在<28周时，UCA 3在112时表现最佳（敏感性100%，特异性62%），而宫颈长度为25 mm时（敏感性29%，特异性39%）。二元逻辑回归显示，UCA 3>108时，34周前分娩的比值比为35.1（95%可信区间7.7至160.3），UCA 3>112时，28周前分娩的比值比为42.0（95%可信区间5.3至332.1）。相比之下，宫颈长度<25 mm时，34周前分娩的比值比为4.7（95%可信区间1.8至12.2），28周前分娩的比值比为6.0（95%可信区间1.9至19.3）。
在经阴道宫颈环扎术患者中，子宫颈前角越来越钝反映了孕中期环扎失败风险增加。将子宫颈前角测量作为一种监测工具可能会改善对环扎失败风险患者的识别。
