Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
Am J Obstet Gynecol. 2021 Jul;225(1):81.e1-81.e9. doi: 10.1016/j.ajog.2021.01.017. Epub 2021 Jan 25.
Occiput posterior position is the most frequent cephalic malposition, and its persistence at delivery is associated with a higher risk of maternal and perinatal morbidity. Diagnosis and management of occiput posterior position remain a clinical challenge. This is partly caused by our inability to predict fetuses who will spontaneously rotate into occiput anterior from those who will have persistent occiput posterior position. The angle of progression, measured with transperineal ultrasound, represents a reliable tool for the evaluation of fetal head station during labor. The relationship between the persistence of occiput posterior position and fetal head station in the second stage of labor has not been previously assessed.
This study aimed to evaluate the role of fetal head station, as measured by the angle of progression, in the prediction of persistent occiput posterior position and the mode of delivery in the second stage of labor.
We recruited a nonconsecutive series of women with posterior occiput position diagnosed by transabdominal ultrasound in the second stage of labor. For each woman, a transperineal ultrasound was performed to measure the angle of progression at rest. We compared the angle of progression between women who delivered fetuses in occiput anterior position and those with persistent occiput posterior position at delivery. Receiver operating characteristics curves were performed to evaluate the accuracy of the angle of progression in the prediction of persistent occiput posterior position. Finally, we performed a multivariate logistic regression to determine independent predictors of persistent occiput posterior position.
Overall, 63 women were included in the analysis. Among these, 39 women (62%) delivered in occiput anterior position, whereas 24 (38%) delivered in occiput posterior position (persistent occiput posterior position). The angle of progression was significantly narrower in the persistent occiput posterior position group than in women who delivered fetuses in occiput anterior position (118.3°±12.2° vs 127.5°±10.5°; P=.003). The area under the receiver operating characteristics curve was 0.731 (95% confidence interval, 0.594-0.869) with an estimated best cutoff range of 121.5° (sensitivity of 72% and specificity of 67%). On logistic regression analysis, the angle of progression was found to be independently associated with persistence of occiput posterior position (odds ratio, 0.942; 95% confidence interval, 0.889-0.998; P=.04). Finally, women who underwent cesarean delivery had significantly narrower angle of progression than women who had a vaginal delivery (113.5°±8.1 vs 128.0°±10.7; P<.001). The area under the receiver operating characteristics curve for the prediction of cesarean delivery was 0.866 (95% confidence interval, 0.761-0.972). At multivariable logistic regression analysis including the angle of progression, parity, and gestational age at delivery, the angle of progression was found to be the only independent predictor associated with cesarean delivery (odds ratio, 0.849; 95% confidence interval, 0.775-0.0930; P<.001).
In fetuses with occiput posterior at the beginning of the second stage of labor, narrower values of the angle of progression are associated with higher rates of persistent occiput posterior position at delivery and a higher risk of cesarean delivery.
枕后位是最常见的头位异常，其在分娩时持续存在与母婴发病率升高相关。枕后位的诊断和处理仍然是临床挑战。这在一定程度上是由于我们无法预测哪些胎儿会自发旋转为枕前位，哪些会持续为枕后位。经会阴超声测量的进展角是评估分娩时胎头位置的可靠工具。枕后位在第二产程中与胎头位置的关系尚未被评估。
本研究旨在评估进展角（通过经会阴超声测量）在预测第二产程中持续枕后位和分娩方式中的作用。
我们招募了在第二产程中通过经腹超声诊断为枕后位的非连续系列孕妇。对于每位女性，均进行经会阴超声检查以测量休息时的进展角。我们比较了在第二产程中分娩为枕前位和持续为枕后位的孕妇的进展角。进行受试者工作特征曲线分析以评估进展角预测持续枕后位的准确性。最后，我们进行了多元逻辑回归分析以确定持续枕后位的独立预测因素。
共有 63 名女性被纳入分析。其中，39 名（62%）孕妇分娩为枕前位，24 名（38%）分娩为枕后位（持续枕后位）。在持续枕后位组中，进展角明显比分娩为枕前位的孕妇更窄（118.3°±12.2°比 127.5°±10.5°；P=.003）。受试者工作特征曲线下面积为 0.731（95%置信区间，0.594-0.869），估计最佳截断范围为 121.5°（灵敏度为 72%，特异性为 67%）。多元逻辑回归分析发现，进展角与持续枕后位独立相关（比值比，0.942；95%置信区间，0.889-0.998；P=.04）。最后，行剖宫产的孕妇的进展角明显比行阴道分娩的孕妇更窄（113.5°±8.1 比 128.0°±10.7；P<.001）。预测剖宫产的受试者工作特征曲线下面积为 0.866（95%置信区间，0.761-0.972）。在包括进展角、产次和分娩时的孕周的多变量逻辑回归分析中，进展角是唯一与剖宫产相关的独立预测因素（比值比，0.849；95%置信区间，0.775-0.0930；P<.001）。
在第二产程开始时为枕后位的胎儿中，进展角的较小值与分娩时持续为枕后位的发生率更高和剖宫产风险更高相关。
