Eriç Horasanlı Jule, Demirbaş Nur, Mıngır Ülfet Sena, Güzelkara Ergene Beyza, Akkaş Niyazi
Department of Obstetrics and Gynecology, Faculty of Medicine, Necmettin Erbakan University, Konya, Turkey.
Department of Family Medicine, Faculty of Medicine, Necmettin Erbakan University, Konya, Turkey.
Int J Gynaecol Obstet. 2025 Jun 26. doi: 10.1002/ijgo.70338.
This study aimed to evaluate the diagnostic accuracy of the angle of progression (AOP), measured by ultrasound at the onset of the second stage of labor, as a predictor of spontaneous vaginal delivery in term singleton pregnancies, and to identify a cutoff value for the AOP angle that could predict normal delivery in women with occiput anterior (OA) cephalic presentation.
This prospective, observational study was carried out at a single tertiary center between February 2023 and January 2025. The study population consisted of patients at the beginning of the second stage of labor with a medical indication for vaginal delivery and enrolled after cervical preparation. Only full-term pregnancies with OA presentation were included. Transperineal ultrasound was used to measure the AOP during the second stage of labor. Sonographic findings from women who achieved spontaneous vaginal delivery were evaluated and subsequently compared with those of women who required cesarean section. Clinical data and delivery outcomes were retrieved from medical records.
A total of 162 patient applications were reviewed. Of these, 38 patients (23.46%) were not in active labor, and 28 patients (17.28%) underwent an emergency cesarean section (CS) before reaching active labor. Additionally, 17 patients (10.49%) had an operative vaginal delivery, while 79 patients (48.77%) had spontaneous vaginal delivery (SVD). Angle of progression was significantly different between the groups. The average AOP for CSs (118.00 ± 9.34) was narrower compared with SVDs (124.09 ± 7.58), with a statistically significant difference (P = 0.001). Logistic regression identified AOP as the most important predictor of delivery mode, with a 1° increase in AOP increasing the likelihood of SVD 0.9-fold (OR 0.916; P = 0.002). Receiver operating characteristic analysis showed that AOP had a moderate ability to predict SVD (area under the curve = 0.687; P = 0.003), with a cutoff value of AOP ≥123° offering 77.9% specificity and 89.5% sensitivity for predicting SVD in women.
The AOP measured by transperineal ultrasound at the beginning of the second stage of labor can predict SVD in term pregnancies and can be used in conjunction with physical examination and other clinical factors for the management of labor.
本研究旨在评估产程第二期开始时通过超声测量的进展角度（AOP）作为足月单胎妊娠自然阴道分娩预测指标的诊断准确性，并确定AOP角度的临界值，以预测枕前位（OA）头先露孕妇的正常分娩。
本前瞻性观察性研究于2023年2月至2025年1月在一家单一的三级中心进行。研究人群包括产程第二期开始时具有阴道分娩医学指征且在宫颈准备后入组的患者。仅纳入OA胎位的足月妊娠。在产程第二期使用经会阴超声测量AOP。对自然阴道分娩女性的超声检查结果进行评估，并随后与需要剖宫产的女性的结果进行比较。从病历中检索临床数据和分娩结局。
共审查了162份患者申请。其中，38名患者（23.46%）未进入活跃期，28名患者（17.28%）在进入活跃期前接受了急诊剖宫产（CS）。此外，17名患者（10.49%）进行了阴道助产，而79名患者（48.77%）自然阴道分娩（SVD）。两组之间的进展角度有显著差异。剖宫产组的平均AOP（118.00±9.34）比自然阴道分娩组（124.09±7.58）更窄，差异有统计学意义（P = 0.001）。逻辑回归确定AOP是分娩方式的最重要预测指标，AOP每增加1°，自然阴道分娩的可能性增加0.9倍（OR 0.916；P = 0.002）。受试者工作特征分析表明，AOP预测自然阴道分娩的能力中等（曲线下面积 = 0.687；P = 0.003），AOP≥123°的临界值对预测女性自然阴道分娩的特异性为77.9%，敏感性为89.5%。
产程第二期开始时经会阴超声测量的AOP可预测足月妊娠的自然阴道分娩，并可与体格检查和其他临床因素结合用于产程管理。
