分娩第二期における経会陰超音波検査の有用性の検討 －子宮口全開大直後の分娩進行の評価による自然分娩の予測―

摘要

Purpose To investigate whether transperineal ultrasound examination just after full cervical dilatation is determined can predict the mode of delivery. Methods This was a prospective observational study of pregnant women. After full cervical dilatation was determined by vaginal examination during labor, transperineal ultrasound was immediately performed and the head direction (HD), progression distance (PD), and angle of progression (AoP) were measured. The cases were divided into two groups: spontaneous vaginal delivery and operative delivery due to failure of progression. Differences between the groups were statistically analyzed using Student’s t-test and Fisher’s exact test. Results Of the 50 women, 42 had spontaneous vaginal deliveries and 8 had vacuum extractions. The spontaneous delivery group had significantly higher HD, PD, and AoP values than the vacuum extraction group. The areas under the receiver-operating characteristic curves for the prediction of spontaneous vaginal delivery were 0.850 for HD, 0.827 for PD, and 0.783 for AoP. The optimum cut-off points and positive predictive values were 83° and 92.9% for HD, 56 mm and 94.9% for PD, and 146° and 94.3% for AoP, respectively. Conclusion Transperineal ultrasound examination just after full cervical dilatation was determined was useful in predicting spontaneous vaginal delivery.