Lauria M R, Smith R S, Treadwell M C, Comstock C H, Kirk J S, Lee W, Bottoms S F
Department of Obstetrics and Gynecology, Wayne State University, Grace and Hutzel Hospitals, Detroit, MI, USA.
Ultrasound Obstet Gynecol. 1996 Nov;8(5):337-40. doi: 10.1046/j.1469-0705.1996.08050337.x.
Our objective was to determine the incidence and rate of persistence of placenta previa diagnosed at 15-20 weeks' gestation by using transvaginal sonography (TVS), and to describe the characteristics of TVS that predict placenta previa at delivery. Patients having placental tissue within 20 mm of the cervical os were prospectively identified by transabdominal ultrasound and underwent TVS. The distance of the placental edge from the cervical os was measured in millimeters. Characteristics of TVS predicting placenta previa at delivery were analyzed by logistic regression. The incidence of placenta previa diagnosed by TVS at 15-20 weeks was 1.1%; 14% persisted until delivery. Gestational age at the time of TVS and the distance of the placental edge to the cervical os helped predict placenta previa at delivery. Between 15 and 24 weeks' gestation, placenta overlapping the internal os by > or = 10 mm identified patients at risk of placenta previa at delivery with 100% sensitivity and 85% specificity. The use of TVS in the second trimester to diagnose placenta previa resulted in a lower incidence than was historically reported with the use of transabdominal ultrasound. The distance of the placental edge from the cervical os helps identify patients at risk of previa at delivery.
我们的目的是通过经阴道超声检查（TVS）确定妊娠15 - 20周时诊断出的前置胎盘的发生率和持续率，并描述在分娩时预测前置胎盘的TVS特征。通过经腹超声前瞻性地识别宫颈内口20mm范围内有胎盘组织的患者，并进行TVS检查。以毫米为单位测量胎盘边缘与宫颈内口的距离。通过逻辑回归分析TVS预测分娩时前置胎盘的特征。TVS在15 - 20周时诊断出的前置胎盘发生率为1.1%；14%持续至分娩。TVS检查时的孕周以及胎盘边缘与宫颈内口的距离有助于预测分娩时的前置胎盘。在妊娠15至24周之间，胎盘覆盖宫颈内口≥10mm可识别出有分娩时前置胎盘风险的患者，敏感性为100%，特异性为85%。在孕中期使用TVS诊断前置胎盘的发生率低于历史上经腹超声检查报告的发生率。胎盘边缘与宫颈内口的距离有助于识别有分娩时前置胎盘风险的患者。
