Jirapinyo M, Ajjimakorn S
Department of Obstetrics & Gynaecology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
J Med Assoc Thai. 1990 Feb;73 Suppl 1:69-72.
From 1,000 ultrasonographic examinations reviewed there were 80 (8%) done for the exclusion of placenta previa. Only 83.6 per cent of these had complete medical records and were the subjects of this study. The most common reason for requesting ultrasonography was antepartum hemorrhage (79.1%). False-positive and false-negative of the report were 16.7 per cent and at least 4.2 per cent respectively. Based on the theory of placental migration it can be recommended that a minor degree of placenta previa diagnosed in the early stage of pregnancy does not need follow-up scanning while the diagnosis of placenta previa totalis follow-up scanning is imperative. A judicious decision in the combined usage of ultrasonography and double-set-up technique can reduce the risk of brisk bleeding and unnecessary cesarean section.
在回顾的1000例超声检查中，有80例（8%）是为排除前置胎盘而进行的。其中只有83.6%有完整的病历记录，成为本研究的对象。要求进行超声检查的最常见原因是产前出血（79.1%）。报告的假阳性率和假阴性率分别为16.7%和至少4.2%。根据胎盘迁移理论，建议妊娠早期诊断为轻度前置胎盘者无需进行随访扫描，而完全性前置胎盘则必须进行随访扫描。明智地联合使用超声检查和双合诊技术可以降低大出血风险和不必要的剖宫产风险。
