Department of Diagnostic Radiology, Obstetrics and Gynecology1, College of Medicine, Yeungnam University, Taegu, Korea
ABSTRACT
Sometimes, the diagnosis of placenta previa by transabdominal ultrasonography may be difficult, especially inthe third trimester of pregnancy, because of obscuration of internal os of the cervix by overlying placenta asadvancing pregnancy. In such situations, however, the transperineal ultrasonography may offer an additional viewof internal os of the cervix without obscuration by overlying fetal parts or placenta. We evaluated forty pregnantwomen in whom placenta previa were suspected clinically, with both transabdominal and transperinealultrasonography. The menstrual age at the time of ultrasonography, ranged from 27 to 36 weeks. We compared thediagnostic accuracy of each procedure with the final diagnosis at the time of delivery. Transabdominalultrasonography provided to correct diagnosis in 25 cases. In remaining 15 cases, the confident diagnosis couldnot be made because of poor visualization of internal os of the cervix. However, transperineal ultrasonographyprovided the correct diagnosis in all 40 cases. We conclude that the transperineal ultrasonography is relativelyeasy and vonvenient technique and valuable for detection of placenta previa, especially when the diagnosis ofplacenta previa is difficult by transabdominal ultrasonography.