Accuracy of transvaginal ultrasound and serum hCG in the diagnosis of ectopic pregnancy

Abstract

Transvaginal ultrasound was performed upon admission of 127 patients with a clinical suspicion of ectopic pregnancy in association with human chorionic gonadotropin (hCG) determination. Failure to visualize with sonography an intrauterine gestational sac with an hCG level superior to 1000 mIU/ml identified 25/42 tubal pregnancies with a positive predictive value of 86% and a specificity of 93%. Abnormal adnexal findings occurred in 95% of the ectopic pregnancies. Extrauterine gestational sacs with or without embryos could be confidently detected in 19 ectopic pregnancies (45%). A complex adnexal mass was seen in 19 cases and yielded a positive predictive value of 90% (19/21). Adnexal gestational sacs and complex masses were seen more frequently in those ectopic pregnancies with an hCG level above 1000 mIU/ml but the difference was not significant (100% versus 78%). Simple adnexal cysts were found more frequently in intrauterine pregnancies, and fluid in the cul-de-sac was also not indicative of ectopic pregnancy (positive predictive value, 29%). Transvaginal ultrasound has a primary role in the diagnosis of ectopic pregnancy. The combined use of uterine and adnexal sonography associated with elevated hCG levels allows a definitive diagnosis in the vast majority of cases at a very early stage, when the chances for a successful conservative treatment are greater.