Vaginal sonography in ectopic pregnancy. A prospective evaluation.

Among 404 first-trimester pregnancies examined with vaginal sonography in a prospective study, there were 21 ectopic gestations. Considering only the initial scans, the endometrial canal showed a linear echo surrounded by an echogenic zone in 18 cases, but in three cases the uterine cavity demonstrated a small echo-free area representing blood. Free fluid within the cul-de-sac was seen in 17 patients. An adnexal tumor representing the extrauterine gestation, was detected in 19 cases. Fifteen of these masses exhibited a thick-walled ring characteristic of a gestational sac with a viable embryo in five cases and a yolk sac in one. Other cystic adnexal masses, such as corpus luteum cysts, seen in 14 of the 21 patients were not confused with the ectopic pregnancy. A correct tentative diagnosis of ectopic gestation was made in 18 patients (86%) after the initial scan and in 20 cases (95%) including four controls. There was one false-positive suspicion of ectopic gestation in a patient who actually had a spontaneous abortion. Interpretation of the sonographic image should generally be done in correlation with laboratory and clinical data. The results of the study indicate that vaginal sonography is a valuable diagnostic procedure in the evaluation for ectopic pregnancy.