Transvaginal ultrasonography in patients at risk for ectopic pregnancy

Transvaginal ultrasonography was performed in 139 patients at risk for ectopic pregnancy. Among these patients, 22 ectopic pregnancies and 117 intrauterine pregnancies were eventually confirmed. Transvaginal ultrasonography definitively identified 18 of 22 (82%) ectopic pregnancies at initial evaluation by either direct visualization of an ectopically placed gestational sac (N = 14) or failure to visualize an intrauterine gestational sac combined with a level of the beta-subunit of human chorionic gonadotropin greater than 1300 mIU/ml (First International Reference Preparation) (N = 4). Transvaginal ultrasonography definitively diagnosed 103 of 117 (88%) intrauterine pregnancies at initial evaluation. Eighteen patients could not be definitively diagnosed by transvaginal ultrasonography at initial evaluation because nonvisualization of a gestational sac and a beta-subunit of human chorionic gonadotropin value less than 1300 mIU/ml. Evaluation of this group with serial measurements of beta-subunit of human chorionic gonadotropin, repeat ultrasonography, or both, revealed ectopic gestation (N = 4), early intrauterine pregnancy (N = 4), and complete abortion (N = 10).