Ectopic pregnancy: criteria and accuracy of ultrasonic diagnosis.

Of 26 ectopic pregnancies, a correct positive ultrasonic diagnosis was made in 77%, while a false negative diagnosis was made in 23%. Most commonly, the ectopic pregnancy appeared as a complex adnexal mass immediately adjacent to an enlarged "empty" uterus. Ultrasonic identification of an extrauterine gestational sac, allowing a definitive diagnosis of ectopic pregnancy, was uncommon.