Analysis of ultrasonographic criteria in the evaluation for ectopic pregnancy.

To assess the usefulness of ultrasound in diagnosing ectopic pregnancy, the ultrasonographic findings, pregnancy test results, and proven diagnoses in 148 patients referred for evaluation for ectopic pregnancy were reviewed. Of these patients, 33 were subsequently proven to have ectopic gestations. The ultrasonograms were coded for uterine size, intrauterine gestation sac, adnexal mass, adnexal ring, cul-de-sac fluid, or normal findings. With a positive pregnancy test, the presence of an intrauterine gestation sac excludes the diagnosis of ectopic pregnancy. Of those patients with positive pregnancy tests and no intrauterine gestation sac, 73% had ectopic pregnancy. All patients with normal ultrasonograms had other diagnoses. With a negative pregnancy test, the intrauterine findings are not helpful, and evaluation of the adnexa is more important. An adnexal ring is a significant, though not absolute, indicator of ectopic pregnancy. A normal scan excludes this diagnosis. Other criteria were not significant. A clinical approach to the evaluation for ectopic pregnancy, based on the data accumulated in this study, is suggested.