Diagnosis of ectopic pregnancy: endovaginal vs transabdominal sonography

During a 25-month period, 193 women with the clinical diagnosis of suspected ectopic pregnancy had transabdominal and endovaginal sonograms. Most had quantitative determinations of serum human chorionic gonadotropin (HCG). Endovaginal sonography was diagnostic of ectopic pregnancy in 23 (38%) of the 60 patients with surgically proved ectopic pregnancies: transabdominal sonography was diagnostic in 13 patients (22%). All 83 intrauterine pregnancies were identified with endovaginal sonography, compared with 34 identified with transabdominal sonography. Endovaginal sonography was somewhat more helpful in the diagnosis of missed abortion and blighted ovum. Eighty endovaginal sonograms were classified as indeterminate as compared with 141 transabdominal studies. This indeterminate group included patients with complete abortions, ectopic pregnancies without sonographic evidence of an extrauterine gestation, incomplete abortions, and patients with subsequent negative serum levels. As in prior reports, endovaginal sonography was superior to transabdominal sonography in the evaluation of suspected ectopic pregnancies. Overall, endovaginal sonography was diagnostic in 113 patients, whereas transabdominal sonography was diagnostic in 52 patients. The finding of an extrauterine fetal pole or embryo was diagnostic for an ectopic pregnancy. Pelvic fluid, the appearance of the endometrium, and a single positive serum HCG determination were not helpful in making the diagnosis of ectopic pregnancy.