Presence of a Yolk Sac on Transvaginal Sonography Is the Most Reliable Predictor of Single-Dose Methotrexate Treatment Failure in Ectopic Pregnancy

Abstract

The purpose of this study was to determine which imaging characteristics can be used as prognostic indicators in conjunction with beta-human chorionic gonadotropin (beta-hCG) levels in the treatment of ectopic pregnancy (EP) with single-dose methotrexate (MTX). A retrospective study was performed on 62 patients (age range, 16-47 years; mean, 29 years) treated with MTX for EP from November 2000 to August 2003. The transvaginal sonographic findings in each case were analyzed for the presence and size of an extraovarian mass or a pseudogestational sac, amount of free fluid, presence of a yolk sac, and fetal heart motion. Patient age and beta-hCG level were also noted. Success of treatment was defined as a single dose of MTX that resulted in appropriate lowering of beta-hCG levels. Of 62 patients, 17 (27%) had single-dose MTX treatment failure. A yolk sac was identified in 15 (88%) of the 17 treatment failures and in none of the cases in which treatment was successful (positive predictive value, 100%). The average beta-hCG level in the cohort of patients who had single-dose treatment failure was 3282 mIU/mL compared with 1544 mIU/mL in the treatment success cohort. The presence of fetal heart motion was seen in only 1 patient, and this patient had treatment failure. The age of the patient, size of the extraovarian mass, presence of a pseudogestational sac, and amount of free fluid did not correlate with outcome. The presence of a yolk sac was always associated with treatment failure in single-dose MTX treatment of EP and was the most reliable predictor of failure among all features analyzed. The beta-hCG level was a useful adjunct. A prediction rule was created correlating the probability of treatment success with the beta-hCG level.