Prediction of late failure after medical abortion from serial beta-hCG measurements and ultrasonography.

BACKGROUND Surgical treatment of failed medical abortion may be performed several weeks after initiation of the abortion. There are no recognized methods for early identification of these late failures. We assessed the prognostic values of beta-hCG and ultrasonography in predicting late failure after medical abortion. METHODS A total of 694 consecutive women with gestational age (GA) <63 days were followed up with beta-hCG measurements initially on the day of treatment and on day 8 and day 15, after the medically induced abortion with mifepristone and gemeprost. Measurement of the endometrial thickness by ultrasonography was performed on day 15 after induction of medical abortion. Failures diagnosed after day 15 and within 15 weeks were identified and classified as late failures. All interventions in this group were due to bleeding problems. The predictive values of different absolute and relative beta-hCG levels and different endometrial thickness were analysed. RESULTS Of all failures in the study period, 65% (32) were diagnosed after the 2 week follow-up, and categorized as late failures. The absolute and the relative beta-hCG values on days 8 and 15 as well as the endometrial thickness on day 15 were greater among late failures than successes. Used as a predictive test, the positive predictive values of these variables were low. CONCLUSION Neither beta-hCG nor endometrial thickness can be used clinically as diagnostic tests in predicting late failure after medical abortion.