Role of routine ultrasonography in monitoring the outcome of medical abortion in a clinical setting

Background. Clinical methods generally used to evaluate the completeness of medical abortion are not accurate. There are no published reports evaluating the role of routine ultrasonography in monitoring the outcome of medical abortion. The purpose of this study was to investigate whether routine transvaginal ultrasonography (TVS) at the follow-up visit after medical abortion can accurately identify women who will require surgical intervention. Design. Retrospective review of medical records and charts of all women undergoing medical abortion in the first trimester of pregnancy between January 1999 and December 2001. Methods. Medical abortion was performed using oral mifepristone and a vaginal prostaglandin analog before 63 days gestation. All women had an initial TVS to confirm intrauterine pregnancy and gestational age, and another TVS at the follow-up visit 2-3 weeks later to assess the completeness of abortion. Surgical evacuation of the uterus was allowed as indicated on clinical grounds but not on the basis of ultrasound findings only. Results. A total of 690 women consented to medical abortion during the study period. Eleven of these women were excluded from the study for various reasons. Of the remaining 679 cases, 95% (645/679) had a documented follow-up at the hospital. The pregnancy termination rate among these women was 99.2% (640/645) and TVS identified all five cases of continuing pregnancy at the follow-up. A total of 66 (10.2%) patients had complications. The uterine cavity was empty on TVS at the follow-up visit in 84.8% (547/645) of cases and only 3.1% (17/547) of them required surgical aspiration/curettage due to excessive or prolonged vaginal bleeding. In the remaining 15.2% (98/645) the uterine cavity was not empty, and 43.9% (43/98) of them had a curettage. The risk of requiring a surgical intervention was significantly higher [odds ratio (OR) 24.4; 95% confidence interval (95% CI) 14.9-39.7] when the uterine cavity was not demonstrated to be empty at the follow-up visit 2-3 weeks after medical abortion. However, 59.1% (55/93) of women did not require surgical intervention despite ultrasound evidence of thick endometrial echo-complex. Conclusion. Routine TVS 2-3 weeks after medical abortion appears to be an efficient means of accurately identifying the cases of ongoing pregnancy and diagnosing a complete abortion. Although TVS could be used as an adjunct to clinical examination to diagnose an incomplete expulsion, it does not accurately differentiate those women who require surgical intervention from those who do not.