Verifying the effectiveness of medical abortion; ultrasound versus hCG testing

Abstract

Objectives: The combination of mifepristone and misoprostol is an established method for termination of pregnancy. However, there is no general agreement about how best to evaluate the treatment outcome.

Study design: In 217 women with an unwanted pregnancy below 49 days of amenorrhoea, ultrasound examination and serum hCG test were performed before treatment and at follow-up.

Results: Treatment was successful in 98.2%. At follow-up their hCG dropped to a mean of 3% (S.D. 3) of initial levels and the endometrium measured a mean of 10 mm (S.D. 4). Interpretation of endometrium was difficult in some cases because of inhomogeneous structure. Using hCG was reliable in 98.5% of successful abortions. For ultrasound the corresponding figure was 89.8% for the cases with a confirmed intrauterine pregnancy before treatment but only 66% if all pregnancies were included.

Conclusion: Measuring serum hCG before treatment and at follow-up is more effective than ultrasound to confirm a successful medically induced abortion in early pregnancy.