Sonographic patterns of the endometrium in assessment of medical abortion outcomes.

BACKGROUND: We aimed to define endometrial pattern and endometrial thickness in predicting the outcome of early medical abortion.

STUDY DESIGN: While blinded to outcomes of abortion, we retrospectively reviewed the ultrasound scan performed 14-21 days after medical abortion. We assessed the endometrial pattern and endometrial thickness. A total of 943 women at or before 56 days of gestation who underwent medical abortions were included. Abortion was induced with mifepristone (600 mg) orally followed 48 h later with oral misoprostol (600 mcg). A successful medical abortion was defined as complete abortion without surgical intervention. Three sonographic patterns (homogenous, heterogeneous and multilayered) were devised to correlate with the outcome.

RESULTS: Of the 940 women, 92 (9.8%) had failed medical abortions. Eighty-seven (94.6%) patients with failed treatment outcomes had a heterogeneous pattern, while no patients with failed treatments had a multilayered pattern. Based on multivariable logistic regression, women who had an endometrial thickness in the range of 10-15 or >15 mm were more likely to have failed outcomes than those with a thickness <10 mm, with ORs of 3.69 (p=.001) and 8.82 (p<.001). Compared to those with a homogenous pattern, women with a heterogeneous endometrial pattern were more likely to have failed outcomes (OR 4.5, p=.003). In addition, an endometrial thickness >10 mm in combination with a heterogeneous pattern had the highest balanced accuracy in the prediction of failed outcome (81.9%; 95% CI, 77.6-86.3).

CONCLUSION: Women with a multilayered pattern could be reassured that they have successful medical abortion, while those with a heterogeneous pattern and/or endometrium >10 mm may need follow-up. Sonographic endometrial pattern and endometrial thickness may serve as objective criteria in the management of early medical abortions.