Endometrial Thickness Measured by Ultrasound Scan in Women with Uterine Outlet Obstruction Due to Intrauterine or Upper Cervical Adhesions

Background: A subgroup of women with Asherman's syndrome has adhesions of limited extent completely blocking the lower uterine cavity or upper cervix, whereas the upper endometrium remains normal. Haematometra are rarely found in these women. We tested the hypothesis that women with localized adhesions occluding the uterine outlet (but not affecting the upper uterine cavity) will have much thinner endometrium than controls.

Methods: Twenty-six women with Asherman's syndrome (16 with limited outlet adhesions only) and 50 with normal menstrual cycles underwent transvaginal ultrasound scan where endometrial double thickness was measured precisely and the cycle phase assessed. The presence of any fluid in the uterine cavity was noted.

Results: The endometrium in women with Asherman's syndrome, in whom uterine outlet blockage was the sole abnormality (subgroup 3), was substantially thinner (mean +/- SEM: 3.9 +/- 0.4 mm) than controls (8.5 +/- 0.05; P < 0.001), and haematometra were very uncommon (1 of 16). Endometrial thickness at all stages of the ovarian/menstrual cycle in all three subgroups of Asherman's syndrome was significantly less than in normal menstruating controls.

Conclusions: Non-invasive ultrasound measurements have demonstrated very thin endometrium and absence of haematometra in most women with uterine outlet occlusion by adhesions. This unusual phenomenon of failure of cyclical endometrial growth and breakdown in the sole presence of cervical occlusion by adhesions merits further study.