Transvaginal ultrasonography of the endometrium in women with postmenopausal bleeding--a Nordic multicenter study

The purpose of this study was to use transvaginal ultrasonographic measurements to find the thickness of the endometrium below which the risk of endometrial abnormality in women with postmenopausal bleeding is low.

This multicenter study was carried out at eight clinics in four Nordic countries. The study included 1168 women with postmenopausal bleeding scheduled for curettage Before the curettage was performed, the thickness of the endometrium was measured with transvaginal ultrasonography. The measurement included both endometrial layers (double-layer technique). The transvaginal ultrasonographic measurement was compared with the histopathologic diagnosis of the curettage specimens.

In women with atrophic endometrium the mean endometrial thickness (+/- SD) was 3.9 +/- 2.5 mm. The corresponding figures for women with endometrial cancer were 21.1 +/- 11.8 mm. No malignant endometrium was thinner than 5 mm. In 30 women (2.8%) it was not possible to measure the thickness of the endometrium; one of these women had endometrial cancer. The 95% confidence limit for the probability of excluding endometrial abnormality was 5.5% when the endometrial thickness was < or = 4 mm as measured by transvaginal ultrasonography.

The risk of finding pathologic endometrium at curettage when the endometrium is < or = 4 mm as measured by transvaginal ultrasonography is 5.5%. Thus in women with postmenopausal bleeding and an endometrium < or = 4 mm it would seem justified to refrain from curettage.