Can the endometrial thickness as measured by trans-vaginal sonography be used to exclude polyps or hyperplasia in pre-menopausal patients with abnormal uterine bleeding?

BACKGROUND: To combine findings of normal mid-line echoes from TVS (trans-vaginal sonography) with cut-off levels for endometrial thickness, in order to examine the associated risk of abnormalities in the uterine cavity.

DESIGN AND SETTING: Two center prospective study at a university clinic and a central hospital in Denmark.

PARTICIPANTS: Three hundred and fifty-five pre-menopausal patients with abnormal uterine bleeding, and indications for endometrial sampling or surgery.

INTERVENTIONS: The thickness of the endometrium was measured, and the mid-line echoes were evaluated using TVS. The findings from the endometrial sampling, combined with the evaluation of the uterine cavity using operative hysteroscopy (115), hysterectomy (74) or HSE (hysterosonographic examination) (166), were used as the true values.

RESULTS: The mean (+/-s.d.) endometrial thickness was significantly different in patients with hyperplasia 11.5 mm (+/-5.0), polyps 11.8 mm (+/-5.1), sub-mucous myomas 7.1 mm (+/-3.4) and in patients without these abnormalities 8.37 (+/-3.9) (p<0.001). Hyperplasia and/or polyps were present in 20% of all patients, and in 8% of 143 patients with an endometrial thickness of < or =7 mm. This proportion did not decrease with lower cut-off levels for endometrial thickness. Receiver operating characteristic (ROC) curves were not optimal for excluding hyperplasia or polyps by endometrial thickness. In 173 cases with a distinct, regular midline echo without echo-dense foci in TVS the proportion of patients with abnormalities was 16% (11-23). This proportion did not decrease with cut-off levels for endometrial thickness.

CONCLUSIONS: Using TVS, low levels of endometrial thickness reduced the possibility of abnormalities such as polyps and hyperplasia, but did not exclude them. Low cut-off levels for endometrial thickness did not increase the diagnostic performance in cases with normal sonograms.