EndomThickness Measured w/Trans-Vag Sono

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?

Dueholm M, Jensen ML, Laursen H, Kracht P Acta Obstet Gynecol Scand. 2001;80:645-651


Transvaginal sonography alone is not sufficient in the evaluation of abnormal uterine bleeding in premenopausal patients. This study did not determine an optimal endometrial thickness that could be used as a cut-off value to differentiate normal from abnormal endometrium. Abnormal uterine bleeding is commonly caused by benign changes (polyp, submucous myoma) in premenopausal women.

Although endometrial biopsies may not identify such lesions, they are commonly used to rule out hyperplasia or cancer as the source of abnormal bleeding. This study evaluated the use of transvaginal sonography in the evaluation of abnormal uterine bleeding in premenopausal women.

The ultrasound results were compared with findings of hysteroscopy or sonohysterography combined with biopsies. Hysteroscopy or sonohysterography with biopsy was considered a true value. Various endometrial thickness levels, as cut-off, were assessed to rule out endometrial abnormalities.

A total of 470 patients with abnormal uterine bleeding were enrolled at 2 different study sites in a prospective manner. Participants were evaluated with transvaginal sonography and sonohysterography. Biopsy was obtained from women over age 45 years and with menorrhagia, from women over 40 years and with metrorrhagia, and from women over 35 years and with abnormal uterine bleeding. Biopsy was obtained by either dilatation and curettage or by aspiration biopsy.

Ninety-seven patients did not require biopsy according to the above mentioned guidelines. Of the 355 patients who had biopsies, 189 had an operative procedure (hysterectomy or operative hysteroscopy) as well. If a patient had an operative procedure, the finding of the operative procedure was considered the true value. If the patient had a sonohysterography followed by biopsy but no operative procedure, then these results were considered the true values.

Endometrial thickness was measured in 329 out of 355 patients. Forty-two percent of the patients had abnormalities. Patients with submucous myomas had thinner endometria than patients without any abnormalities. Women with endometrial hyperplasia or endometrial polyps had thicker endometria than those without abnormalities. The use of different endometrial thickness cut-off values to differentiate normal from abnormal endometrium did not increase the probability of identifying abnormalities (polyp, hyperplasia, or myoma).

Receiver operating characteristic (ROC) analysis did not find an optimal endometrial thickness that identified abnormalities with high sensitivity and specificity. Transvaginal sonography alone is not sufficient in the evaluation of abnormal uterine bleeding in premenopausal patients.

Clinical commentary

Abnormal uterine bleeding is a common reason for gynecologic visits by premenopausal women. Although many of these cases have a benign etiology, the possibility of malignancy must be kept in mind especially for perimenopausal women.

The uterus and the endometrium can be assessed with invasive and noninvasive methods. Noninvasive methods can describe the homogeneity and thickness of the endometrium, and certain tests (eg, sonohysterography) can provide details about focal intrauterine pathology.

Several studies have tried to establish endometrial thickness cut-off values that differentiate between normal and abnormal endometria with high specificity and sensitivity. Among postmenopausal patients, the use of such cut-off values is associated with high negative predictive values but with lower positive predictive values.

It is especially difficult to establish such cut-off values for premenopausal women, as the endometrium undergoes constant changes as a result of cyclic hormonal stimulation. Endometrial thickness varies in different phases of the cycle.

This study enrolled 470 patients who were referred to bleeding disorder clinics with abnormal uterine bleeding. Twenty percent of the patients were not evaluated with biopsies. The reason for bleeding in these cases was not explained. The remaining 80% were evaluated with either hysteroscopy and biopsy or sonohysterography and biopsy.

Other studies have already shown that diagnostic hysteroscopy and sonohysterography are equally effective in assessing the endometrium, but to improve diagnostic accuracy they need to be combined with endometrial sampling. This study found that the endometrium is thinner when submucous myoma is present and thicker with polyps and hyperplasia.

However, the study did not find an endometrial thickness cut-off value that helped the diagnosis of abnormalities. Setting a low cut-off value will improve the diagnosis of various abnormalities, but it will also lead to many unnecessary interventions. Setting a high cut-off value will reduce the false-positive results, but more abnormalities will be missed.

Currently, there is no accepted cut-off value for premenopausal women with abnormal uterine bleeding that could differentiate normal from abnormal endometrium. The use of sonohysterography can improve the diagnosis of focal endometrial lesions. None of these diagnostic tests, however, can replace the use of biopsies for the diagnosis of endometrial abnormalities.

Acta Obstetrica et Gynecologica Scandinavica July 2001 (Volume 80, Number 7)

Comments by as Associate Professor of Ob-Gyn Univ S Florida

From an email, 11/04

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