By Alaa Elzarka MD, PhD, OB GYN Lecturer, Alexandria Faculty of Medicine

Abnormal uterine bleeding is considered a common problem for women during their childbearing period. However, it entails a lot of worries for patients and physicians when it is noticed at the age of menopause.

Post-menopausal uterine bleeding has multiple causes including endometrial cancer; therefore, it must be investigated thoroughly. Although less than 10% of post-menopausal bleeding is caused by endometrial cancer, this possibility must be ruled out. There are a lot of tools to evaluate such conditions, one of these is pelvic ultrasonography.

Risk factors that could be considered in assessment of menopausal women include obesity, diabetes, hypertension, and family history of gynecological cancers. Pelvic ultrasound should be the first diagnostic tool for evaluation of post-menopausal bleeding for reasons that will be covered in the following review.

First, an ultrasound scan is widely available, noninvasive, and harbors little or no hazards for patients. Therefore, it has been recognized as the first step in diagnosis of post-menopausal uterine bleeding by the American College of Obstetrics and Gynecology (ACOG) (1).

Endometrial thickening is the most important predicting factor for endometrial cancer in postmenopausal women. It can be measured easily and accurately using endovaginally ultrasound scan (2). The scan results may direct the physician toward the appropriate second step of management, which is performing endometrial sampling.  Sampling of the endometrial lining is a crucial step in diagnosing the cause of bleeding. However, this step might be deferred if the initial endometrial thickness is equal to or less than 4 mm, resulting in a lower risk of endometrial cancer at that time. Using a detailed endometrial scan will determine the possibility of having an abnormal endometrial lining that requires tissue sampling to rule out endometrial cancer.

Aside from endometrial thickening, other sonographic exam features beyond 2D imaging could be helpful in predicting endometrial cancer. These include sonographic homogeneity, smoothness of endometrial myometrial junction, and presence of vascularity on color Doppler within the endometrial lining. For example, a thin homogenous endometrium might be present in atrophic endometrium. Conversely, thick cystic endometrial lining might be present in hyperplastic endometrium (3).

Furthermore, careful sonographic examination  of the endometrial lining is required to determine the method of sampling. For example, suspected focal lesion in the uterine cavity might require essential hysteroscopic guidance in sampling.

The POCUS detailed endovaginal scan is useful to get the maximum high-resolution image of the uterine cavity.
Listed below is how you can perform a detailed ultrasound examination  of the endometrial lining in a few steps:

• Select the appropriate probe for examination, the transvaginal scan is better for pelvic scan.
• Follow the hospital policy for disinfection and probe cleaning.
• For better evaluation, the patient should be examined after bladder emptying.
• The longitudinal plane of the uterus should be examined from side to side.
• Measuring the maximum endometrial thickness in the mid-sagittal plane using the anterior posterior maximum diameter.
• Rotate the vaginal probe 90 degrees to assess the transverse uterine plane.
• Sweep the probe from the fundus to the cervix in the transverse plane.
• Apply color Doppler to evaluate vascularity.
• At some point a 3D scan might be required for evaluation of intracavitary lesions.

In view of the above, the POCUS endovaginal pelvic scan is the cornerstone in diagnosing cases with post-menopausal vaginal bleeding because it represents a widely available and safe assessment of the endometrial lining. This  can be helpful in selecting cases that need further action in management– in the form of hysteroscopy, and it can  rule out other pelvic pathology.

References

1. ACOG committee opinion no. 734: the role of transvaginal ultrasonography in evaluating the endometrium of women with postmenopausal bleeding. Obstet Gynecol. 2018 May;131(5):e124–9.
2. Long B, Clarke MA, Morillo ADM, Wentzensen N, Bakkum-Gamez JN. Ultrasound detection of endometrial cancer in women with postmenopausal bleeding: Systematic review and meta-analysis. Gynecol Oncol. 2020 Jun;157(3):624–33.
3. Van Den Bosch T, Verbakel JY, Valentin L, Wynants L, De Cock B, Pascual MA, et al. Typical ultrasound features of various endometrial pathologies described using International Endometrial Tumor Analysis (IETA) terminology in women with abnormal uterine bleeding. Ultrasound Obstet Gynecol. 2021 Jan;57(1):164–72.