abnormal bleeding

Perimenopausal Bleeding

During the transition to menopause, women’s hormones can fluctuate, causing various types of vaginal bleeding. This bleeding can be light or heavy, regular or irregular. For women considering starting menopausal hormone therapy (MHT), any unusual bleeding should be checked out first. Heavy menstrual bleeding, rather than just irregular bleeding, is often a sign of an abnormal build-up of the uterine lining. 

Irregular bleeding is the cardinal symptom of perimenopause, but there are some types of bleeding that need exploration including bleeding between periods, after sex or associated with other, new symptoms such as pain or swelling. Sometimes it is difficult to separate the sources of bleeding between uterine, vaginal, bladder or even bowel.

Postmenopausal Bleeding

Postmenopausal bleeding is any vaginal bleeding that occurs 12 months after a woman’s last menstrual period (although rarely there may be a late ovarian hormone kick). This does not include the regular bleeding that can happen with MHT. Any postmenopausal bleeding should be checked to rule out serious causes.

Bleeding after menopause should always be taken seriously, whether or not someone is on MHT. There are many causes of postmenopausal bleeding, and while most are benign, bleeding may be a sign of cancer. The risk of endometrial cancer for women with bleeding ranges from 1-10%. About 90% of women diagnosed with endometrial cancer had at least one episode of postmenopausal bleeding before their diagnosis. This underscores the importance of ruling out endometrial cancer when this kind of bleeding occurs. Endometrial cancer can be effectively treated with surgery. Risk factors for endometrial cancer include atypical endometrial hyperplasia, unopposed oestrogen therapy, obesity, late menopause, nulliparity (no births), diabetes and tamoxifen use. 

One way to assess postmenopausal bleeding is by measuring the thickness of the uterine lining (endometrium) with a transvaginal ultrasound (an ultrasound with the probe in the vagina). If the thickness of the lining is ≤ 4 mm, the risk of endometrial cancer is believed to be less than 1%.  An ultrasound can detect uterine lesions such as polyps, fibroids, overgrowth of the endometrium (hyperplasia), or cancer.

The ≤ 4 mm measurement applies only when there is bleeding after menopause. If an ultrasound is done for another reason and the uterine lining is thicker than 4 mm, the cancer risk isn’t the same.  Six-10 mm is an acceptable cut-off when there isn’t any bleeding or other symptoms as the risk of cancer is exceptionally low.

For most women the ultrasound findings are sufficient for reassurance but there are important exceptions where a tissue sample or biopsy is needed to evaluate for precancerous or cancerous cells. These exceptions include:

• Recurrent bleeding after an initial evaluation with ultrasound.
• Presence of fibroids which can distort the lining, making the measurement unreliable.
• Significant risk factors for endometrial cancer such as taking tamoxifen or oestrogen without a progestogen.

Women on Menopausal Hormone Therapy

Women using cyclical MHT usually expect a withdrawal bleed, which happens at the end of the hormone cycle. If the bleeding is unpredictable, occurs outside the expected time, or is excessively heavy, it should be investigated.

Breakthrough bleeding is common during the first six months of continuous combined MHT (note that women without a uterus may be using oestrogen only MHT and are not at risk of endometrial cancer as the organ has been removed, MHT for women with a uterus will be “combined” and include progestogen as a capsule, patch or IUD). If bleeding occurs after this first 6 months and the MHT dose has been stable, it probably requires investigation, especially if it has been some years since the last natural period.

Causes of Postmenopausal Bleeding

Management

If a localised or cancerous lesion is found, surgery is the typical treatment.

For benign findings in women taking MHT, adjusting the MHT regimen may be necessary. If bleeding persists, re-investigation which often includes a biopsy, is advised.

• Cyclical MHT with unpredictable bleeding: Changing the type, dose, or delivery method of the progestogen component might help eg consider an IUD
• Continuous MHT with breakthrough bleeding and endometrial thickness >4mm: If less than 12 months post last menstrual period, switch to cyclical MHT or intrauterine progestogen (IUD). If more than 12 months, adjust the oestrogen/progestogen balance (excessive oestrogen can cause bleeding in a thickened endometrium).
• Continuous MHT with breakthrough bleeding and endometrial thickness <4mm: Switching back to cyclical MHT or increasing the oestrogen dose might help (excessive progestogen can cause persisting bleeding in an atrophic or thinned endometrium).

Surgery is appropriate for cancerous or problematic localised lesions. Heavy bleeding can be managed with specific progestogen therapy, IUD, a hysterectomy or endometrial ablation.