HRT and Endometriosis: Benefits and Risks for Women

Women with endometriosis who experience menopausal symptoms may benefit from hormone replacement therapy (HRT). However, the potential benefits must be carefully weighed against the specific health risks associated with the condition. 

Due to a lack of high-quality research, no official clinical guidelines have been established regarding HRT for endometriosis patients.⁽¹⁾ Doctor recommendations are often based on the patient’s severity of menopausal symptoms, health history, and personal preferences. It’s important for women diagnosed with endometriosis to receive comprehensive information about the benefits and risks of HRT in order to make informed decisions.

Research suggests a link between endometriosis and menopause, including a potential increased risk of early natural menopause.⁽²⁾ Estimated to affect over 6% of women of reproductive age in the United States⁽³⁾, endometriosis is a chronic disease that occurs when endometrial tissue, similar to that which lines the endometrium, grows outside of the uterus or elsewhere in the body. The condition commonly affects the ovaries and can cause symptoms of pelvic pain, severe menstrual cramps, and pain during sex or bowel movements.

Cases of endometriosis are most often seen in women in their 30s and 40s.⁽⁴⁾ However, women in perimenopause, menopause, or postmenopause can also be affected by the condition.

How HRT Affects Endometriosis

HRT is an effective treatment used to reduce vasomotor and vulvovaginal symptoms of menopause. It may also help lower the risk of osteoporosis as women age. HRT works by increasing levels of sex steroid hormones in the body that naturally fluctuate and drop as ovarian function declines during this phase of life. 

Estrogen is one of the main hormones used in HRT treatment. Levels of the hormone decrease significantly throughout menopause and postmenopause, dropping by more than 90% of premenopausal levels by the time women reach age 70.⁽⁵⁾ It may also influence the development of endometriosis. With less estrogen in the body to fuel endometriotic tissue growth, some women may find that their symptoms naturally lessen over time. Because endometriosis is an estrogen-dependent condition, increasing hormone levels through HRT may contribute to abnormal tissue growth or exacerbate symptoms.⁽¹⁾

Estrogen supplementation can provide substantial relief from a number of common menopausal symptoms. However, unopposed estrogen therapy may pose risks for women with a history of endometriosis.

Different Types of HRT for Women with Endometriosis 

Women experiencing bothersome menopausal symptoms may be prescribed different forms and doses of the following types of hormones:

• Estrogen

• Progesterone

Combined HRT with estrogen and progesterone is recommended for women with an intact uterus, including those with a history of endometriosis.⁽⁶⁾ It’s believed to be a safer option than estrogen-only therapy because the addition of progesterone reduces the risk of endometrial hyperplasia, uterine cancer, and reactivation of endometriotic tissue. Unopposed estrogen may increase the risk of these health issues. To counteract this, a synthetic progestin or oral micronized progesterone, a bioidentical hormone chemically identical to the progesterone naturally produced in the body, may be prescribed.⁽⁶⁾

Benefits and Risks of HRT for Women with Endometriosis

The benefits of HRT can significantly improve women’s quality of life. Treatment should not be ruled out solely because a woman has endometriosis. 

Menopausal women, with or without endometriosis, who receive HRT may experience relief from common menopausal symptoms, including the following:

• Hot flashes

• Night sweats

• Vaginal dryness

• Painful sex

• Mood changes

• Sleep disturbances

• Bone loss

However, it’s also possible that estrogen supplementation may trigger endometriotic tissue growth and increase the risk of endometriotic lesions becoming cancerous.⁽⁷⁾ Although the relative risk for ovarian cancer is higher in patients with endometriosis compared to those without the condition, the absolute risk is low overall. Women with severe cases of endometriosis or large ovarian endometriotic masses (endometriomas) may be at the highest risk for ovarian cancer.

Clinicians should take an individualized approach when determining whether the benefits of HRT outweigh the risks for women with endometriosis. Menopausal symptom severity, the risk of endometriosis reactivation, and HRT-related risk factors (such as a history of estrogen-dependent cancers like breast cancer) are all factors that should be taken into consideration.⁽⁷⁾⁽⁸⁾

How HRT Post-Hysterectomy Affects Endometriosis

A hysterectomy is a procedure in which the uterus is surgically removed. Some women may also have both ovaries removed, a procedure known as a bilateral oophorectomy. When this occurs, women enter surgically-induced menopause and may immediately begin experiencing symptoms such as hot flashes, vaginal dryness, or low libido.⁽⁹⁾

It’s recommended that women with endometriosis who have had their uterus removed receive continuous combined HRT with estrogen and progesterone for as long as needed to effectively treat menopausal symptoms and improve quality of life.

In some cases, a doctor may recommend switching to estrogen-only therapy as women age, as unopposed estrogen is believed to pose fewer risks in postmenopause. However, the potential risk of endometriotic tissue reactivation and cancer development should be considered if residual tissue remains after a hysterectomy.⁽⁹⁾

Women who undergo a bilateral oophorectomy and have minimal leftover endometriotic tissue after the procedure may have a lower risk of endometriosis reactivation and ovarian cancer associated with HRT use. For women who have had a hysterectomy and present with little residual disease, combined HRT followed by estrogen-only therapy may be recommended. In the event that endometriosis reactivates with HRT treatment, women should consult with a menopause specialist.⁽⁹⁾

Personalized HRT Treatment Plans for Women with Endometriosis

Women with endometriosis should not have to endure menopausal symptoms on their own. HRT can help women achieve hormonal balance and reduce discomfort during this phase of life. A tailored treatment plan that factors in a patient’s age, menopausal status, symptom severity, and medical history is especially important for women with endometriosis, whose treatment approach may vary. 

Women diagnosed with endometriosis who are interested in HRT should be medically evaluated to determine if they are eligible for treatment. For women who have had a hysterectomy and/or bilateral oophorectomy, the extent of endometriotic tissue growth should be assessed during surgery before starting HRT.⁽⁹⁾ Women and their healthcare providers should continue monitoring endometriosis and adjust HRT treatment as needed.