Medications

Treatment with medicines does not cure endometriosis. Medicines are also generally not recommended if infertility from endometriosis is your main problem. But anti-inflammatory (NSAID) therapy can reduce pain and bleeding. Hormone therapy with birth control hormones, a gonadotropin-releasing hormone agonist (GnRH-a), progestin, or danazol can shrink endometriosis growths and reduce pain.

Birth control hormones and NSAID therapy are usually recommended first. Unlike other hormone therapies, they are least likely to cause serious side effects and can be a long-term treatment option.⁴

Medication Choices

• Anti-inflammatories (NSAIDs) reduce pain, inflammation, and bleeding from endometrial tissue.
• Birth control hormones (patch, pills, or ring) create hormone levels in the body that are similar to pregnancy. This stops monthly ovulation and the growing, shedding, and bleeding that makes endometriosis painful. Birth control hormones improve endometriosis pain for most women.⁷ And birth control hormones are the hormone therapy that is least likely to cause bad side effects. For this reason, many women can use them for years. Other hormone therapies can only be used for several months to 2 years. For more general information on birth control hormones, see Birth control pill, patch, or ring.
• Gonadotropin-releasing hormone agonist (GnRH-a) therapy lowers estrogen, triggering a menopause-like state. This shrinks implants and reduces pain for most women. This relief usually lasts for 6 to 12 months after ending GnRH-a therapy.⁸
• Progestin (pills or Depo-Provera shot) creates progestin levels in the body that are similar to pregnancy. This stops ovulation and lowers estrogen, shrinking endometriosis growths and reducing pain for most women.
• Danazol therapy lowers estrogen levels and raises androgen levels, triggering a menopause-like state. This shrinks endometriosis implants and reduces pain for most women. This relief usually lasts for 6 to 12 months after treatment. But danazol side effects can be significant.
• Aromatase inhibitors stop estrogen production. In small studies, aromatase inhibitors have been shown to reduce pain and the chance of endometriosis growths coming back. Aromatase inhibitors may help women with endometriosis who have not had relief with hormonal treatments. Aromatase inhibitors are used in combination with a hormonal treatment (such as birth control hormones or progestin). Long-term use of aromatase inhibitors may cause bone loss. More research needs to be done before it is known how well this treatment works and what the side effects are.¹³

Should I use hormone therapy to treat endometriosis?

Treatment with medicine does not restore fertility. In fact, hormone therapy prevents or endangers pregnancy. NSAIDs have been linked to increased miscarriage risk, especially at the time of conception and when an NSAID is used for longer than a week.¹²

What To Think About

Ovarian cancer risk is higher in women who have endometriosis.² Using birth control hormones for 5 or more years lowers this risk.⁴ Danazol may increase ovarian cancer risk.⁵

All hormone therapies for endometriosis can cause side effects and pose certain health risks. Some cause especially unpleasant side effects. Before starting a medicine or hormone therapy, review its possible side effects. If they sound less difficult than your endometriosis symptoms, discuss the therapy with your health professional.

GnRH-a, high-dose progestin, and aromatase inhibitors cause bone thinning. The GnRH-a effect is managed by also taking a small amount of hormone or other medicine (add-back therapy) and limiting GnRH-a use to 6 months. The progestin effect is slower. It takes 2 years of use to cause bone-thinning problems.¹⁴ After therapy, the bones regain most or all of their density.

Some studies of women with severe endometriosis who are infertile have found that 6 months of GnRH-a therapy before in vitro fertilization improves the chances of conceiving a successful pregnancy.¹⁵

Some studies suggest that using hormone therapy after surgery can make the pain-free period longer by preventing growth of new or returning endometriosis.⁷

Pain recurrence after hormone therapy

After treatment with any hormone therapy, endometriosis pain may return:¹

• Per year, up to 20% of all women treated will have pain that returns after hormone treatment.
• About 37% of women who use hormone therapy for mild endometriosis have pain 5 years later.
• About 74% of women who use hormone therapy for severe endometriosis have pain 5 years later.

If you use a GnRH-a or progestin to treat returning pain, it is likely that you will have pain relief much like you did the first time.¹