Hormone Therapy

Reviewed by: HU Medical Review Board | Last reviewed: March 2023

Hormone therapy is often used to manage the symptoms of endometriosis. This includes a large group of drugs that change hormone levels in the body. Different drugs work on different hormones.

How does hormone therapy work?

Many hormone therapies prevent ovulation. Ovulation is when an egg is released from the ovary into the fallopian tube. Ovulation may lead to a spike in hormones like estrogen and progesterone. High levels of estrogen and progestin are often linked to the growth, thickening, and break down of endometriosis lesions.1,2

By preventing ovulation, these hormones are stabilized. In theory, this shrinks endometriosis lesions and this reduces pain.

What are the active ingredients of hormone therapy?

The active ingredients of hormone therapy vary by type of prescription and brand.

Examples of hormone therapy

Hormone therapies include:1-8

Combination birth control

Combination birth control contains man-made estrogen and progesterone. Both of these hormones affect how the reproductive system works by preventing the ovaries from working. This may reduce the growth of endometriosis lesions, which may lessen pain.

This group of prescriptions includes:1,2

  • Birth control pills
  • Vaginal ring (NuvaRing)
  • Skin patch (Ortho Evra, Xulane)

These products are also used to prevent pregnancy, and reduce menstrual migraines, acne, and more.1,2

Progestin-only birth control

Progestin is a man-made form of the hormone progesterone. Progestin-only birth control may be taken by people who cannot take estrogen. Progestin is given by pill, injection, or intrauterine device (IUD). These prescriptions prevent the ovaries from working. This reduces menstrual flow and limits growth of the uterus lining. This reduces the size of endometriosis lesions, which may help reduce pain.1-3

Types of progestin-only treatments include:1-3

  • Progestin-only birth control pills
  • IUD (Mirena)
  • Birth control shot (Depo-Provera)

Gn-RH agonists and antagonists

Gonadotropin-releasing hormone agonists and antagonists (Gn-RH agonists and Gn-RH antagonists) reduce estrogen and other hormone levels to a menopause-like state. This may lead to less endometriosis pain. It is taken as a pill, nasal spray, or injection. These prescriptions generally cannot be taken long-term. Most doctors recommend Gn-RH agonists be taken for only 6 months at a time. Gn-RH antagonists have fewer side effects. These are relatively new drugs used for endometriosis and less commonly prescribed.2,4,7

Danocrine (danazol)

Danocrine (danazol) is another drug used to treat endometriosis pain. It is a man-made steroid that has a complex action on hormones. Ultimately, it stops the ovaries from working and decreases estrogen. This decrease in estrogen can shrink endometriosis lesions. It may also prevent these from thickening and breaking down, which decreases pain.2

What are the possible side effects of hormone therapy?

Side effects can vary depending on the specific drug you are taking.

Combination birth control causes monthly periods to become lighter, shorter, or more regular. Other side effects include:2

  • Weight gain
  • Bloating
  • Increased risk of developing blood clots, certain cancers, and bleeding issues

Progestin-only birth control causes monthly periods to become irregular or stop. Other side effects include:2

  • Weight gain
  • Depression

Progestin-only birth control may also increase the risk of developing:2

  • Ovarian cysts
  • Certain cancers
  • Liver issues
  • Ectopic pregnancy (when a fertilized egg implants outside the uterus)

Because Gn-RH agonists and antagonists cause the body to mimic menopause, the side effects may include:2

  • Headaches
  • Nausea
  • Sleep problems
  • Hot flashes
  • Fatigue
  • Vaginal dryness
  • Joint and muscle stiffness
  • Less interest in sex
  • Depression
  • Bone density loss

Long-term use of Gn-RH agonists may increase the risk of high cholesterol, heart disease, and osteoporosis.2,7

Danocrine causes monthly periods to stop or happen occasionally. Other side effects include:2,8

  • Oily skin
  • Weight gain
  • Muscle cramps
  • Smaller or sore breasts
  • Headaches, dizziness
  • Hot flashes
  • Deepening of the voice

These are not all the possible side effects of these drugs. Talk to your doctor about what to expect or if you are concerned about any changes while using hormone therapy.

Things to know about hormone therapy

Before beginning treatment for endometriosis, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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