Progestin for endometriosis

Examples

Oral (pill)

Generic Name	Brand Name
medroxyprogesterone	Provera
megestrol acetate [50 mg per day]	Megace
norethindrone	Camila, Micronor
norethindrone acetate	Aygestin
norethindrone acetate plus estrogen	Activella, Loestrin
norethindrone plus estrogen	Brevicon, Modicon, Tri-Norinyl

Norethindrone is started at 5 mg and increased at 2.5 mg increments until your periods stop (amenorrhea occurs).

Injection (into a muscle or under the skin)

Generic Name	Brand Name
medroxyprogesterone acetate	Depo-Provera [150 mg], Depo-SubQ Provera 104 [104 mg]

One injection is given every 90 days.

Intrauterine device (IUD) with progestin

Generic Name	Brand Name
levonorgestrel IUD [LNg IUD]	Mirena

Megestrol and Depo-Provera are high-dose progestins.

How It Works

Progestin shrinks endometriosis growths—which are also called implants—and reduces pain for most women.

Progestin is similar to the body's hormone progesterone. Taking progestin creates levels in the body similar to pregnancy. This stops monthly growth of the uterine lining (endometrium) along with endometriosis implants elsewhere in the body. Progestin also reduces estrogen production, which stops ovulation and menstrual periods in most women.

The levonorgestrel (LNg) intrauterine device (IUD) has recently been studied as an endometriosis therapy.¹ It releases a lower daily dose of levonorgestrel, a form of progestin, directly into the uterus. This causes fewer side effects than high-dose progestin pills or injections. In addition to reducing cramping and heavy menstrual bleeding, the LNg IUD is a highly effective method of birth control.

Why It Is Used

Progestin is a second-choice treatment for endometriosis. It is as effective as other hormone therapies. But it is generally reserved for use after birth control pills and/or gonadotropin-releasing hormone agonist (GnRH-a) therapies have not relieved endometriosis pain. This is because, when given by mouth or injection, high-dose progestin may cause bone-thinning and unpleasant side effects.² (Megestrol and Depo-Provera are high-dose progestins. The progestin IUD is not known to have effects on the bone and causes fewer side effects because the progestin dose is lower.)

Progestin injection and the LNg IUD also effectively prevent pregnancy.

How Well It Works

Like all hormone therapies and surgery, progestin does not cure endometriosis.

Progestin improves symptoms of endometriosis, such as pain during periods and pelvic pain.³ When compared with other hormone therapies, it has proven to be equally effective. Generally about 80% to 90% of women gain relief with any particular hormone therapy.¹

The subcutaneous (under the skin) version of medroxyprogesterone acetate (Depo-SubQ Provera 104) works just as well to relieve endometriosis pain as the GnRH-a leuprolide. And it has fewer side effects than leuprolide, especially less bone loss.⁴

Progestin is not used for the treatment of infertility.³

Pain recurrence

After treatment with progestin or any hormone therapy, endometriosis pain can, but does not always, return:¹

• Each 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.

Side Effects

When taken in high doses (such as Depo-Provera or megestrol), progestin can cause:³

• Absence of menstrual bleeding (amenorrhea).
• Abnormal vaginal bleeding, such as irregular spotting to light vaginal bleeding.
• Mood changes or depression.
• Breast tenderness.
• Water retention.
• Weight gain.

The progestin IUD is least likely to cause mood changes, breast tenderness, water retention, and weight gain.

Risks of long-term use

Depo-Provera use for 2 or more years may cause bone loss.⁵ This is thought to rapidly improve after stopping treatment, but it may not be fully reversible after stopping the medicine.¹ Bone loss can lead to osteoporosis in later life, which makes bones weak enough that they are more likely to break.

For teens using progestin, bone thinning is a concern, because the teen years are an important bone-building period. But one study suggests that this bone loss reverses. After 12 months of not using Depo-Provera, teens' bone density seemed to be at expected levels for their age.⁶

Talk to your health professional about taking calcium and vitamin D if you are using progestin.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

If you plan to become pregnant soon after treatment, there is no hormone therapy that will suit your needs. It can take awhile for your menstrual cycle to get back to normal after hormone treatment. After Depo-Provera use in particular, it can take months to be fertile again.

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Author:	Kathe Gallagher, MSW Ralph Poore Monica Rhodes	Last Updated: August 1, 2007
Medical Review:	Kathleen Romito, MD - Family Medicine Deborah A. Penava, BA, MD, FRCSC, MPH - Obstetrics and Gynecology
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