Topic Overview
By Healthwise

What is endometriosis?
The endometrium is the tissue that lines the uterus. During each menstrual cycle, a new endometrium grows, preparing for a possible pregnancy. If you do not become pregnant during that cycle, the endometrium is shed, which you know as your menstrual period.

Endometriosis is endometrium tissue that grows outside of the uterus. This usually occurs on the ovaries, the fallopian tubes, the outer surface of the uterus, the bowels, or other abdominal organs. Rarely, it can affect other organs and structures in the body.

Endometriosis growths are called “implants.” They grow, bleed, and break down with each menstrual cycle, just like the endometrium does. This can cause pain and can make it difficult to get pregnant. In some cases, scar tissue forms around implants. Scar tissue can also cause pain and problems getting pregnant, and it can interfere with an organ's normal function.

What causes endometriosis?
Experts do not know the exact cause of endometriosis. However, we do know that estrogen "feeds" it. That is why endometriosis only affects women during the years before menopause. During the childbearing years, when the menstrual cycle is regular, women normally have high levels of estrogen. At menopause, menstrual periods stop, and the body's estrogen levels drop.

There are several theories that explain how endometrial cells grow outside of the uterus. The cells may be carried up the fallopian tubes and into the abdomen during menstruation. They may grow from cells that are similar to the endometrium. Or, they may be moved from the uterus by blood or lymph circulation or during a surgery or childbirth.

Experts believe that the body's own defense system (called the immune system) normally kills off any endometrial cells outside of the uterus. However, it appears that in women who have endometriosis, a problem with the immune system helps these cells implant and grow where they don't belong.
Endometriosis also is known to run in families.

What are the symptoms?
While some women with endometriosis never have symptoms, others develop mild, moderate, or severe pain. Depending on where the endometriosis is growing, pain can be in the lower belly or in the rectum or vagina. Pain can happen only before and during the menstrual period or on a constant basis. For some women, pain is most noticeable during sex, a bowel movement, or ovulation. Abnormal vaginal or rectal bleeding can be a sign of endometriosis.

Endometriosis can sometimes make it difficult to get pregnant. Some women never know that they have endometriosis until they see a doctor because they are not able to get pregnant (infertility).

If you have endometriosis, it is likely to be different for you than for another woman who has it. If you have symptoms, they may stay the same, improve, or suddenly get worse. They are likely to improve during pregnancy. For almost all women, endometriosis shrinks away and stops causing symptoms after menopause.

How is endometriosis diagnosed?
Since pelvic pain and infertility have many causes, your health professional will check you for signs of several possible conditions. Diagnosis of endometriosis starts with talking about your history of symptoms and your menstrual periods. You will also have a pelvic exam, which often includes checking both the vagina and rectum.
If your exam, symptoms, and risk factors strongly suggest that you have endometriosis, your health professional may suggest that you try medicine before having more tests. Usually, medicine treatment starts with hormone therapy and/or nonsteroidal anti-inflammatory drug (NSAID) therapy. If your symptoms improve after a few months of treatment, it is even more likely that you have endometriosis.
If you have signs of an endometriosis cyst on an ovary (endometrioma), a test called a transvaginal ultrasound can show the cyst on a computer screen. An MRI or CT scan can also show what is inside your pelvis.

Your doctor may eventually do a laparoscopy. During this surgery, your doctor places a viewing instrument through a small incision in your belly (abdomen) to see how severe your condition is.

How is it treated?
There is no cure for endometriosis. However, you do have options for treating pain and infertility. These include slowing, stopping, or removing endometriosis implants and scar tissue. Your treatment choices depend on whether you plan to get pregnant in the future. You may need to try several different treatments to find one that works best for you.

Pain. For endometriosis that causes only mild symptoms, you may get enough relief with home treatment such using as a heating pad and taking pain medicine that you can buy without a prescription.

When pain medicine is not enough, many women get relief by controlling their menstrual cycles with birth control pills. The advantage of birth control pills is that they are the only hormone therapy that most women can take for years with few or no side effects.

If birth control pills do not help, you may try other hormone therapies that work by lowering the body's estrogen levels. This can cause difficult side effects, however. All hormone therapies relieve endometriosis pain by shrinking endometriosis implants. Overall, they all work well to relieve pain for most women.2 However, pain often returns several months after treatment ends.

Removing implants or scar tissue with surgery relieves pain for most women. However, pain usually returns a year or two after surgery. Taking hormone medicine after surgery may help you stay pain-free longer.

As a last resort for pain treatment, some women have the uterus and ovaries removed (hysterectomy and oophorectomy). Having your ovaries removed drops your estrogen levels and starts early menopause. This relieves symptoms in most cases, but up to 15% of women have pain return.5 Also, removing your uterus and ovaries is a major surgery that has its own risks. It also makes you permanently unable to become pregnant. For more information, see the topic Hysterectomy.
Infertility. Depending on your age (fertility naturally declines after age 35) and how severe your endometriosis is, you have different options. You can improve your chances of pregnancy by having laparoscopic surgery to remove moderate to severe endometriosis, using intrauterine insemination and fertility drugs such as clomiphene (Clomid, for example), and/or having in vitro fertilization (IVF).

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