Endometriosis

Here's what we do know ...
by National Institute of Health

What is endometriosis?

Endometriosis occurs when tissue like that which lines the inside of uterus grows outside the uterus, usually on the surfaces of organs in the pelvic and abdominal areas, in places that it is not supposed to grow.

The word endometriosis comes from the word "endometrium" - endo means "inside" and metrium (pronounced mee-tree-um) means "mother." Health care providers call the tissue that lines the inside of the uterus (where a mother carries her baby) the endometrium.

Health care providers may call areas of endometriosis by different names, such as implants, lesions, or nodules.

In what places, outside of the uterus, do areas of endometriosis grow?

Most endometriosis is found in the pelvic cavity:

• On or under the ovaries
• Behind the uterus
• On the tissues that hold the uterus in place
• On the bowels or bladder

In extremely rare cases, endometriosis areas can grow in the lungs or other parts of the body.

What are the symptoms of endometriosis?

One of the most common symptoms of endometriosis is pain, mostly in the abdomen, lower back, and pelvic areas. The amount of pain a woman feels is not linked to how much endometriosis she has. Some women have no pain even though their endometriosis is extensive, meaning that the affected areas are large, or that there is scarring. Some women, on the other hand, have severe pain even though they have only a few small areas of endometriosis.

General symptoms of endometriosis can include (but are not limited to):

• Extremely painful (or disabling) menstrual cramps; pain may get worse over time
• Chronic pelvic pain (includes lower back pain and pelvic pain)
• Pain during or after sex
• Intestinal pain
• Painful bowel movements or painful urination during menstrual periods
• Heavy menstrual periods
• Premenstrual spotting or bleeding between periods
• Infertility

In addition, women who are diagnosed with endometriosis may have gastrointestinal symptoms that resemble a bowel disorder, as well as fatigue.

Who gets endometriosis?

Endometriosis can affect any menstruating woman, from the time of her first period to menopause, regardless of whether or not she has children, her race or ethnicity, or her socio-economic status. Endometriosis can sometimes persist after menopause; or hormones taken for menopausal symptoms may cause the symptoms of endometriosis to continue.

Current estimates place the number of women with endometriosis between 2 percent and 10 percent of women of reproductive age. But, it's important to note that these are only estimates, and that such statistics can vary widely.

Does having endometriosis mean I'll be infertile or unable to have children?

bout 30 percent to 40 percent of women with endometriosis are infertile, making it one of the top three causes of female infertility. Some women don't find out that they have endometriosis until they have trouble getting pregnant.

If you have endometriosis and want to get pregnant, your health care provider may suggest that you have unprotected sex for six months to a year before you have any treatment for the endometriosis.

The relationship between endometriosis and infertility is an active area of research. Some studies suggest that the condition may change the uterus so it does not accept an embryo. Other work explores whether endometriosis changes the egg, or whether endometriosis gets in the way of moving a fertilized egg to the uterus.

What causes endometriosis?

We don't know the exact cause of endometriosis. Right now, a number of theories try to explain the disease.

Endometriosis may result from something called "retrograde menstrual flow," in which some of the tissue that a woman sheds during her period flows into her pelvis. While most women who get their periods have some retrograde menstrual flow, not all of these women have endometriosis. Researchers are trying to uncover what other factors might cause the tissue to grow in some women, but not in others.

Another theory about the cause of endometriosis involves genes. This disease could be inherited, or it could result from genetic errors, making some women more likely than others to develop the condition. If researchers can find a specific gene or genes related to endometriosis in some women, genetic testing might allow health care providers to detect endometriosis much earlier, or even prevent it from happening at all.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.