Fact Sheet


  • Editors
  • JoAnn Pinkerton, MD
    Dale W. Stovall, MD
    Hugh S. Taylor, MD

What is endometriosis?

Endometriosis is a condition in which the tissue usually found inside the uterus grows in places where it shouldn’t.  Normally, the uterus is lined with tissue (called the endometrium) that grows and thickens every month to prepare for pregnancy.  Hormones made by the ovaries control this monthly process.  If pregnancy doesn’t occur, the blood and tissue break down and leave the body as menstrual flow (a period).

Did you know?

About 30 to 40 percent of women with endometriosis have trouble getting pregnant.  

However, problems arise if the endometrial tissue grows in areas outside of the uterus, such as on the ovaries; fallopian tubes; the bladder, bowels, or rectum; or on tissue lining the pelvis.  Hormones tell the displaced tissue (called implants) to break down each month.  But the blood and tissue have no way to leave the body.  Scar tissue and cysts (sacs that are often filled with old blood) can form.  Large cysts sometimes break open.  Endometriosis can cause chronic pain and infertility.

What causes endometriosis?

The exact cause is unknown.  One possible cause is a process called retrograde menstruation.  It occurs when menstrual blood flows back through the fallopian tubes into the pelvis instead of out of the body.  Then tissue from the uterus stays in the pelvis and grows.  Another possible cause is inheriting a gene that increases the risk for endometriosis. 


Women are more likely to have endometriosis if they have

Women who have never given birth are also at higher risk.

What are the symptoms of endometriosis?

Infertility is sometimes the first symptom of endometriosis.  However, treatment can help these women become pregnant. 

Some women have no symptoms at all. For other women, in addition to infertility, symptoms include

The amount of pain a woman feels is not related to the extent of her endometriosis.  Still, severe or frequent pain can interfere with daily activities.  Women coping with pain or infertility may feel worried, angry, depressed, or frustrated. 

How is endometriosis diagnosed?

A woman who suspects endometriosis should describe her symptoms to her doctor. Several types of tests help make a diagnosis:

But the only way a doctor can know for certain whether a woman has endometriosis is with a type of surgery called a laparoscopy.  The doctor inserts a lighted viewing device through a small cut in the abdomen.  Then the doctor looks for endometrial implants outside the uterus.  Laparoscopy reveals whether the endometriosis is mild, moderate, or severe. 

What is the treatment for endometriosis?

Endometriosis is treated with medicines, surgery, or both.  Over-the-counter pain relievers help with menstrual cramps and other forms of pain.  Hormone treatments decrease or block the action of ovarian hormones that cause the implants to grow and bleed.  Hormone treatments include

In conservative surgery, the surgeon removes tissue growths and scar tissue.  This type of surgery can relieve pain and help fight infertility.  As a last resort, surgeons may remove the uterus (called a hysterectomy)when endometriosis is severe.  Sometimes the ovaries are also removed.  Pregnancy isn’t possible after a hysterectomy. 

What else can you do to cope with endometriosis?

Some women find that taking warm baths or using a heating pad helps with pain.  Alternative medical treatments, such as acupuncture, have not been proven to help women with endometriosis.  Support groups provide guidance and comfort for some women.

Questions to ask your doctor


MedlinePlus (National Institutes of Health): www.nlm.nih.gov/medlineplus/endometriosis.html

American College of Obstetricians and Gynecologists: www.acog.org/publications/patient_education/bp013.cfm

Healthy Women: www.healthywomen.org/condition/endometriosis

Mayo Clinic: www.mayoclinic.com/health/endometriosis/DS00289

WomensHealth.gov (U.S. Department of Health and Human Services):  http://womenshealth.gov/publications/our-publications/fact-sheet/endometriosis.cfm