Patient Education Materials

Women’s Health


Endometriosis (EN-doh-me-tree-OH-sis) is a disease in which endometrial tissue, normally found only in the uterus, is present in other locations in the body.

The endometrium is the lining of the uterus, which is shed during menstruation. When it grows outside the uterus, it can cause patches or cysts (lesions) to form. The most common locations of these lesions are the fallopian tubes, ovaries, bladder, intestines, rectum, and pelvic cavity. In rare cases, lesions may be found in other areas of the body. Endometriosis occurs most often in women ages 25 to 45 who have never been pregnant.

The menstrual cycle and endometriosis

Each month, the ovaries secrete 2 hormones, estrogen (ESS-tre-jen) and progesterone (pro-JESS-tuh-rohn). These hormones feed the endometrium as it grows and thickens in preparation for a fertilized egg. When fertilization does not occur, the endometrium is shed as menstrual flow (this is your period).

Just like the normal endometrium, the endometrial tissue outside the uterus also is affected by the hormones, and it attempts to shed in the same manner. Since the lesions caused by endometriosis are deep inside the body, they bleed into surrounding tissue. The body defends itself from this bleeding by “sealing off” the endometriosis site. This causes scar tissue or cysts to form.

Causes of endometriosis

The exact cause of endometriosis is not known. Some scientists believe that some of the normal endometrial tissue moves from the uterus backwards through the fallopian tubes and into the pelvis and/or abdomen. From these sites, the lesions may spread to other areas of the body by way of the blood.

Symptoms of endometriosis

The symptoms of endometriosis are:

  • Pain — The most common symptom of endometriosis is pain with menstruation. It usually begins 1 to 10 days before menstruation, and may continue for 1 to 2 days after menstruation stops.

The severity is often linked to where the lesions are and what organs they are affecting. Endometriosis may cause pain in the entire lower abdominal area or on 1 or both sides of the lower abdomen. It may even move to both thighs. It can occur during sex (intercourse) and be felt in the rectum when bearing down during a bowel movement.

  • Menstrual irregularities — Another common symptom of endometriosis is an abnormal menstrual cycle. Menstrual flow may be heavier, last longer, and/or increase in frequency. Premenstrual staining or spotting may occur 2 to 3 days before the onset of menstruation. Endometriosis lesions in or around the colon may cause rectal bleeding before, during, or after menstruation.
  • Infertility — For some women, infertility may be the first or only symptom of endometriosis. If endometriosis has spread widely, it may cause infertility by blocking the path of the egg to the fallopian tube or by surrounding the ovary so the egg cannot free itself.

About 30 percent of women who have never been pregnant have endometriosis, and about 5 percent of fertile women have endometriosis. The pregnancy rate among women with known endometriosis is less than the pregnancy rate in the general population.

Testing for endometriosis

Endometriosis is usually found during pelvic exams given by your doctor. Endometrial lesions may be present in locations in the pelvis or abdomen. To find the lesions, a doctor will usually perform a procedure called a laparoscopy (lap-a-ROSS-kuh-pee).

During a laparoscopy, the doctor makes a small cut (incision) into the abdomen, just below the belly button (navel). A small telescope with a light on the end (laparoscope) is inserted through this small incision. The laparoscope allows the doctor to view the reproductive organs and any endometrial lesions that are present.

A second small incision may be made in the abdomen to remove tissue samples. These samples will be sent to a laboratory to confirm they are endometriosis.

Treatment of endometriosis

Treatment of endometriosis depends on the location of lesions, severity of symptoms, age of the woman, and desire to preserve her ability to have children. Generally the treatment options include:

  • Surgical treatment
  • Hormonal treatment
  • A combination of surgical and hormonal treatment

Decisions about treatment are made jointly by a woman and her doctor.

A final word

Today, endometriosis can be treated more successfully than ever before. Since the disease affects every woman differently, you should consider all of your options. Review them with your doctor and with those who are close to you.

Your doctor can best answer your specific questions. He or she can also give you a detailed explanation of treatment options and guide you in your decisions.