Endometriosis is a condition in which cells from the endometrium - or uterine lining - grow outside the uterus and adhere to other structures in the pelvis, most commonly the ovaries, bowel, fallopian tubes or bladder. It is a benign (noncancerous) condition. According to the American College of Obstetricians and Gynecologists (ACOG), endometriosis is a common condition affecting 10 to 15 percent of reproductive-age women. It rarely causes symptoms following natural or surgical menopause.

The most common symptoms of endometriosis are painful menstrual periods or non-cyclic pelvic pain. However, the type and intensity of symptoms vary greatly among women with endometriosis. Symptoms may be completely disabling or mild. Sometimes the condition is present and causes few to no symptoms. Chronic pelvic pain is common in women with endometriosis. Other symptoms may include:

  • diarrhea and painful bowel movements especially during menstruation
  • painful intercourse
  • abdominal tenderness
  • severe cramping

Endometriosis with scarring that distorts the anatomy of the pelvic organs may impair fertility. When there is no distortion of the pelvic organs or blockage of the fallopian tubes, endometriosis is less likely to impair fertility.

Researchers are not clear what causes endometriosis. Many theories exist. One theory suggests that retrograde menstruation — or "reverse menstruation" may be the predominant cause. Instead of flowing out of the cervix (opening of the uterus to the vagina) each month some menstrual blood containing endometrial tissue is pushed backward and out of your uterus through the fallopian tubes into the pelvic cavity.

Copyright 2003 National Women's Health Resource Center Inc. (NWHRC)