disorder of the female reproductive system (reproductive system, human) characterized by the growth of endometrial tissue (uterine lining) in an abnormal location.

Rather than flowing out of the uterus by way of the vagina (during menstruation), some fragments of the endometrium may leave via the fallopian tubes and move into the pelvic cavity, where they become embedded on other pelvic structures. The most common location of the implants of endometrial tissue are the ovaries (ovary); other areas and organs that are affected are the uterus, the ligaments supporting the pelvic organs, the rectovaginal septum (the membrane dividing the rectum from the vagina), the sigmoid colon (the portion of the large intestine that leads into the rectum), the lower genital tract, and the peritoneum (membrane) lining the pelvis. Rarely, endometrial growths are found in the lungs. Symptoms associated with this disease include (1) progressive, severe pain associated with menstruation or occurring just before it ( dysmenorrhea), (2) dyspareunia (painful intercourse), (3) painful defecation, (4) slight bleeding before menstruation and excessive flow during menstruation, (5) painful urination and blood in the urine, and (6) infertility.

The condition is best diagnosed by laparoscopy, a surgical procedure that allows a physician to examine visually the pelvic organs for endometrial adhesions. For mild endometriosis, pain medications may be the only necessary treatment. Treatment of more severe endometriosis includes surgery and the suppression of ovulation for six to nine months by administration of hormones.