Endometriosis is a condition of the female reproductive system which occurs when endometrium, the tissue that usually lines inside the uterus, starts to grow on other parts of the body internally. Endometriosis comes from the combination of endo, which means inside, and metrium, which refers to the uterus, the organ where babies are carried before being born. The most common place for the formation of lesions is the pelvic cavity, which includes on or under the ovaries, on the fallopian tubes, behind the uterus, on the tissues that hold the uterus in place, and on the bowels or bladder.
While pain and infertility are the two main symptoms of endometriosis, the disease manifests itself in other ways as well, including painful bowel movements and digestive or gastrointestinal symptoms similar to a bowel disorder. In addition to the pelvic cavity, endometriosis can affect the bowel in two forms. Superficial bowel endometriosis occurs on the surface of the bowel while deep bowel endometriosis penetrates the bowel wall.