The lining of the uterus or endometrium may grow elsewhere in the body. When this happens it is called endometriosis. Common sites for endometriosis are ovaries, fallopian tubes, the surface of the uterus, peritoneum (tissue lining the pelvic and abdominal cavities), cul-de-sac (the space behind the uterus), bowels, bladder, and ureters. In response to monthly hormonal changes, the endometrial cells may bleed and cause pain or form cysts. Over time, this can lead to adhesion formation in the pelvic cavity and causes future infertility. Endometriosis occurs more often in women who have never had children. Women with a mother, sister, or daughter who have had endometriosis also are more likely to have it. Endometriosis is found in about three-quarters of the women who have chronic pelvic pain. The most common symptoms are pelvic pain, infertility, and pain during sex. Diagnosis is suspected by history and during a pelvic exam. A definite diagnosis may require a laparoscopy to determine the extent of disease and possibly removing some abnormal tissues and adhesions. Treatment for endometriosis depends on the extent of the disease, your symptoms, and whether you want to have children. It may be treated with medication, surgery, or both. Although treatments may relieve pain and infertility for a time, symptoms may come back after treatment. Endometriosis is a long-term condition. Many women have symptoms that occur off and on until menopause. Keep in mind that there are treatment options. A woman can work with her doctor to decide which treatment is right for her.