Endometriosis is a disorder where the endometrium, the lining of the uterus, begins growing outside the uterus, commonly on nearby structures such as the ovaries, bowel or tissues lining the pelvis. During menstruation, these endometrial implants thicken, break down and bleed, causing irritation and scarring of surrounding tissues, not to mention sometimes severe abdominal pain and infertility. Endometriosis can be treated with pain medications, hormone therapy and/or surgery. If endometriosis is causing infertility, conservative surgical techniques may be used to remove as much of the endometriosis as possible. Assisted reproductive technologies, such as in-vitro fertilization, may also help patients with endometriosis overcome infertility issues.