The endometrium is the lining of the uterus, a hollow, muscular organ in a woman?s pelvis. The uterus is where a fetus grows. Genetics may also play a role in whether you get endometriosis. With endometriosis, displaced endometrial tissue continues to act as it normally would ? it thickens, breaks down and bleeds with each menstrual cycle. Because this displaced tissue has no way to exit your body, it becomes trapped. When endometriosis involves the ovaries, cysts called endometriomas may form. Surrounding tissue can become irritated, eventually developing scar tissue and adhesions ? abnormal bands of fibrous tissue that can cause pelvic tissues and organs to stick to each other. Medical professionals don?t know exactly what causes endometriosis. Some experts think that menstrual blood with endometrial cells travels back through the fallopian tubes and passes out into the pelvic cavity where the cells stick to the organs and this is known as retrograde menstruation. Caution: Endometrial thickness cut-off suggested value is 8-11 mm. The risk of carcinoma is ~7% if the endometrium is 11 mm. Testing is highly recommended. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.