Endometriosis refers to the glands of the uterine lining, or endometrium, growing outside the uterus and possibly adhering to other nearby structures, such as the ovaries, bowel, fallopian tubes, or bladder. The breakdown and bleeding of this tissue each month is referred to endometriotic lesions. While no one knows for sure what causes this tissue to grow outside the tissue, we know that endometriosis is stimulated by hormones. Though the condition is non-cancerous, it can result in pelvic pain, not only during the menstrual cycle, but may extend throughout the month. Also, problems with infertility, pain during intercourse, abdominal tenderness, bowel and bladder issues may develop over time.