Endometriosis is a disorder where tissue that normally lines the uterus grows outside the uterus, causing abnormal growth of the uterus. Common symptoms include painful menstruation, infertility, irregular or heavy bleeding, pain during sex, and pelvic pain. Diagnosis involves laparoscopy, biopsy, blood tests, MRI or ultrasound. Treatment options include NSAIDs, hormonal drugs like progestins and antiprogestogens, oral contraceptives, and surgery such as laparoscopy or hysterectomy.