Endometriosis is a medical condition that occurs when the lining of the uterus, called the endometrium, grows in other places, such as the fallopian tubes, ovaries or along the pelvis. When that lining breaks down, like the regular lining in the uterus that produces the menstruation, it has nowhere to go. This causes cysts, heavy periods, severe cramps and even infertility.
The primary symptom of endometriosis is pelvic pain, often associated with menstrual periods. Although many experience cramping during their menstrual periods, those with endometriosis typically describe menstrual pain that's far worse than usual. Pain also may increase over time.
Common signs and symptoms of endometriosis include:
•Painful periods (dysmenorrhea). Pelvic pain and cramping may begin before and extend several days into a menstrual period. You may also have lower back and abdominal pain.
•Pain with intercourse. Pain during or after sex is common with endometriosis.
•Pain with bowel movements or urination. You're most likely to experience these symptoms during a menstrual period.
•Excessive bleeding. You may experience occasional heavy menstrual periods or bleeding between periods (intermenstrual bleeding).
•Infertility. Sometimes, endometriosis is first diagnosed in those seeking treatment for infertility.
•Other signs and symptoms. You may experience fatigue, diarrhea, constipation, bloating or nausea, especially during menstrual periods.
Although the exact cause of endometriosis is not certain, possible explanations include:
•Retrograde menstruation. In retrograde menstruation, menstrual blood containing endometrial cells flows back through the fallopian tubes and into the pelvic cavity instead of out of the body. These displaced endometrial cells stick to the pelvic walls and surfaces of pelvic organs, where they grow and continue to thicken and bleed over the course of each menstrual cycle.
•Transformation of peritoneal cells. In what's known as the "induction theory," experts propose that hormones or immune factors promote transformation of peritoneal cells — cells that line the inner side of your abdomen — into endometrial cells.
•Embryonic cell transformation. Hormones such as estrogen may transform embryonic cells — cells in the earliest stages of development — into endometrial cell implants during puberty.
•Surgical scar implantation. After a surgery, such as a hysterectomy or C-section, endometrial cells may attach to a surgical incision.
•Endometrial cell transport. The blood vessels or tissue fluid (lymphatic) system may transport endometrial cells to other parts of the body.
•Immune system disorder. A problem with the immune system may make the body unable to recognize and destroy endometrial tissue that's growing outside the uterus.
Treatment for endometriosis usually involves medication or surgery. The approach you and your doctor choose will depend on how severe your signs and symptoms are and whether you hope to become pregnant. Your doctor will typically recommend trying conservative treatment approaches first, opting for surgery if initial treatment fails.