The endometrium is the tissue that lines the inside of the uterus. This tissue changes in response to the menstrual cycle hormones by thickening, then shedding itself each month during menstruation. When endometrial tissue grows outside the uterus, ittween the uterus and the rectum). However, endometriosis may develop anywhere in the pelvic cavity, such as on the fallopian tubes, bowels or bladder. Rarely, it can develop outside the abdominal cavity. These endometrial tissue growths, called implants, behave as normal endometrial tissue by thickening and then bleeding during menstruation in response to natural hormonal changes. Since the tissue is not in the uterus, however, the blood may not be able to exit the body. This can cause swelling, pain, blood-filled cysts (pouches), or inflammation and scarring that can lead to adhesions (scarring that has caused internal organs or tissues to become bound together). The exact cause of endometriosis is unknown, but research continues. Among other things, researchers are investigating possible links between endometriosis and genetics, the immune system and hormones. It's known that the growth of endometrial tissue depends on the presence of the hormone estrogen. Endometriosis usually begins during the childbearing years, when estrogen production is high. After menopause, when estrogen production decreases, the endometrial tissue usually shrinks and symptoms disappear on their own. Rarely, endometriosis is reactivated after menopause if hormone replacement therapy (which contains estrogen) is begun. Women who've never been pregnant or have a close relative with endometriosis have a higher risk of developing this condition. Signs/symptomsSome women who have endometriosis have few or no symptoms. Others live with chronic, debilitating pain. Symptoms may include: severe pelvic pain or cramping just before or during menstruation pain during bowel movements low back pain or pain in the thigh or buttock premenstrual spotting with heavy menstrual bleeding pain during or after sex painful or bloody urination infertility DiagnosisYour doctor will do a thorough physical exam, including a pelvic exam, and ask questions about your medical history. Your doctor may also recommend an ultrasound (a test that uses sound waves to create an image of internal body parts) or a magnetic resonance imaging (MRI, an imaging technique based on computer analysis of the body's response to a magnetic field). Even though endometriosis may be suspected from these tests, a laparoscopy must be done to confirm the diagnosis. A laparoscopy is an outpatient surgical procedure done under general anesthesia. First, the doctor makes a small incision in the abdomen. Next, the abdominal cavity is inflated with carbon dioxide to separate the organs and tissues and to give the doctor a better view of the area. Using a laparoscope (a small tube equipped with a very bright light), the doctor looks for endometrial tissue. The laparoscopy will help the doctor evaluate the extent of the condition, as well as determine the location and size of the endometrial implants. In mild cases, the implants may be small and not widespread. In severe cases, there may be extensive endometrial tissue growth with large areas of scar tissue. Interestingly, women who experience more severe pain often have smaller areas of endometriosis, while those who have more extensive cases can have milder symptoms. Note: Researchers are looking for an endometriosis marker, a substance in the blood or urine that would make the diagnosis possible without surgery. TreatmentThere is no cure for endometriosis, but many treatments are available. Medication or surgery can be used to slow or stop the progression of the disease and to help relieve symptoms, improve fertility and prevent complications. Treatment will depend on your age and desire for future children, the severity of the disease and your symptoms. Always discuss treatment risks, benefits and concerns with your doctor. MedicationIf your symptoms are mild, your doctor may suggest an over-the-counter anti-inflammatory pain reliever, such as ibuprofen. Hormone therapy is often used to treat endometriosis as well. By limiting estrogens or increasing androgens, your body can be made to think you're either pregnant or menopausal and ovulation and menstruation will stop. Hormone therapy can also prevent the endometrial tissue from bleeding and allow it to shrink (and sometimes eliminate) endometrial implants. The medications used in hormone therapy include: a combination of estrogen and progestin (such as birth control pills), which regulate the growth of endometrial tissue and make periods lighter and less painful synthetic progestin (brand name Depo-Provera, for example), which reduces or stops menstrual periods and the growth of implants danazol (Danocrine, for example), a hormone that stops menstruation and endometrial symptoms by blocking certain hormones GnRH agonists (Synarel or Lupron, for example), which block the hormones responsible for menstruation, preventing menstruation, and slowing or stopping the growth of implants The success rates for all of these medications are comparable. Your medication of choice may depend on side effects and cost. Keep in mind that symptoms often return after the therapy has been stopped. Researchers are currently studying other methods of treatment, such as using medicated vaginal rings. SurgerySurgery may be an option if medication isn't helpful. Your doctor may be able to remove the endometrial implants, treat adhesions, and correct any abnormalities of the reproductive organs. Sometimes this is done with laparoscopy. In severe cases, abdominal surgery may be necessary. Sometimes the uterus and ovaries are removed. If the condition affects the bowel, a section of the bowel may be removed. Depending on the circumstances, hormone therapy may be suggested before or after surgery. ComplicationsThe hormones used to treat endometriosis may cause various side effects, including nausea, breast tenderness, fluid retention, depression, weight gain, muscle cramps, decreased breast size, acne, oily skin, hot flashes, mood changes, vaginal dryness, insomnia or headaches. Long-term treatment with GnRH agonists (longer than six months) may lead to decreased bone density. To prevent this, an additional hormone may be prescribed with the GnRH agonist. Complications of laparoscopic surgery may include: puncturing an organ infection bleeding perforation of one of the major arteries or veins in the abdomen shoulder or chest pain after surgery due to unabsorbed gas rarely, the need to convert to a traditional open surgery Pregnancy-specific informationEndometriosis symptoms usually subside during pregnancy. Senior-specific informationEndometriosis symptoms usually subside during menopause, as estrogen levels fall. If your doctor suggests hormone replacement therapy, remind him or her of your history of endometriosis -- the symptoms may recur with this type of treatment.