Endometriosis is an often painful disorder in which tissue that normally lines the inside of your uterus — the endometrium — grows outside your uterus (endometrial implant).  Endometriosis most commonly involves your ovaries, bowel or the tissue lining your pelvis.  Rarely, endometrial tissue may spread beyond your pelvic region.

In 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 tissue that binds organs together.

Endometriosis can cause pain — sometimes severe — especially during your period.  Fertility problems also may develop.  Fortunately, effective treatments are available.


Common signs and symptoms of endometriosis may include:

–     Painful periods (dysmenorrhea) – Pelvic pain and cramping may begin before and extend several days into your period and may include 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 your period.

    Excessive bleeding – You may experience occasional heavy periods (menorrhagia) or bleeding between periods (menometrorrhagia).

–     Infertility – Endometriosis is first diagnosed in some women who are seeking treatment for infertility.

–     Other symptoms – You may also experience fatigue, diarrhea, constipation, bloating or nausea, especially during menstrual periods.


Although the exact cause of endometriosis is not certain, several possible explanations include:

–     Retrograde menstruation – This is the most likely explanation for endometriosis.  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.

–     Embryonic cell growth  The cells lining the abdominal and pelvic cavities come from embryonic cells.  When one or more small areas of the abdominal lining turn into endometrial tissue, endometriosis can develop.

–     Surgical scar implantation – After a surgery, such as a hysterectomy or C-section, endometrial cells may attach to a surgical incision.

–     Endometrial cells transport – The blood vessels or tissue fluid (lymphatic) system may transport endometrial cells to other parts of the body.

    Immune system disorder – It’s possible that a problem with the immune system may make the body unable to recognize and destroy endometrial tissue that’s growing outside the uterus.

Risk Factors

Several factors place you at greater risk of developing endometriosis, such as:

–     Never giving birth.

–     One or more relatives (mother, aunt or sister) with endometriosis.

–     Any medical condition that prevents the normal passage of menstrual flow out of the body.

–     History of pelvic infection.

–     Uterine abnormalities.

Endometriosis usually develops several years after the onset of menstruation (menarche).  Signs and symptoms of endometriosis end temporarily with pregnancy and end permanently with menopause, unless you’re taking estrogen.

Tests and Diagnosis

To diagnose endometriosis and other conditions that can cause pelvic pain, your doctor will ask you to describe your symptoms, including the location of your pain and when it occurs.

Tests to check for physical clues of endometriosis include:

–     Pelvic exam – During a pelvic exam, your doctor manually feels (palpates) areas in your pelvis for abnormalities, such as cysts on your reproductive organs or scars behind your uterus.  Often it’s not possible to feel small areas of endometriosis, unless they’ve caused a cyst to form.

–     This test uses high-frequency sound waves to create images of the inside of your body. To capture the images, a device called a transducer is either pressed against your abdominal skin or inserted into your vagina (transvaginal ultrasound).  Both types of ultrasound may be done to get the best view of your reproductive organs.  Ultrasound imaging won’t definitively tell your doctor whether you have endometriosis, but it can identify cysts associated with endometriosis (endometriomas).

–     Medical management is usually tried first.  But to be certain you have endometriosis, your doctor may refer you to a surgeon to look inside your abdomen for signs of endometriosis using a surgical procedure called laparoscopy.  While you’re under general anesthesia, your surgeon makes a tiny incision near your navel and inserts a slender viewing instrument (laparoscope), looking for endometrial tissue outside the uterus.  He or she may take samples of tissue (biopsy).  Laparoscopy can provide information about the location, extent and size of the endometrial implants to help determine the best treatment options.

Treatments and Drugs

Treatment for endometriosis is usually with medications or surgery.  The approach you and your doctor choose will depend on the severity of your signs and symptoms and whether you hope to become pregnant.

Generally, doctors recommend trying conservative treatment approaches first, opting for surgery as a last resort.

Pain Medications

Your doctor may recommend that you take an over-the-counter pain reliever, such as the non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen (Advil, Motrin IB, others) or naproxen (Aleve, others), to help ease painful menstrual cramps.  However, if you find that taking the maximum dose doesn’t provide full relief, you may need to try another approach to manage your signs and symptoms.

Hormone Therapy

Supplemental hormones are sometimes effective in reducing or eliminating the pain of endometriosis.  That’s because the rise and fall of hormones during the menstrual cycle causes endometrial implants to thicken, break down and bleed.  Hormone medication may slow the growth and prevent new implants of endometrial tissue.

However, hormonal therapy isn’t a permanent fix for endometriosis.  It’s possible that you could experience a recurrence of your symptoms after stopping treatment.

Conservative Surgery

If you have endometriosis and are trying to become pregnant, surgery to remove as much endometriosis as possible while preserving your uterus and ovaries (conservative surgery) may increase your chances of success.  If you have severe pain from endometriosis, you may also benefit from surgery — however, endometriosis and pain may return.

Your doctor may do this procedure laparoscopically or through traditional abdominal surgery in more extensive cases.  In laparoscopic surgery, your surgeon inserts a slender viewing instrument (laparoscope) through a small incision near your navel and inserts instruments to remove endometrial tissue through another small incision.

Assisted Reproductive Technologies

Assisted reproductive technologies, such as in vitro fertilization, to help you become pregnant are sometimes preferable to conservative surgery.  Doctors often suggest one of these approaches if conservative surgery is ineffective.


In severe cases of endometriosis, surgery to remove the uterus and cervix (total hysterectomy) as well as both ovaries may be the best treatment.  Hysterectomy alone is not effective — the estrogen your ovaries produce can stimulate any remaining endometriosis and cause pain to persist.  Hysterectomy is typically considered a last resort, especially for women still in their reproductive years.  You can’t get pregnant after a hysterectomy.