Endometriosis Patient Information Fact Sheet

What is endometriosis?
The medical term for the lining of the womb (uterus) is the endometrium. The cells that make up the endometrium are responsive to hormonal changes that occur throughout the menstrual cycle. These changes cause the lining of the womb to thicken in preparation for a fertilized egg. If fertilization does not occur, the lining is then shed in the form of a monthly period. In women with endometriosis, some of the specialized cells that make up the endometrium are also found outside the womb. The cells outside the womb react to hormonal changes in the same way as those inside the womb. However, when the cells outside the womb break down and bleed they remain inside the body, where they can cause considerable pain and discomfort. They can also cause the formation of scar tissue.

The severity of endometriosis varies depending on where the extra cells occur. The cells can grow anywhere in the body, but are usually found within the pelvis; for example, within the fallopian tubes, ovaries, bladder, or bowel. It is estimated that endometriosis affects at least 6.3 million women and girls in the U.S.

What causes endometriosis?
It is not known what causes the growth of the extra endometrial cells, and currently there is no cure for the condition. However, there are a number of treatments available that can help manage the symptoms.

What are the symptoms of endometriosis?
Severe pain may be experienced during periods as a result of bleeding outside the womb. Pain may also be experienced at the time of ovulation or during sexual intercourse. Periods may be heavy (sometimes with clots) or prolonged. Endometriosis may cause the fallopian tubes to become blocked. This can prevent the passage of eggs from the ovaries and lead to fertility problems. Endometriosis is often diagnosed during investigations into infertility.

What tests confirm a diagnosis of endometriosis?
Endometriosis is usually diagnosed using a procedure called a laparoscopy. This is a minor operation that may be carried out as outpatient surgery. A laparoscope, a small fiber-optic tube that transmits images to a video monitor, is passed into the pelvis via a tiny incision at the navel. This enables the doctor to view inside the pelvis and look for the presence of the extra cells.

How is endometriosis treated?
There are two main forms of treatment available: surgery and drug therapy. The most appropriate method will be chosen according to the severity and location of the endometriosis.

Surgery can be performed to remove areas of endometriosis, and parts of the reproductive organs if they are badly affected. Decisions about the extent of the surgery, however, will depend on whether a woman wishes to conceive in the future. Surgery may also help if the endometriosis is causing fertility problems.

The most common form of treatment is drug therapy. There are a number of drugs that can be prescribed according to each woman's particular circumstances. If one drug is not well tolerated, another can be prescribed. A group of drugs called GnRH analogs may be used to treat endometriosis. These drugs work by decreasing the activity of the ovaries, leading to inhibition of endometrial growth. Drugs in this group include goserelin (Zoladex), leuprolide (Lupron Depot), and nafarelin (Synarel). GnRH analogues can cause side effects similar to the symptoms experienced during the menopause. They are often prescribed to reduce the number and size of endometrial lesions and may also be given to thin the endometrium prior to surgery. It is important that pregnancy does not occur during treatment; therefore, women must use a barrier method of contraception during treatment. Progestogens such as medroxyprogesterone (Provera) and norethindrone (Aygestin) suppress ovulation, but normal ovulatory cycles can return two months after treatment is stopped. They are therefore useful for women who wish to conceive after treatment. The combined oral contraceptive pill may also help in decreasing the severity of endometriosis. Pain medication such as ibuprofen (Advil, Motrin) or naproxen (Aleve) may also be used.

Further information
Endometriosis Association: www.endometriosisassn.org
Pubmed Health: www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001913/

Last reviewed: May 2013