The name comes from the word "endometrium", which is the tissue that lines the uterus. During a woman's regular menstrual cycle, this tissue builds up and is shed if she does not become pregnant. Women with endometriosis develop tissue that looks and acts like endometrial tissue outside the uterus, usually on other reproductive organs inside the pelvis or in the abdominal cavity. Each month, this misplaced tissue responds to the hormonal changes of the menstrual cycle by building up and breaking down just as the endometrium does, resulting in internal bleeding.

Unlike menstrual fluid from the uterus which is shed by the body, blood from the misplaced tissue has nowhere to go, resulting in the tissues surrounding the endometriosis becoming inflamed or swollen. This process can produce scar tissue around the area which may develop into lesions or growths. In some cases, particularly when an ovary is involved, the blood can become embedded in the tissue where it is located, forming blood blisters that may become surrounded by a fibrous cyst.
Endometriosis is a common gynecological condition, particularly among women of childbearing age, affecting an estimated 10 to 20 percent of American women (or about 5 million women) in this age group. Endometriosis can be a debilitating disease for some women who experience ongoing pain, while others may be asymptomatic. It is also a factor in infertility, with about 25 percent of women with endometriosis experiencing difficulty conceiving a child.
A staging system has been developed by the American Society of Reproductive Medicine (formerly the American Fertility Society). The stages are classified according to the following:
| Stage | Level of Severity |
| Stage I | minimal |
| Stage II | mild |
| Stage III | moderate |
| Stage IV | severe |
The stage of endometriosis is based on the location, amount, depth, and size of the endometrial implants. Specific criteria include:
The stage of the endometriosis does not necessarily reflect the level of pain experienced, risk of infertility, or symptoms present. For example, it is possible for a woman in Stage I to be in tremendous pain, while a woman in Stage IV may be asymptomatic. In addition, women who receive treatment during the first two stages of the disease have the greatest chance of regaining their ability to become pregnant following treatment.
Endometriosis is most often found in the ovaries, but can also be found in other places, including:
Occasionally, the implants are found in other places, such as:
The following are the most common symptoms for endometriosis, however, each individual may experience symptoms differently. Symptoms of endometriosis may include:
It is important to note that the amount of pain a woman experiences is not necessarily related to the severity of the disease - some women with severe endometriosis may experience no pain, while others with a milder form of the disease may have severe pain or other symptoms
Endometriosis is considered one of the three major causes of female infertility. It has been estimated that between 25 and 50 percent of all infertile women have endometriosis. In mild to moderate cases, the infertility may be just temporary with surgery to remove adhesions, cysts, and scar tissue restoring fertility. In other cases (a very small percentage), women may remain infertile. Physicians are still not clear how endometriosis affects fertility.
The causes of endometriosis are still unknown, although many theories abound. One theory suggests that during menstruation some of the tissue backs up through the fallopian tubes into the abdomen, a sort of "reverse menstruation", where it attaches and grows. Another theory states that certain families may have predisposing genetic factors to the disease. Current research is also looking at the role of the immune system in activating cells that may secrete factors which stimulate endometriosis
While any woman may develop endometriosis, the following women seem to be at an increased risk for the disease:
For many women, simply having a diagnosis of endometriosis brings relief. Diagnosis begins with a gynecologist evaluating a patient's medical history and a complete physical examination including a pelvic exam. A diagnosis of endometriosis can only be certain when the physician performs a laparoscopy (a minor surgical procedure in which a laparoscope, a thin tube with a lens and a light, is inserted into an incision in the abdominal wall. Using the laparoscope to see into the pelvic area, the physician can often determine the locations, extent, and size of the endometrial growths.).
Other examinations which may be used in the diagnosis of endometriosis include:
Specific treatment for endometriosis will be determined by your physician based on:
If symptoms are mild, physicians generally agree that no further treatment, other than pain medication, is necessary.
In general, treatment for endometriosis may include:
Simple tips that can help ease the pain of endometriosis include:
Surgical techniques which may be used to treat endometriosis include:
Sometimes a combination of therapies are used, such as conservative surgery (laparoscopy or laparotomy), along with hormone therapy.
Some women also benefit from alternative treatments used in conjunction with other medical and surgical therapies for the treatment of endometriosis. These include:
It is important to discuss any/all of these treatments thoroughly with your physician, as some may conflict with the effectiveness of others.