Causes of Endometriosis

No one knows for sure what causes this disease. One theory is that during menstruation some of the menstrual tissue backs up through the fallopian tubes into the abdomen, where it implants and grows. Another theory suggests that endometriosis may be genetic, or runs in families.

Researchers also are looking at the role of the immune system and how it either stimulates or reacts to endometriosis. It may be that a woman's immune system does not remove the menstrual fluid in the pelvic cavity properly, or the chemicals made by areas of endometriosis may irritate or promote growth of more areas. Results from a recent study showed that women who have the disease are more likely than other women to have immune system disorders in which the body attacks its own tissues. This study also found that women with endometriosis are more likely to have chronic fatigue syndrome and to suffer from fibromyalgia syndrome-a disease involving pain in the muscles, tendons, and ligaments. These women also are more likely to have asthma, allergies, and the skin condition eczema. So, researchers feel that further study of the immune system in endometriosis may give important clues to finding the causes of and treatment for the disease.

Other researchers are looking into endometriosis as a disease of the endocrine system, the body's system of glands, hormones, and other secretions, since estrogen appears to promote the growth of the disease. Other research is looking at whether environmental agents, such as exposure to man-made chemicals, cause the disease. More research is trying to understand what, if any, factors affect the course of the disease.

Another important area of research is the search for endometriosis markers. These markers are substances in the body made by or in response to the disease, and can be measured in the blood or urine. If markers are found by a blood or urine test, then a diagnosis for endometriosis could be made without surgery.