Possible Causes of Endometriosis

The exact causes of endometriosis are unknown. There are several theories under current consideration including:

• Retrograde Menstruation: Endometrial cells back up from the uterus through the fallopian tubes, implant in the abdomen, and grow. This migration process occurs in all women, though an immune or hormonal problem may allow the tissue to grow in the women who develop endometriosis. This theory does not explain why women who undergo tubal ligation or hysterectomy can still experience symptoms of endometriosis.
• Environmental: There may also be a link between exposure to chemicals or allergens and endometriosis. However, there is no conclusive evidence.
• Immunological: Changes have been observed in women with endometriosis. According to this theory, an abnormality in the immune system allows the endometrial cells that are shed normally to attach elsewhere and grow. It is uncertain whether the immunological changes are responsible for the endometriosis or the result of the inflammation caused by the disease.
• Genetic: Endometriosis tends to run in families, though the mode of inheritance remains unknown. Women with an affected mother or sister are more likely to have severe endometriosis than those without affected relatives.