What Causes Endometriosis?
Endometriosis is a condition that hits women during their childbearing years. While no one knows the exact percentage of women plagued by the condition, endometriosis is known to afflict more than one million U.S. women. The reason the exact number of women affected is unknown is due to the fact that the disease may be asymptomatic. Still, experts guess that anywhere from 3% to 18% of women in the United States develop endometriosis.
Endometriosis is one of the major causes of pelvic pain as well as the main reason for performing laparoscopic surgery and hysterectomies within the United States. Though most women receive a diagnosis anywhere between the ages of 25-35 years of age, endometriosis has been found in preteen girls of no more than 11 years of age. On the other hand, it is rare to see evidence of the disease in postmenopausal women.
White women get the condition more often than do African American or Asian women. Endometriosis is also more common in tall, thin women who possess a low body mass index (BMI). Pushing off conception until the later childbearing years is also a known factor in increasing the risk for developing endometriosis.
While the exact cause of the condition is not yet known, theories abound as to why endometriosis develops in a given individual. One theory holds that endometrial tissue deposits are caused by backed up menstrual flow that ends up in the fallopian tubes, pelvis, and abdominal cavity during a woman's period. This is called "retrograde menstruation." Just as the cause of endometriosis is unknown, so it is with retrograde menstruation: no one knows what causes this situation. It is known that many women have this type of menstruation to one degree or another, yet most of them don't develop endometriosis.
Another theory holds that the areas that line the pelvic organs contain primitive cells that can mutate into various tissue types, such as, for instance, endometrial cells. This is called coelomic metaplasia.
Still others posit that surgery can cause endometrial tissue to be transferred to inappropriate locations. This explanation would serve to explain why endometrial tissues sometimes implant in surgical scars after an episiotomy or cesarean section. In an extension of this theory, the transfer of endometrial cells throughout the lymphatic system or via the bloodstream would help explain the rare cases of endometriosis that develop in organs situated far from the pelvis, such as the brain.
A final theory has grown out of research trials that demonstrate an alteration of the immune response in women who suffer from endometriosis. Researchers believe that the condition may impair the body's innate ability to identify and wipe out endometrial tissue that attempts to develop outside of the uterus.