Understanding Endometriosis

What is endometriosis?

The endometrium is the lining of the uterus that sheds each month during the menstrual cycle. Endometriosis occurs when tissue similar to the lining of the uterus implants abnormally outside of the uterus in the pelvic cavity to form lesions, cysts, nodules and other growths. These growths have been found on every pelvic organ and surface including ligaments, bladder, ovaries, tubes, uterus, ureters, bowel, and other peritoneal (intra-abdominal) surfaces. More rarely, endometriosis has been found on the lung, diaphragm, nasal cavity and other locations throughout the body. Hormones that trigger the endometrium to bleed each month also stimulate the inappropriately placed tissues.

This can cause pain, internal scarring, formation of adhesions (bands of scar tissue that can connect organs inappropriately), infertility and other medical complications. For each patient with endometriosis, the specific locations of the endometriosis lesions are different, giving rise to a disease that can present uniquely in different patients. Endometriosis is much more than just a disease of the reproductive system—it can affect many systems in the body.

What are the causes of endometriosis?

The cause of endometriosis is unknown. Some theories include: the body’s inability to breakdown back-flow (retrograde) menstruation, congenital origins (genetic causes present at birth), metaplasia (where one cell type turns into a different cell type), circulatory or lymphatic distribution of endometriosis lesions, or a combination of more than one theory. Although heredity plays a role in the development of endometriosis, it can affect individuals of any race from puberty to post-menopause.