What is Endometriosis?

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Endometriosis is a chronic disease that affects around 10% women of childbearing age and is characterised by the growth of endometrial tissue (the inner lining of the uterus) in locations outside the uterus (ectopic) resulting in severe pelvic pain and fertility problems.

Stages of endometriosis

There are three main types of endometriosis:

  • Peritoneal endometriosis. Develops when different sized endometrial implants form on the surface of the peritoneum. The peritoneum is the thin layer of tissue that both lines the internal surface of the abdominal cavity and forms the external surface enclosing the contained organs. 
  • Ovarian endometriosis. This occurs when ectopic endometrial tissue grows in the ovaries, thus forming blood-filled cystic cavities.
  • Deep-infiltrating endometriosis. The ectopic endometrial implants penetrate more than 5 mm beneath the surface of the peritoneum, affecting the underlying organs and structures, such as the intestine, urinary bladder, ureter, pelvic nerves and less frequently the lungs, pleura, soft tissues, etc.
  • Adenomyosis. This is considered a form of endometriosis in which the endometrial tissue affects the uterine muscle tissue.

How common Is Endometriosis?

Endometriosis affects around 10% of women of childbearing age, equivalent to between 1 and 2 million women in Spain and around 176 million women worldwide. It is the most common cause (40%–60% of all cases) of chronic pelvic pain. The maximum incidence occurs in women aged between 35 and 45 years.

Substantiated information by:

Ana Carrión Aliaga
M. Ángeles Martínez Zamora
Meritxell Gracia Quero

Published: 20 February 2018
Updated: 20 February 2018


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