What is endometriosis?

Endometriosis is a chronic condition in which tissue similar to the uterine lining (endometrium) grows outside the uterus, where it doesn't belong.

With endometriosis, endometrial-like tissue grows on the ovaries, in or on the fallopian tubes, on the peritoneum, around the intestines or bladder, and sometimes (rarely) in other places. The severity of the symptoms does not always correspond to the extent of the endometriosis.

This tissue responds to hormonal fluctuations during the menstrual cycle but cannot be removed like normal menstrual blood. This leads to inflammation, adhesions, scarring, and sometimes cysts (such as chocolate cysts in the ovaries).

Symptoms vary greatly from person to person and range from severe menstrual pain and chronic abdominal or pelvic pain to pain during or after intercourse, painful bowel movements or urination (especially during menstruation), excessive or irregular menstruation, fatigue, and fertility problems.

There is no cure, but symptoms can often be effectively suppressed with hormone therapy (pill, hormonal IUD, progestogens), pain relief, surgery (removal of lesions), or a combination of the above.

Source: https://www.nejm.org/doi/10.1056/NEJMra1810764

Author: Prof. Dr. Dirk Devroey - Latest update: 2025-12-14 - Copyright: Clinifacts 2026