It is estimated that between 2 and 10% of women within the general population have endometriosis and that up to 50% of infertile women have endometriosis.
Women with endometriosis often have severe symptoms and a significantly reduced quality of life, including pain or discomfort and anxiety including depression.
What is endometriosis?
Endometriosis is a fairly common condition. The tissue that lines the inside of the uterus is called the endometrium, and this is normally shed each month during menstruation.
This tissue is sometimes found in abnormal sites within the body, outside the uterus, usually in the ovaries. When menstruation takes place, these abnormal sites also bleed, but as the blood cannot escape anywhere, it causes pain and a collection of old altered blood (sometimes referred to as a “chocolate cyst”) in the ovary.
Occasionally endometriosis causes no symptoms at all, and the condition is diagnosed only at surgery. More often, however, it causes severe lower abdominal pain, especially during menstruation (which tends to be heavy), and severe discomfort during sexual intercourse.
Women with endometriosis who become pregnant, either naturally or by IVF, often find that their symptoms disappear rapidly. This is because of the natural cessation of menstruation during pregnancy, and also because the high level of progesterone secreted during pregnancy tends to “burn out” the sites of endometriosis.

More information about endometriosis
The ESHRE Special Interest Group Endometriosis and Endometrial Disorders has recently updated its guidelines, which are aimed at clinicians and offer best practice advice on the care of women with suspected endometriosis, including diagnosis of the symptoms and treatment for both relief of painful symptoms and for infertility due to endometriosis.
However, there is also a guide for patients written in plain English which contains a useful explanation of the condition.