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Understanding Endometriosis
What is it?

Endometriosis (pronounced en-doh-me-tree-o-sis) is a common condition which happens when tissue -similar to the tissue that makes up the lining of the uterus (endometrium), is found growing and functioning in areas or organs within the body it shouldn’t be. It is most commonly found affecting the lining of the pelvis, the ovaries, the area between the upper vagina and the rectum, the bladder and the bowel.


You can have one or two patches of Endometriosis in one area, or you can have multiple patches of Endometriosis in various parts of the body. These patches can be either on the surface (known as superficial Endometriosis) or deep inside the tissue and surrounding organ(s), or inside the ovaries forming cysts (known as endometriomas).


As it develops, Endometriosis can lead to the formation of fibrous scar tissue, causing organs like the ovaries, fallopian tubes, the uterus, and bowel to stick together. This scar tissue can distort the organs, leading to severe pain and sometimes serious medical problems. In its more severe form, this is known as frozen pelvis disease.


A frozen pelvis happens when the pelvic organs which are normally separate from one another and can move unrestricted, become stuck, fused together and firmly fixed in place. This can affect the function of the organs and is often associated with severe pain and infertility. This happens in a small minority of cases.

Early diagnosis is KEY.

Endometriosis typically affects the pelvis, but it can, in less common cases, appear in distant areas such as the diaphragm (breathing muscle), chest cavity (thorax), and in the wall of the tummy after surgery (caesarean scar). This wide-reaching condition has been documented in nearly every organ in the body, meaning you can come across Endometriosis in any field of medicine.

Is Endometriosis the same as the endometrium?

Under the microscope, Endometriosis contains features that are similar to, but different to the those found in the endometrium, the layer of tissue that makes up the lining of the uterus (womb). There is often an abundance of nerve endings, new blood vessels being formed, and changes in cell type causing scarring surrounding an area of Endometriosis, which is why the tissue is described as ‘similar to’ or ‘endometrial-like’.

Despite these differences, similarly to the endometrium, Endometriosis also responds to the monthly fluctuations in hormones during the menstrual and ovulatory cycle. This is why the pain usually becomes most severe around the time of menstruation and/or ovulation.


However, it doesn’t always take for the rise and fall of hormones to bring on Endometriosis pain. Some people find their symptoms heighten around the time of their periods, whereas others may experience pain and symptoms outside of menstruation or chronic, on-going pain. 

For additional information, resources, and support, please explore our website.


Endometriosis Facts & Figures

Information you can trust


More than 10% of women, girls, and those assigned female at birth are affected.


Endometriosis is the second most common gynaecological condition in the UK.


10% of individuals assigned female at birth AFAB  have Endometriosis. That's an estimated 176 million worldwide - a similar number to those with Diabetes.


It currently takes on average between 7-9 years from the onset of symptoms to achieving a diagnosis in the UK.


Up to 50% of those diagnosed may experience difficulties conceiving. 


The causes are unknown and there is currently no cure. 

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