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What is endometriosis?

In women with endometriosis womb lining tissue (endometrium) is found outside the womb and can cause pain and discomfort.

Endometriosis is a long-term condition affecting around 2 million women in the UK. It is most commonly diagnosed between the ages of 25 and 40. It is rare after menopause.

Some women will have a mild form of the condition, others will experience extreme pain, heavy periods and will have difficulty becoming pregnant.

Endometriosis occurs when cells like the ones that line the endometrium (womb/uterus lining) are found elsewhere in the body, usually on the pelvic peritoneum, ovaries, bladder and bowel.

What happens with endometriosis?

Each month, at the end of a woman's menstrual cycle, and if pregnancy has not occurred, hormones cause the lining of the womb to break down and bleed. This is then released from the body as a period. With endometriosis cells growing outside the womb will also break apart and bleed. However, the blood will have nowhere to go. This internal bleeding can lead to irritation, inflammation, pain and scar formation.

What causes endometriosis?

Endometriosis is not a result of anything you have or haven't done. There are plenty of theories but no one knows for sure why some women get the condition and others don't.
The most widely accepted theory is that during a period not all the womb lining leaves the body properly. Instead some passes back into the pelvic cavity and attaches to the reproductive organs. This is known as retrograde menstruation. However, this doesn't explain all cases of endometriosis.

What are the symptoms of endometriosis?

The most common symptoms of endometriosis are:

The severity of symptoms depends on where the abnormal endometrial tissue is, not on how much you have. A small amount in one place could be more painful than a larger amount somewhere else in the body.

Who can get endometriosis?

Most women who get endometriosis are diagnosed between the ages of 25 and 40. However, the condition could start at a much younger age when a woman has her first period.

It affects all races equally and is most common in women who have not had children. It occurs more often in women who have fewer than 25 days between periods, or who menstruate for more than 7 days.

It is rare in women after the menopause.

You have a higher risk of developing the condition if your mother or sisters are affected.

Is endometriosis cancer?

Endometriosis is not cancer and does not increase a woman's risk of uterine or other cancers. Endometriosis is also not an infection and is not contagious.

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