Endometriosis is a disorder of the female reproductive system which affects approximately one in 10 women of childbearing age and around two million women in the United Kingdom. The condition can give rise to painful symptoms and even infertility in some sufferers, depending on its severity. Symptoms usually appear in women aged between 25 and 40 years old, however, cases of endometriosis have occurred in teenage girls and even in women approaching menopause.

What Does Endometriosis Do?

When a woman has endometriosis, she has tissue growing in her pelvis and lower abdomen that would usually build up only inside her womb (uterus) during each menstrual cycle. In a normal cycle, this tissue, whose medical name is endometrium, thickens up inside the womb over the course of the month in expectation of a pregnancy. The endometrium prepares to receive an egg released from the ovaries, and, possibly, nurture an embryo should that egg be fertilised. If the egg is not fertilised, a woman will have a period at the end of her cycle, during which the built-up endometrium will be flushed out of her womb in her menstrual blood, leaving room for the endometrium to build up again during the next cycle. In a woman with endometriosis, this tissue grows not only in the womb, but also on, for example, the ovaries, the fallopian tubes, and even in the digestive tract. The blood from the tissue has no way to escape from these places, therefore it continues to build up and can cause pain.


Symptoms of endometriosis include inflammation and persistent pain in the abdomen or pelvic area, painful periods, pain during sexual intercourse (which may occur deep inside and continue to be felt for some time after having sex) and infertility. See our article on symptoms of endometriosis for a more detailed list of signs of the condition.

How Does Endometriosis Cause Infertility?

Having endometriosis can make getting pregnant more difficult. Approximately 40% of endometriosis sufferers struggle to conceive. The build up of tissue outside the womb can cause cysts, scarring and adhesions, as well as blockages, inside the pelvis and abdomen. This can result in the fallopian tubes and ovaries adhering to the lining of the pelvis or to one another. It can also cause these reproductive organs to be incorrectly positioned, which can prevent the transfer of a woman's eggs from her ovaries to her fallopian tubes, meaning that there is no egg available for her partner's sperm to fertilise. Transfer of the egg can also be prevented by clumps of endometriosis blocking the fallopian tubes. It's also possible that the build up of endometrium causes the over-production of prostaglandins, hormones which may interfere with the processes of fertilisation and embryo implantation.


As of yet, endometriosis cannot be definitively cured, only managed, but a range of treatments are available. For mild symptoms, doctors often prescribe anti-inflammatory painkillers, while for more serious cases, hormone treatment to reduce oestrogen levels in the body may be prescribed. Surgery may also be recommended to treat a woman who is struggling to conceive. See our article on treating endometriosis to find out why.