“Ovarian cysts are fluid-filled sacs that develop on or within an ovary,” explains Dr Amit Shah, leading gynaecologist and co-founder of Harley Street clinic Fertility Plus. “They’re quite common and usually form during the ovulation process.”

There are different types of cysts, the most common ones being functional cysts which include:

Follicular cysts: these develop when the follicle, which contains an egg, doesn’t release the egg and continues to grow
Corpus luteum cysts: which form after the egg’s been released and the follicle reseals and fills with fluid

Then you’ve got less common pathological cysts, which form because of abnormal cell growth. You might have read horror health stories of someone who grew a cyst that contained hair, skin or teeth – that’s a pathological cyst which has formed from cells that produce eggs. If you’ve got endometriosis, you might have endometriomas; those happen when womb-like tissue develops outside the uterus. And then you have cystadenomas, which form from cells on the surface of the ovary and can be filled with fluid.

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