Everything you need to know about ovarian cysts


The lowdown on ovarian cyst causes, symptoms, treatment and removal.

By Dr Juliet McGrattan (MBChB)

Concerned about ovarian cysts? An ovarian cyst is a fluid-filled sac that commonly forms on the ovaries. Most ovarian cysts are harmless and resolve on their own, but sometimes they can become large, cause pain and may even be cancerous.

How do you know if you have a cyst that needs treatment and when should you see a doctor? And can having an ovarian cyst affect your fertility and what happens if you have a cyst while you are pregnant?

Dr Juliet McGrattan looks at everything from cyst symptoms to removal in our complete guide to ovarian cysts:

What is an ovarian cyst?

A cyst is simply a small sack or pocket that is filled with something, usually fluid, air or a thick or semi-solid substance. Cysts can develop anywhere in the body, most commonly on the skin. Ovarian cysts are usually filled with fluid and they can grow within the ovary itself or attached to the outside.

Types of ovarian cysts

There are two types of ovarian cysts:

  1. Functional cysts: these are the most common type of cyst and they form as a result of the normal menstrual cycle. A follicle that usually ruptures during ovulation might just carry on growing either before (simple cyst) or after (luteal cyst) it has released its egg. Functional cysts don’t last long, they usually resolve quickly and are harmless.
  2. Pathological cysts: these form when cells multiply and overgrow and form tumours. These can be malignant (cancerous) but are usually benign (non-cancerous) and are rarer than functional cysts. 95 per cent of pathological cysts are benign and there are many different types including dermoid cysts and cystadenomas.

Dermoid cysts

Also called teratomas, dermoid cysts are congenital (present from birth) and may run in families. They aren’t linked to the menstrual cycle and form from embryonic cells that have the potential to develop into any type of cell. This means dermoid cysts sometimes contain hair, teeth, bone or skin.

Dermoid cysts can grow large, sometimes up to 15cm in diameter. They are most commonly found in women under 40 and are often discovered by chance during a scan or examination for another condition.


These form from the cells of the outer part of the ovary and are more common in women over 40. The first type is called a serous cystadenoma which usually stays quite small whereas the second type, a mucinous cystadenoma can grow very large, up to 30 cm in diameter. Both types can twist, rupture and cause symptoms by pressing on the structures around them such as the bladder or bowel.


Endometriosis is a condition where tissue from the endometrium (lining of the womb) grows at other locations in the body such as the bowel, fallopian tubes or on the ovary where it can develop into a cyst. Endometriomas are sometimes called ‘chocolate cysts’ because they’re filled with old, brown blood.

Polycystic ovaries

Sometimes multiple cysts can develop on an ovary and if there are more than 12 it is called a polycystic ovary. Polycystic ovary syndrome (PCOS) is a condition where multiple cysts develop on the ovaries and there other symptoms and signs due to an abnormal balance of sex hormones including oestrogen and testosterone.

PCOS signs include acne, weight gain, body and facial hair growth, lack of periods (amenorrhoea) and difficulty conceiving. These cysts however are usually much smaller than functional or pathological cysts and should be considered as a separate condition.

Who is at risk of ovarian cysts?

Any woman can develop cysts on her ovaries. Functional cysts are linked to the menstrual cycle so are more common in women who are having periods. Pathological cysts, including cancerous cysts are more likely in women who have gone through the menopause.

Cysts are more prone to develop at times of hormonal change such as during pregnancy.

Cysts are more prone to develop at times of hormonal change such as during pregnancy or while taking a progesterone based contraceptive, for example, the progesterone-only pill, contraceptive implant or an intrauterine system (IUS). They are also more common in women who are receiving hormones as part of fertility treatment or taking hormonal therapy for breast cancer.

Women who have polycystic ovary syndrome or endometriosis have an increased risk of developing ovarian cysts.

Net Doctor


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