It affects 3-5% of women in the UK, is one of the most common causes of fertility problems and can have a huge impact on a woman's quality of life.
But how much do we really know about it? The quick response: not much.
"There is still a great deal of confusion when it comes to PCOS," says Liz Campbell, director female health charity of Wellbeing of Women, told HuffPost UK Lifestyle.
"Most women in the UK don't know much about their bits, but it's important to be proactive and well-informed about gynaecological problems, such as PCOS, so that one can seek medical health if necessary."
Liz hooked us up with with Miss Agnihotri, a consultant gynaecologist and expert spokesperson for Wellbeing of Women, to find out more.
What is PCOS?
First things first, PCOS is not to be confused with having polycystic ovaries.
While one in five women in the UK have polycystic ovaries, most of them do not the syndrome - meaning they do not have the symptoms associated with PCOS.
According to Wellbeing of Women, PCOS develops when there are a particularly large number of cysts on a woman's ovaries.
These cysts are underdeveloped follicles that contain eggs that haven't developed and often in PCOS these eggs cannot be released.
What are the symptoms?
In many women, the only symptoms are menstrual problems or a failure to conceive.
According to the NHS, common symptoms of PCOS include:
- irregular periods or no periods at all
- difficulty getting pregnant (because of irregular ovulation or failure to ovulate)
- excessive hair growth (hirsutism) - usually on the face, chest, back or buttocks
- weight gain
- thinning hair and hair loss from the head
- oily skin or acne
What are the causes?
The exact cause of PCOS is unknown. But, according to the NHS, it is thought to be related to abnormal hormone levels, including:
- raised levels of testosterone - a hormone often thought of as a male hormone, although all women normally produce small amounts of it
- raised levels of luteinising hormone (LH) - a hormone that stimulates ovulation, but may have an abnormal effect on the ovaries if levels are too high
- low levels of sex hormone binding globulin (SHBG) - a hormone that helps reduce the effect of testosterone
- raised levels of prolactin (only in some women with PCOS) - a hormone that stimulates the breast glands to produce milk in pregnancy
PCOS has also been linked to a resistance to insulin, which can increase testosterone levels. Often this creates a vicious circle as high levels of insulin causes weight gain, and the more overweight you are the more insulin you produce.
There is no cure for PCOS, but the condition can be treated.
"Following a diagnosis of PCOS, each woman should be given general advice emphasising lifestyle change," says Miss Agnihotri. "Simple advice like maintain an ideal BMI and so avoid weight gain as obesity exacerbates symptoms; and the converse achieving ideal BMI is associated with fewer symptoms.
"The lifestyle changes also serve to reduce the risk of developing diabetes and high blood pressure. This is applicable to all age groups."
As far as fertility is concerned, treatment aims to ensure ovulation occurs. There are various treatment options which include simultaneous monitoring as some regimens are associated with a higher incidence of multiple pregnancies (making them high risk pregnancies). The success rates are reassuringly high.
Who does it affect?
PCOS is not age-related, although most women are diagnosed in their teens or early twenties.
It runs in families and can affect any woman irrespective of their background, although some literature suggests that there is a higher prevalence among Asian women.
Advice and awareness
For more information and support visit Wellbeing Of Women or call their helpline on 020 3697 7000.