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Polycystic Ovary Syndrome (PCOS)

Nuala Mcbride


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Polycystic Ovary Syndrome (PCOS)

Polycystic Ovary Syndrome (PCOS)

The NHS estimates that PCOS effects 1 in 5 women in the UK. PCOS is where a large number of small egg follicles (approx 8mm in size) occur in the ovaries and is often accompanied by hormonal imbalances (Glenville, 2014). Cysts are where there is a small abnormal growth on the ovaries with fluid filled sacs (Glenville, 2014).  Cysts are sometimes referred to in association with PCOS; but PCOS differs as it is small egg follicles not abnormal growth.

What Is PCOS? 

During a woman’s menstrual cycle follicles grow on the ovaries. Within each of these follicles an egg develops. Once one of these reaches maturity it will be released into the Fallopian tubes (which is known as ovulation). The other follicles will degenerate. However, in the case of polycystic ovaries the ovaries are much larger than normal and there are a number of underdeveloped follicles that appear in clumps (looking somewhat like a bunch of grapes) (Glenville, 2014). This can occur in women and go unnoticed. The problems start to occur when these growths lead to an imbalance in hormones; which produces noticeable symptoms. It is these symptoms that differentiate polycystic ovaries and polycystic ovary syndrome (POCS). 

Underlying causes of PCOS

It’s identified that some women have a predisposition to PCOS due to gestational diabetes of the mother, childhood obesity, borderline adrenal hyperplasia or thyroid issues (Insler and Lunenfeld, 1991). However, there is no definite cause of PCOS. PCOS is classified as a pre-diabetic condition and therefore it is related to faulty blood sugar regulation. Some argue that it’s not clear whether people become overweight and then hormone imbalances arise or vice versa (Glenville, 2014). Whereas, others like Lustig (2012) argue that it’s due to people’s biochemistry that leads to obesity and thus hormone imbalances.

After food is ingested, the blood glucose levels rise, signalling to the pancreas to release insulin (Lustig, 2012). Insulin is then converted into glycogen (liver fat stores), which lowers the blood glucose levels. The fat then makes leptin which feeds back to hypothalamus and decreases your insulin by reducing your appetite and limiting your energy intake (Lustig, 2012). With diets higher in refined carbohydrates, the pancreas is under more pressure to produce insulin, causing the cells to become swamped with insulin. In response the cells down regulate their insulin receptors, resulting in less glucose being taken into the cells. This indicates to the pancreas that yet more insulin needs to be released. This leads to insulin resistance and hypoglycemia. 

With more circulating insulin, there is an imbalance of estrogen; which suppresses thyroid activity. Another study found that high leptin levels were associated with elevated testosterone levels; again indicating the link between androgen production and blood sugar levels (Chakrabarti, 2013). Therefore the fluctuating levels in insulin and leptin associated with blood sugar imbalance, leads to an imbalance in the hormones produced in the ovaries. 

Sex hormone-binding goblulin (SHBG) is a protien produced by the liver that binds to sex hormonnes such as the oestrogen and testerone to control how much of them are circulating in the blood at any one time. Studies have shown that overweight women have lower levels of SHBG in their blood and thus there are more sex hormones circulating in the blood at any one time (Kiddy et al., 1990). These then lead to the symptoms of hirsutism (additional body hair growth). 

How is it diagnosed?
Polycystic Ovaries are usually diagnosed via an ultrasound on the womb as well as hormone blood tests by doctors (Glenville, 2014). It is important to have these hormone blood tests done early on in the menstrual cycle and to note that the pill will affect the results of these tests. Blood tests can reveal a hormone imbalance which can include:

  • High levels of LH (luteinizing hormone)
    • This hormone controls the release of an egg from the ovary.
  • Higher than normal male hormones (e.g. testosterone)
    • This is produced in the ovaries. 
  • Low progesterone
    • This is produced in the ovaries. 
  • It is also good to measure FSH, prolactin levels and thyroid function. 

PCOS Symptoms

There are a multitude of symptoms that PCOS can cause, such no or few periods, acne or oily skin, heavy body hair (often on face, breasts and inside of the legs), susceptible to mood swings or problems with fertility and miscarriages (Glenville, 2014). These all stem from the hormone imbalances in the body.

The NHS outlines 3 key symptoms (of which you need to experience two out of three to be diagnosed): 

  • Irregular periods – meaning you don’t ovulate regularly. 
  • Excess androgen – high levels of “male” hormones in your body, which may cause physical signs such as excess facial or body hair.
  • Polycystic ovaries – your ovaries become enlarged and contain many fluid-filled sacs (follicles) that surround the eggs (but despite the name, you do not actually have cysts if you have PCOS)



Chakrabarti, J., 2013. Serum leptin level in women with polycystic ovary syndrome: Correlation with adiposity, insulin, and circulating testosterone. Annals of Medical and Health Sciences Research, 3(2), p.191.

Glenville, M., 2014. The Nutritional Health Handbook For Women. 5th ed. London: Piatkus.

Insler, V. and Lunenfeld, B., 1991. Pathophysiology of Polycystic Ovarian Disease: New Insights. Human Reproduction, 6(8), pp.1025-1029.

Kiddy, D., Sharp, P., White, D., Scanlon, M., Mason, H., Bray, C., Polson, D., Reed, M. and Franks, S., 1990. Differences in clinical and endocrine features between obese and non-obese subjects with PCOS: An analysis of 263 consecutive cases. Clinical Endocrinology, 32(2), pp.213-220.

Lustig, R., 2012. Fat Chance. 1st ed. New York: Hudson Street Press.

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Hi! I'm Nuala

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