What causes PCOS?
The exact cause is not totally clear. Several factors probably play a part. These include the following.
Insulin
A raised level of insulin in the bloodstream is thought to be the main underlying reason why PCOS develops. Insulin is a hormone that you make in your pancreas (a gland behind your stomach). The main role of insulin is to control your blood sugar level. Insulin acts mainly on fat and muscle cells which take in sugar (glucose) when your blood sugar level rises.
Women with PCOS have what is called 'insulin resistance'. This means that cells in the body are resistant to the effect of a normal level of insulin. Therefore, the level of insulin in the blood needs to be higher than normal to control the blood sugar level. So, to keep the level of sugar in the blood normal, you make more insulin. A 'side effect' of a high blood level of insulin is to cause the ovaries to make too much testosterone (male hormone). A high level of insulin and testosterone interfere with the normal development of follicles in the ovaries. As a result, many follicles tend to develop but often do not develop fully.
Luteinising hormone (LH)
This hormone is also probably involved in causing PCOS. You make this hormone in your pituitary gland. LH stimulates the ovaries to ovulate, and to make certain hormones. A high level of LH may affect the ovaries in some abnormal way. A raised level of LH is found in about 4 in 10 women with PCOS. It may be that a high level of insulin and a high level of LH work together to cause more testosterone than normal to be made in the ovaries.
Hereditary factors
Your genetic makeup is probably important. One or more genes may make you more prone to develop PCOS. PCOS is not strictly inherited from parents to children, but it may run in some families.
Weight
Being overweight or obese is not the underlying cause of PCOS. However, if you are overweight or obese it may make things worse. Excess fat can make insulin resistance worse, which may then cause the level of insulin to rise even further.
However, PCOS may also be a contributing cause of overweight and obesity. This is because high levels of insulin can contribute to weight gain.
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claire, about 1 year
i think i have pcos i have all the symptoms i have also started some treatment from my doctor however i still feel very low with it all is this all part of having pcos?
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sharon, 3 months
i was diagnosed with pcos and didn't fully understand why until researching myself. i can cope with only ovulating, say, twice a year (it definitely saves on tampons!) but the hirsutism on sideburns and neck is just depressing. i am now taking metformin to control insulin and taking more excercise. this is very important to get your body working more efficiently and also helps with depression. i read also that vitamin d deficiency is common in women with pcos so get out in the sun! grill your doctor - go prepared with questions written down so you don't forget. pcos doesn't have to control your life :) take the bull by the horns!
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