What is polycystic ovary syndrome?

Polycystic ovary syndrome (PCOS), formerly known as the Stein-Leventhal syndrome, is a condition where at least two of the following occur, and often all three:

• At least 12 follicles (tiny cysts) develop in your ovaries. (Polycystic means many cysts.)
• The balance of hormones that you make in the ovaries is altered. In particular, your ovaries make more testosterone (male hormone) than normal.
• You do not ovulate each month. Some women do not ovulate at all. In PCOS, although the ovaries usually have many follicles, they do not develop fully and so ovulation often does not occur. If you do not ovulate then you do not have a period.

Therefore, it is possible to have polycystic ovaries without the typical symptoms that are in the syndrome. It is also possible to have PCOS without multiple cysts in the ovary.

How common is polycystic ovary syndrome?

PCOS is common. Research studies of women who had an ultrasound scan of their ovaries found that up to 1 in 4 young women have polycystic ovaries (ovaries with many small cysts). However, many of these women were healthy, ovulated normally, and did not have high levels of male hormones.
It is thought that up to 1 in 10 women have polycystic ovary syndrome (PCOS) - that is, at least two of: polycystic ovaries, a raised level of male hormone, reduced ovulation. However, these figures may be higher.

What causes polycystic ovary syndrome?

The exact cause is not totally clear. Several factors probably play a part. These include the following:

Insulin

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 causing them to take in sugar (glucose) when your blood sugar level rises. Another effect of insulin is to act on the ovaries to cause them to produce testosterone (male hormone).
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. More insulin is produced to keep the blood sugar normal. This raised level of insulin in the bloodstream is thought to be the main underlying reason why PCOS develops. It causes the ovaries to make too much testosterone. 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. This causes problems with ovulation: hence period problems and reduced fertility.
It is this increased testosterone level in the blood that causes excess hair growth on the body and thinning of the scalp hair.
Increased insulin also contributes towards weight gain.

Luteinising hormone (LH)

This hormone is made in the pituitary gland. It stimulates the ovaries to ovulate and works alongside insulin to promote testosterone production. A high level of LH is found in about 4 in 10 women with PCOS. A high LH level combined with a high insulin level means that the ovaries are likely to produce too much testosterone.

Hereditary factors

Your genetic makeup is probably important. One or more genes may make you more prone to developing 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, excess fat can make insulin resistance worse. This may then cause the level of insulin to rise even further. High levels of insulin can contribute to further weight gain producing a 'vicious cycle'. Losing weight, although difficult, can help break this cycle.

What are the symptoms and problems of polycystic ovary syndrome?

Symptoms that occur if you do not ovulate

• Period problems occur in about 7 in 10 women with PCOS. You may have irregular or light periods, or no periods at all.
• Fertility problems - you need to ovulate to become pregnant. You may not ovulate each month, and some women with PCOS do not ovulate at all. PCOS is one of the most common causes of infertility.

Symptoms that can occur if you make too much testosterone (male hormone)

• Excess hair growth (hirsutism) occurs in more than half of women with PCOS. It is mainly on the face, lower abdomen, and chest. This is the only symptom in some cases.
• Acne may persist beyond the normal teenage years.
• Thinning of scalp hair (similar to male pattern baldness) occurs in some cases .

Other symptoms

Weight gain- about 4 in 10 women with PCOS become overweight or obese.

Depression or poor self-esteem may develop as a result of the other symptoms.

Symptoms typically begin in the late teens or early 20s. Not all symptoms occur in all women with PCOS. For example, some women with PCOS have some excess hair growth, but have normal periods and fertility.
Symptoms can vary from mild to severe. For example, mild unwanted hair is normal, and it can be difficult to say when it becomes abnormal in women with mild PCOS. At the other extreme, women with severe PCOS can have marked hair growth, infertility, and obesity. Symptoms may also change over the years. For example, acne may become less of a problem in middle age, but hair growth may become more noticeable.