What is polycystic ovary syndrome?
Polycystic (literally, many cysts) ovary syndrome (PCOS or PCO) is a complex condition that affects the ovaries (the organs in a woman's body that produce eggs).
In PCOS, the ovaries are bigger than average, and the outer surface of the ovary has an abnormally large number of small follicles (the sac of fluid that grows around the egg under the influence of stimulating hormones from the brain).
In PCOS, these follicles remain immature, never growing to full development or ovulating to produce an egg capable of being fertilised. For the woman this means that she rarely ovulates (releases an egg) and so is less fertile. In addition, she does not have regular periods and may go for many weeks without a period. Other features of the condition are excess weight and excess body hair.
The condition is relatively common among infertile women and particularly common among women with ovulation problems (an incidence of about 75 per cent). In the general population, around 25 per cent of women will have polycystic ovaries seen on ultrasound examination but most have no other symptoms or signs of PCOS and are perfectly healthy. The ultrasound appearance is also found in up to 14 per cent of women on the contraceptive pill.
What causes PCOS?
While it is not known if women are born with this condition, PCOS seems to run in families. This means that something that induces the condition is inheritable, and thus influenced by one or more genes.
Interestingly, when PCOS is passed down the man's side of the family, the men are not infertile, but they do have a tendency to become bald early in life, before the age of 30. Ongoing research is trying to clarify whether there is a clearly identifiable gene for PCOS. It seems likely that in the future one or two genes will be identified that play a fundamental role in determining a woman's likelihood of developing this condition.
Even if PCOS has a genetic basis, it is likely that not all women with the gene or genes will develop the condition. It is more likely to develop if there is a family history of diabetes (especially Type 2, the less severe type usually controlled by tablets), or if there is early baldness in the men in the family.
Women are also more at risk if they are overweight. Maintaining weight or body mass index (BMI) below a critical threshold is probably very important to determine whether some women develop the symptoms and physical features of the condition. Just how much weight (or what level of BMI) is difficult to say because it will be different for each individual. Certainly, for patients who are considered obese (with BMI greater than 30) or overweight (BMI 25 to 30), weight loss improves the hormonal abnormalities and improves the likelihood of ovulation and thus pregnancy.
Can PCOS be prevented?
If there is a genetic influence, then some people are more likely to get PCOS than others. However, it seems likely that you cannot alter your predisposition to PCOS. There is no current proof of any benefit of preventative weight loss, but the best advice for overall health is to maintain a normal weight or BMI, especially if you have strong indicators that PCOS could affect you. These indicators are:
a tendency in the family towards non-insulin dependent (Type 2) diabetes.
a tendency towards early baldness in the men in the family (before 30 years of age).
the knowledge that a close relative already has PCOS.
What are the symptoms?
The ways in which PCOS shows itself include:
absent or infrequent periods (oligomenorrhoea): a common symptom of PCOS. Periods can be as frequent as every five to six weeks, but might only occur once or twice a year, if at all.
increased facial and body hair (hirsutism): usually found under the chin, on the upper lip, forearms, lower legs and on the abdomen (usually a vertical line of hair up to the umbilicus).
acne: usually found only on the face.
infertility: infrequent or absent periods are linked with very occasional ovulation, which significantly reduces the likelihood of conceiving.
overweight/obesity: a common finding in women with PCOS because their body cells are resistant to the sugar-control hormone insulin. This insulin resistance prevents cells using sugar in the blood normally and the sugar is stored as fat instead.
miscarriage (sometimes recurrent): one of the hormonal abnormalities in PCOS, a raised level of luteinising hormone (LH - a hormone produced by the brain that affects ovary function), seems to be linked with miscarriage. Women with raised LH have a higher miscarriage rate (65 per cent of pregnancies end in miscarriage) compared with those who have normal LH values (around 12 per cent miscarriage rate).
These symptoms are related to several internal changes.
Hormonal abnormalities, including:
raised luteinising hormone (LH) in the early part of the menstrual cycle.
raised androgens (male hormones usually found in women in tiny amounts).
lower amounts of the blood protein that carries all sex hormones (sex-hormone-binding globulin).
a small increase in the amount of insulin and cellular resistance to its actions.
Characteristic changes in the appearance of the ovaries on ultrasound scan. The ovaries are polycystic, with many small follicles scattered under the surface of the ovary (usually more than 10 or 15 in each ovary) and almost none in the middle of the ovary. These follicles are all small and immature, generally do not exceed 10mm in size and rarely, if ever, grow to maturity and ovulate.
Most women with PCOS will have the ultrasound findings, whereas the menstrual cycle abnormalities are found in around 66 per cent of women and obesity is found in 40 per cent. The increase in hair and acne are found in up to 70 per cent whereas the hormone abnormalities are found in up to 50 per cent of women.
It is likely that there are different stages of the disease throughout life. Younger women tend to have substantial difficulties with their periods, whereas older women have other problems such as diabetes and hypertension (high blood pressure), though their period patterns tend to become more regular.
Women with PCOS also have an increased risk of strokes and heart attacks, but their death rate from these conditions is not increased (Wild et al, 2000).
Women with PCOS may also have an increased risk of endometrial cancer (cancer of the lining of the womb), particularly if they have infrequent or absent periods.
How is PCOS diagnosed?
The diagnosis is based on the patient's symptoms and physical appearance. If the diagnosis seems likely because the patient's history contains many of the symptoms described already, certain investigations are done to provide confirmatory evidence or to indicate another cause for the symptoms.
These include:
blood tests such as:
female sex hormones (at a certain point in the cycle if possible)
male sex hormones
sex-hormone-binding globulin
glucose
thyroid function tests
other hormones, eg prolactin.
ultrasound examination.
Your own GP can do the initial blood investigations, ensuring they are carried out at the correct time of the cycle if appropriate. Your GP may be able to arrange an ultrasound scan.
Once the diagnosis is made, nothing more needs to be done for some women, eg if their fertility is not an issue, if their weight is within normal limits, and if they do not have excess body hair.
If any of the symptoms are an issue, then further advice and treatment, and possibly specialist referral is needed.
What else could it be?
The other conditions likely to cause abnormal periods include raised levels of prolactin and of thyroid stimulating hormone (TSH). Both these hormones are produced from a particular part of the brain, the anterior pituitary.
Raised prolactin levels can occur together with headaches and some disturbances of vision whereas raised TSH levels indicate low thyroid hormones (hypothyroidism). Both these conditions lead to suppressed ovulation and infertility.
Increased hair and acne reflect an increase in male hormones (androgens) in the blood. Other conditions can cause such an increase.
Rarely, adrenal disorders or tumours cause increased androgens. In these conditions, hirsutism usually develops quite rapidly; previously normal periods may also stop and, occasionally, muscle weakness occurs.
Loss of, or changes in, female aspects of body shape and appearance (secondary sexual characteristics), especially reduction in breast size, may also occur. As the androgen excess progresses, the voice can deepen and the clitoris can increase in size (clitoromegaly). If these serious medical disorders are present, the male hormone levels will be considerably increased, way above those found in PCOS, and specialist treatment should be arranged.
What can you do for PCOS?
There are several things that an individual can do if they have a tendency towards developing some or all of the elements of PCOS. Much of this involves lifestyle changes to ensure that your weight is kept within normal limits (BMI between 19 and 25).
In addition, because there is a likelihood of developing diabetes in later life and a slightly higher risk of heart disease, low-fat and low-sugar options should be considered when making choices about what to eat or to drink.
Weight loss, or maintaining weight below a certain level, will have the short-term benefit of increasing the likelihood of successful treatment and the long-term benefits of reducing the risk of diabetes and heart disease (Galtier-Dereure et al, 1997).
Even more info at
http://www.netdoctor.co.uk/womenshealth/facts/pcos.htm
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