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).
It's complex because there are some very typical appearances in the ovaries that give the condition its name. But these are not always present and do not have to be present.
In PCOS, the ovaries are generally bigger than average. 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).
There are also characteristic changes in the appearance of the ovaries on an
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, and generally do not exceed 10mm in size and rarely, if ever, grow to maturity and ovulate.
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 doesn't have
regular periods and may go for many weeks without a period. Other features of the condition are excess weight and body hair.
The condition is relatively common among
infertile women. If affects up to 10 per cent of all women between the ages of 15 and 50 and is 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 an ultrasound examination. But most have no other symptoms or signs of PCOS and have no health problems. The ultrasound appearance is also found in up to 14 per cent of women on the
oral contraceptive pill.
What causes PCOS?
While it's not certain if women are born with this condition, PCOS seems to run in families. This means that something that induces the condition is inheritable, and therefore influenced by one or more genes.
Ongoing research is trying to clarify whether there's a clearly identifiable gene for PCOS. Several different genes have been implicated in the condition – none have been definitely implicated as being the prime cause. Perhaps this role of several genes, and not one in particular, is what lies behind the way in which the condition is expressed so differently in people.
We know that PCOS has some genetic basis, but it's unlikely that all women with one or more of these genes will develop the condition. It's more likely to develop, if there's a family history of
diabetes (especially Type 2, the less severe type usually controlled by tablets) or if there's early
baldness in the men in the family.
When the genetic tendency for PCOS is passed down through 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.
A number of marker proteins have also been identified in the blood of women with PCOS, further supporting the view that this is a genetically determined disorder.
Women are also more at risk if they're
overweight. Maintaining weight or
body mass index (BMI) below a critical threshold is probably 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 overweight (BMI 25 to 30) or obese (with BMI greater than 30), weight loss improves the hormonal abnormalities and improves the likelihood of ovulation and therefore pregnancy.
Can PCOS be prevented?
Not being certain of the exact cause makes it difficult to answer this question fully.
If there's a genetic influence, some people are more likely to get PCOS than others. But it seems likely that you cannot alter your predisposition to PCOS.
There's 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, particularly if you have strong indicators that PCOS could affect you.
These indicators include:
What are the symptoms?
The ways that 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 and 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, some of which can be relatively easier understood in the light of the hormone abnormalities that are frequently found.
These include:
- 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
- raised levels of anti-Mullerian hormone, when compared with women with normal regular cycles (this may become a more useful and accurate test than checking LH or the LH to FSH ratio).
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 with PCOS.
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 (particular time points in the cycle are important for some of these)
- 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 – 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.
Weight loss is effective in reducing male hormone levels, increasing the likelihood of ovulation and getting pregnant.
Using medications to lose weight may be effective, and orlistat is probably the most effective of these. Metformin on the other hand is probably not effective in helping to lose weight though evidence on this is conflicting.
It's interesting that despite all the research into PCOS, the exact relationship between the condition and weight gain (or loss) is unclear. But being overweight, and especially increased abdominal fat, seems to be a strong predictor of having other hormonal problems – such as raised male hormones and tendencies to having diabetes.
What can your doctor do?
Your family doctor will be able to provide many of the drug treatments available (although these are probably best taken in consultation with a specialist). Treatments aim to improve several aspects of PCOS, including:
- fertility, via the stimulation of ovulation
- reduction of the insulin resistance
- reduction of the increased hair.
Treatments
The range of treatments available and their application are listed in Tables 1 and 2.
Table 1 deals with the treatments for improving fertility in women with PCOS (Homberg, 1998; Pirwany et al, 1999; Farquhar et al, 2000; Hughes et al, 2000a; Hughes et al, 2000b; Hughes et al, 2000c).
Table 2 deals with the treatments for other features of PCOS including hirsutism, irregular or absent periods and obesity. The evidence in favour of using of these medications to improve symptoms is not strong and reviewed elsewhere in detail.
