Polycystic ovary syndrome (PCOS) is a frustrating experience for an increasing number of women, a complex syndrome for managing clinicians, and a scientific challenge for researchers. As research in the area is rapidly advancing and a greater understanding of the condition evolving, it is important that this information is provided to women with PCOS and health care professionals alike.

PCOS is the most common endocrine abnormality in reproductive-aged women. Its prevalence, estimated at around 6-9% of reproductive-aged women, has recently been noted at 28% of unselected obese and 5% of lean women.^1,2 PCOS is estimated to affect about 400,000 women in Australia.

Obesity and excess weight is a major chronic disease in Western countries. Obesity increases hyperandrogenism, hirsutism, infertility and pregnancy complications both independently and by exacerbating PCOS. Obesity also increases the risk of type 2 diabetes and cardiovascular disease. Indeed, obesity is known to exacerbate most features of PCOS, and its rising prevalence is reflected in the apparent increasing prevalence of the short- and long-term clinical features of PCOS.

However, aside from reproductive features PCOS has psychological and metabolic features as well. Based on US data, the anticipated economic burden of PCOS in Australia in 2006 was $40 million (menstrual dysfunction 31%, infertility 12% and PCOS-associated diabetes 40% of total costs), representing a major health and economic burden.

Definition of PCOS

Until recently no universally accepted clinical definition existed for PCOS. During the past three decades research has revealed that PCOS is a heterogeneous condition. The initial National Institutes of Health (NIH) diagnostic criteria based on oligomenorrhoea/amenorrhoea and clinical or biochemical hyperandrogenism were broadened in the 2003 Rotterdam criteria to include polycystic ovaries (PCO) at ultrasound in the key diagnostic criteria.

Twenty-five per cent of young women have PCO on ultrasound, and the inclusion of PCO in the diagnostic criteria has increased the prevalence of PCOS. More recently the Androgen Excess Society suggested the diagnostic criteria should be modified to
exclude those without symptoms, that is, those with PCO on ultrasound and oligomenorrhoea/amenorrhoea but no hyperandrogenism, in whom other causes such as hypogonadotrophic hypogonadism are common.

With the four key diagnostic features (oligomenorrhoea/amenorrhoea, clinical or biochemical hyperandrogenism and PCO on ultrasound), there are 16 different presentations which are grouped into four main phenotypes (table 1). The possible phenotypes shown in table 1 demonstrate the heterogeneity of the condition based on the key diagnostic features. It should be noted that PCOS is a diagnosis of exclusion, and conditions such as thyroid dysfunction and hyperprolactinaemia should be excluded biochemically, while rarer conditions should primarily be excluded clinically (Cushing’s syndrome, virilising tumours, etc).

Obesity, insulin resistance and metabolic syndrome are key features of the condition but are not currently part of the diagnostic criteria. However, hyperinsulinaemia drives hyperandrogenism through several different mechanisms (table 2). The  measurement of insulin resistance remains flawed and is not recommended in clinical practice. This is one of the key reasons it is not currently included in the diagnostic criteria.

The reason for the evolving diagnostic criteria and the ongoing controversy relate back to the lack of a clear understanding of the aetiology of PCOS. However, currently the Rotterdam criteria are the agreed diagnostic criteria for defining PCOS. Further research is needed to clarify the aetiology of PCOS and to allow further definition of the condition, including division into different subcategories.

This article first appeared in Australian Doctor, How to treat on 29 August 2008 and has been reproduced here with permission.

 Australian Doctor, How to treat: Polycystic ovary syndrome 437.44 Kb

Content Updated 20 November, 2009