Diagnostic Criteria for Polycystic Ovary Syndrome (PCOS)

The Rotterdam Criteria

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Though a common disorder, polycystic ovary syndrome (PCOS) is not well understood. There isn't a clear consensus about how PCOS is diagnosed, especially among adolescent girls. Part of the confusion is due to the diagnostic criteria itself, which have previously included two different sets: the National Institutes of Health and the Rotterdam panel.

This article reviews the Rotterdam criteria for diagnosing PCOS.

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History of the PCOS Criteria

In the past, there were two separate sets of diagnostic criteria for PCOS: one issued by the National Institutes of Health (NIH) and another released by an international panel in Rotterdam which expanded upon the NIH guidelines.

The differences were minor but striking. Chief among these was the inclusion of polycystic ovaries as one of the three diagnostic criteria for PCOS. The Rotterdam panel included them, while the NIH did not.

It was only in December 2012 that NIH formally endorsed the Rotterdam criteria and recommended that it be adopted by all health professionals.

The Rotterdam Criteria

Under the Rotterdam definition, a woman must meet at least two of three criteria in order to be positively diagnosed with PCOS. These include irregular and/or no ovulation, high androgen levels, and the presence of polycystic ovaries.

The rationale for the Rotterdam criteria can be summarized as follows:

  • Irregular and/or no ovulation is caused by an imbalance of sex hormones, including high levels of testosterone and luteinizing hormone. As a result, some women with PCOS will have a period several times each month, every few months, or not at all. Periods can oftentimes be heavy and accompanied by large clots. Basically, f a woman has eight or fewer menstrual cycles per year, she meets the criteria.
  • High androgen levels are considered key to diagnosing PCOS even though some women with the disorder do not have excess androgen. As such, either serological (blood) or clinical evidence would be accepted. Blood tests with high androgen levels (total and free testosterone, DHEA-sulfate) is enough to satisfy the criteria. In the absence of this, hair loss, acne, and excessive central body hair growth meet the clinical criteria for PCOS.
  • Polycystic ovaries refer to the presence of 12 or more small follicles in each ovary. The follicles sometimes referred to as cysts, resemble a string of pearls. As with androgen levels, women with PCOs do not necessarily have cysts. A transvaginal ultrasound is a primary tool for investigation. The follicles themselves are the result of the hormonal imbalance, not the cause of it.

Finally, in order to provide a definitive diagnosis, the doctor will need to investigate whether there are any other causes for the abnormalities. Ultimately, PCOS is a condition of exclusions. This means that the clinician would need to rule out things like congenital adrenal hyperplasia (CAH), which causes high testosterone, or elevated prolactin levels, which can affect ovulation.

Because the current criteria can include women with or without polycystic ovaries, recommendations have been made to change the name of PCOS and entirely removes any allusion to the term "cyst."

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  • National Institutes of Health. “Polycystic Ovary Syndrome (PCOS): Final Panel Report.” Evidence-based Methodology Workshop on Polycystic Ovary Syndrome; Rockville, Maryland; December 3-5, 2012.

By Angela Grassi, MS, RDN, LDN
 Angela Grassi, MS, RDN, LDN, is the founder of the PCOS Nutrition Center.