PCOS or polycystic ovarian syndrome is a very common condition that affects millions of reproductive-age women (or about 5-10% in the US). However, it is a hugely misunderstood and over-diagnosed condition that needs a fair bit of clarification. To do this we need to understand the meaning of polycystic ovaries.

Now it must be emphasized that ALL ovaries exhibit cysts to an extent. Usually, they are very small and these are the cysts (also known as antral follicles) that have eggs inside them. They are usually spread out randomly throughout the ovary. However, in women with polycystic-appearing ovaries, these small cysts are typically pushed to the other edge of the ovary. In addition, there usually are a lot of these displaced cysts, at least 12 in one or both ovaries. The quantity and placement of these cysts have led to them being called a “string of pearls”.

When the ovaries have this appearance, we use the term polycystic ovarian morphology (PCOM). However, this is just a descriptive term, it does NOT mean a woman has PCOS. Around 20% of women who have PCOM, do NOT have PCOS and generally have no fertility issues. Unfortunately, this distinction is not always made and many women are then told they have PCOS without actually meeting the definition of this condition.

When is PCOS diagnosed?

This then brings us to the question of how to define the syndrome, the “S”, in PCOS. Fortunately, we have relatively clear criteria established by numerous societies. One of the most commonly used is the Rotterdam criteria. According to these criteria, a patient has PCOS when at least two of three features are noted.

1. First is PCOM,
2. Second are clinical signs or lab results showing excess male hormones like testosterone, and
3. Third are irregular periods.

Concerning irregular periods, please understand it is OK to miss up to two periods in a calendar year and still be considered to have monthly periods. Many things can affect the timing of a period; such as weight loss, illness, stress, etc. Just because a few periods have been missed does not mean a woman has PCOS.

This tolerance for missed periods is even more important in adolescents and early teenagers who have just started getting their periods. It is very common for periods to be irregular in young women, especially in the first three years after the first menstrual period. This is because the system that regulated the timing of the period is still maturing. Hence, caution must be taken before a young woman is given the label of PCOS.

Could it be something else?

Finally, we need to emphasize the big picture that PCOS, even if highly likely, is a diagnosis of exclusion. This means that even if a patient meets the above criteria, any common medical/endocrine issues that could also be the cause must first be excluded. These include issues with thyroid function, issues with the pituitary gland, and rare but serious conditions such as Cushing’s syndrome and testosterone-producing tumors. Until all other causes are excluded, a woman cannot be definitively labeled as having PCOS.

Once a woman has met the criteria for PCOS and we are sure that there are no other causes, we can then focus on the underlying causes and treatment.

Next – PCOS Part II : What are the lifestyle modification and treatment options? >