Polycystic ovary syndrome, or polycystic ovarian syndrome (PCOS), is the most common endocrine disorder in women of reproductive age. The syndrome is named after cysts which form on the ovaries of some people with this condition, though this is not a universal symptom, and not the underlying cause of the disorder.
Women with PCOS may experience irregular menstrual periods, heavy periods, excess hair, acne, pelvic pain, difficulty getting pregnant, and patches of thick, darker, velvety skin. The primary characteristics of this syndrome include: hyperandrogenism, anovulation, insulin resistance, and neuroendocrine disruption.
A review of international evidence found that the prevalence of PCOS could be as high as 26% among some populations, though ranges between 4% and 18% are reported for general populations.
The exact cause of PCOS remains uncertain, and treatment involves management of symptoms using medication.
Two definitions are commonly used:
NIH
In 1990 a consensus workshop sponsored by the NIH/NICHD suggested that a person has PCOS if they have all of the following:
oligoovulation
signs of androgen excess (clinical or biochemical)
exclusion of other disorders that can result in menstrual irregularity and hyperandrogenism
Rotterdam
In 2003 a consensus workshop sponsored by ESHRE/ASRM in Rotterdam indicated PCOS to be present if any two out of three criteria are met, in the absence of other entities that might cause these findings:
oligoovulation and/or anovulation
excess androgen activity
polycystic ovaries (by gynecologic ultrasound)
The Rotterdam definition is wider, including many more women, the most notable ones being women without androgen excess. Critics say that findings obtained from the study of women with androgen excess cannot necessarily be extrapolated to women without androgen excess.