Polycystic ovarian syndrome (PCOS)

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, occurring in 4% to 6% of the female population. PCOS is a complex of symptoms often associated with obesity, type 2 diabetes, metabolic syndrome, and infertility. Historically there had been a lack of consensus regarding the features that define PCOS. In 2003 a consensus statement was developed between the European and American reproductive societies, known as the Rotterdam criteria, which standardized the definition of PCOS. The diagnosis requires two of the following three findings: (1) oligo-ovulation or anovulation, (2) clinical or biochemical signs of hyperandrogenism, (3) polycystic ovaries on ultrasound. It is important to note that the sonographic appearance of the ovaries is not always required for this diagnosis. The Rotterdam criteria clarify the difference between polycystic ovaries (PCO), which is a diagnostic finding, and PCOS, which is a diagnosis affecting multiple organ systems.

The Rotterdam sonographic definition of a PCO is the presence of either 12 or more follicles measuring 2 to 9 mm in diameter or an ovary that has an increased ovarian volume defined as greater than 10 cm³ (ovarian volume is calculated using simplified formula for prolate ellipsoid = 0.5 × length × width × thickness). Only one ovary with these findings is required with the following two exceptions.