Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting 4–8% of women worldwide. It is characterized by multiple cysts on the ovary, amenorrhea or oligomenorrhea, and increased androgens. Although the exact cause remains unknown, it is hypothesized that increased levels of circulating androgens is what results in secondary amenorrhea. PCOS may also be a cause of primary amenorrhea if androgen access is present prior to menarche. Although multiple cysts on the ovary are characteristic of the syndrome, this has not been noted to be a cause of the disease.
