What are polycystic ovaries?

Polycystic ovaries (PCO) are ovaries that have a “polycystic” appearance. PCO is not the same as PCOS. The term polycystic is a misnomer since so-called polycystic ovaries do not contain typical cysts, which in Gynaecology usually refers to a cystic swelling at least 5 cm in diameter. Polycystic ovaries refer to the presence on ultrasound scan of multiple immature follicles measuring 2-9 mm (less than 1 cm) in diameter.