A guide to understanding polycystic ovary syndrome (PCOS).

Polycystic ovary syndrome (PCOS) is the commonest endocrine disorder affecting women of reproductive age. Some 20% of women will have polycystic ovaries on an ultrasound scan and around 7% of women have the additional clinical or biochemical features of PCOS. As a complex multisystem disorder its background can be confusing to understand. They key feature, however, is an increased production of androgen by the ovaries. This review uses ovarian biology to describe a strategy to aid understanding and explanation of PCOS. This framework can be also be used to teach about PCOS and to inform different approaches to its management. Published by the BMJ Publishing Group Limited.