Polycystic ovary syndrome (PCOS) is a very frequent endocrine disease of women in reproductive age, with an estimated prevalence of 5 to 10 % according to the studied population. In 2003 a committee of experts joined in Rotterdam under the auspice of the American Society for Reproductive Medicine and the European Society for Human Reproduction and Embryology, defined diagnostic criteria. It should include unless two of the following: menstrual irregularities; excess of male hormones (clinic or biochemical) and polycystic ovaries under ultrasound examination; giving rise to four subgroups or phenotypes: