Functional categorization of polycystic ovary syndrome in relationship to source of androgen and its prevalence

Functional categorization of PCOS in relationship to source of androgen and its prevalence. Most PCOS is due to primary FOH; approximately 30% of these have an associated primary functional adrenal hyperandrogenism. Approximately two-thirds of those with PCOS have functionally typical PCOS, ie, they have typical FOH, which is characterized by hyperresponsiveness of 17-OHP to a GnRHa or hCG test. The remaining one-third of PCOS have functionally atypical PCOS, lacking 17-OHP hyperresponsiveness. Most of these have functionally atypical FOH, in which ovarian androgen excess is indicated by a dexamethasone androgen-suppression test. A small number are due to isolated functional adrenal hyperandrogenism. In a minority of cases, the source of androgen cannot be identified as ovarian or adrenal: Most of these have the functionally atypical PCOS of obesity; the source of the androgen is otherwise unexplained (idiopathic) in less than 20% of the functionally atypical PCOS group (less than 1% of PCOS).