PCOS: Backgrounds, evidence and problems in diagnosing the syndrome

PCOS constitutes a heterogeneous clinical picture harbouring different subsets of patients. Recently an attempt was made to define the diagnosis of PCOS based on existing clinical evidence. Oligo- or anovulation, clinical or biochemical hyperandrogenism and polycystic ovaries constitute the key clinical features on which the diagnosis should be based. No single diagnostic criterion is sufficient for clinical diagnosis. Based on this new consensus the spectrum of women with PCOS has been considerably broadened. The purpose of this paper is to review the evidence for this new classification and to address problems in diagnosing PCOS using these new criteria.