Figure 5.

Graphical depiction of the proposed FIGO Ovulatory Disorders Classification System. Note: After the individual is diagnosed with an ovulatory disorder, the core or first level of the system is the allocation to type I, II or III disorders according to their presumed primary source: hypothalamus, pituitary gland or ovary, respectively. PCOS comprises the type IV category and the criteria proposed by WHO are to be used to determine this categorization. The second level stratifies each anatomic category (types I–III) into the known or presumed mechanism according to the ‘GAIN-FIT-PIE’ mnemonic as appropriate and applicable. FIGO, International Federation of Gynecology and Obstetrics; GAIN-FIT-PIE, Genetic, Autoimmune, Iatrogenic, Neoplasm; Functional, Infectious and Inflammatory, Trauma and Vascular; Physiological, Idiopathic, Endocrine; PCOS, polycystic ovary syndrome; WHO, World Health Organization.