2.1. General background of polycystic ovary syndrome (PCOS)

As early as 1844, Chereau described sclerocystic changes in the human ovary (Chereau 1844). Although occasional reports on this condition continued to appear over the years, more interest was aroused in 1935 when bilateral polycystic ovaries were related by Stein and Leventhal in a clinical syndrome consisting of “menstrual irregularity featuring amenorrhea, a history of infertility, masculine type hirsutism and, less consistently, obesity (Stein & Leventhal 1935). The condition was for a long time called the Stein-Leventhal syndrome.

In 1958 McArthur and coworkers observed elevated LH levels in women with polycystic ovaries (MacArthur et al. 1958) and the introduction of radioimmunoassays (RIAs) in 1971 stimulated reliance on a biochemical diagnosis. Although it was suspected as early as 1962 that there was a wide variety of clinical presentation of PCOS, the concept of PCOS with normal LH concentrations was not conceived until 1976 (Rebar et al. 1976). The next milestone was the discovery of the association of PCOS and insulin resistance by Kahn and coworkers (Kahn et al. 1976) and Burghen et al. (Burghen et al. 1980). The ultrasonographic finding of polycystic ovaries was described for the first time in 1981 (Swanson et al. 1981). Adams and coworkers introduced a definition for the ultrasonographic appearance of PCO in 1985 as one diagnostic criterion of PCOS (Adams et al. 1985). This has been widely used thereafter, especially in Europe.