Alterations in thyroid function among the different polycystic ovary syndrome phenotypes.

The study evaluates the prevalence of subclinical thyroid dysfunction in infertile PCOS patients, according to the different PCOS phenotypes and to examine whether insulin sensitizers in insulin resistant (IR) PCOS patients may improve thyroid function. The study population consisted of all PCOS patients, attending the infertility and IVF unit of Department of Pediatrics, Obstetrics and Reproductive Medicine of University of Siena, Italy, and compared them to regularly cycling, healthy, infertile controls. Upon admission, blood was drawn from all patients during the early follicular phase, for complete hormonal and metabolic profiles. In IR-PCOS patients treated with insulin sensitizers, blood was drawn again after 6 months. PCOS patients had a significantly higher prevalence of subclinical thyroid dysfunction compared to infertile controls. While no significant association was detected between TSH value and the presence of hyperandrogenism, overweight and obese PCOS patients, as well as IR PCOS patients showed significantly higher prevalence of subclinical thyroid dysfunction. Moreover, among IR PCOS patients, 6 months treatment with insulin sensitizers significantly reduces TSH levels. Infertile PCOS patients have a high prevalence of subclinical thyroid dysfunction, which may be successfully treated in IR PCOS patients by insulin sensitizers.