The relationships between AMH, androgens, insulin resistance and basal ovarian follicular status in non-obese subfertile women with and without polycystic ovary syndrome

BACKGROUND: Hyperandrogenaemia and insulin resistance are prominent features of polycystic ovary syndrome (PCOS) and influence the process of folliculogenesis in women with the endocrinopathy. Anti-Mullerian hormone (AMH) levels are elevated in women with PCOS and studies including IVF subjects have shown that this is a reliable marker of ovarian performance. The aims of this prospective study were to assess the relationship between insulin resistance, androgens and AMH, and whether AMH contributes to altered folliculogenesis in non-obese women with PCOS. METHODS: A total of 232 IVF candidates, 49 of whom had PCOS according to the Rotterdam 2003 consensus criteria, were recruited. AMH levels and ovarian morphology were assessed. The relationships between AMH and insulin resistance and androgenaemia in patients with and without PCOS were studied. RESULTS: PCOS patients were slightly older than controls (median ages 34 and 30 years, respectively). AMH generally increased with antral follicle count (AFC), insulin, homeostatic model assessment of tissue insulin sensitivity (HOMA-IR), testosterone, free androgen index and luteinising hormone, and decreased with chronological age, homeostatic model assessment of steady state beta cell function (HOMA-B) and serum sex hormone binding globulin (SHBG). For these relationships there were no significant differences in the slopes between PCOS and non-PCOS patients. The ratio of AMH per antral follicle (AMH/AF) was higher in PCOS patients. Both PCOS and non-PCOS groups showed a very similar increase in AMH with increases in AFC, but the PCOS patients had consistently higher AMH across all AFC levels. CONCLUSIONS: These observations indicate that AMH is similarly related to insulin resistance and androgens in women with and without PCOS. This effect appears to be independent of age although an indirect causal effect due to ageing or some other mechanism cannot be ruled out. Excessive granulosa cell activity may be implicated in the abnormal follicular dynamic of the syndrome.