Dynamics of FSH-induced follicular growth in subfertile women: relationship with age, insulin resistance, oocyte yield and anti-Mullerian hormone

BACKGROUND: During excess FSH treatment, different categories of follicles can be discerned: those responding and appearing to grow immediately (FoIsS8) and those appearing subsequently during the follicular phase (FoIs/d). These follicular categories were explored in cycles of assisted reproduction in the context of follicular biology, including primordial follicle pool (PFP) depletion, age, insulin resistance and potential markers. METHODS: Follicular cohorts were examined in 365 conventional ART cycles and related to patient insulin sensitivity, plasma FSH and anti-Mullerian hormone (AMH). RESULTS: Age had no influence upon the FoIsS8 category but was associated with a significant (P < 0.005) decline in the Fols/d. In contrast, insulin-resistant polycystic ovary syndrome (IR-PCOS) showed a significant (P = 0.005) increase in FoIsS8. Circulating AMH correlated strongly with oocyte yield and FoIs/d. CONCLUSION: Age showed little impact on the initial follicular cohort, but a significant impact upon the secondary cohort, while insulin resistance appeared to promote the former category alone. The disturbance to follicular dynamics and AMH in IR-PCOS reflected a larger stockpile of FSH-sensitive follicles. Circulating AMH appears to represent all categories of antral follicles observed.