Serum IGF-1 concentrations following pituitary desensitization do not predict the ovarian response to gonadotrophin stimulation prior to IVF

BACKGROUND: Insulin-like growth factor-1 (IGF-1) is known to play a role in ovarian follicular development augmenting the action of FSH. Low intrafollicular concentrations have been detected in women who respond poorly to gonadotrophins. This study addresses the relationship between serum IGF-1 levels following pituitary desensitization and ovarian response to gonadotrophin stimulation. METHODS: This is a case-control study of 78 patients undergoing IVF-embryo transfer treatment. Thirty-nine strictly-defined poor responder patients requiring 50 or more ampoules (75 IU FSH) to reach oocyte retrieval were compared with 39 age-matched normal responders, requiring fewer than 50 ampoules. IGF-1 concentrations were determined by extraction radioimmunoassay on serum samples obtained after pituitary desensitization but prior to gonadotrophin stimulation. RESULTS: Despite highly significant differences in measures of ovarian response between groups, the mean serum IGF-1 concentration was not statistically significantly different between poor and normal responders [(31.5 nmol/l [95% confidence interval (CI) 28.5-34.5] versus 34.5 nmol/l (95% CI 31.8-37.2)] respectively. No correlation between oocyte number or total gonadotrophin used and serum IGF-1 concentration was observed. CONCLUSION: Whilst IGF-1 influences ovarian follicular development this study suggests that serum IGF-1 does not predict ovarian response and does not differentiate between critically-defined poor and normal responders.