Serum insulin-like growth factor I (IGF-I) and IGF-binding protein 3 (IGFBP-3) in IVF patients with polycystic ovary syndrome: correlations with outcome

Abstract

To evaluate serum insulin-like growth factor I (IGF-I) and IGF-binding protein 3 (IGFBP-3) levels during stimulation in polycystic ovary syndrome (PCOS) and control populations as factors predictive of IVF outcome. Observational study. Academic medical center-based IVF practice. Forty-three PCOS and 33 male-factor control patients undergoing IVF from 2002 to 2004. Treatment with a dual suppression protocol incorporating oral contraceptive pills (OCPs) and GnRH agonist suppression followed by low-dose gonadotropin therapy. The PCOS and control patients' serum IGF-I and IGFBP-3 levels were compared and correlated with IVF outcome. PCOS and control patients were comparable in terms of demographics and IVF outcome. In both, mean serum IGF-I levels increased during stimulation. PCOS patients whose IGF-I levels decreased from day 3 to day of hCG had a significantly higher mean number of immature oocytes retrieved (4.8 +/- 1.1 vs. 2.4 +/- 0.4; P=.02). IGFBP-3 levels increased during stimulation in PCOS patients but tended to decrease in control patients. In PCOS patients, an increase in IGFBP-3 levels during stimulation was associated with a greater likelihood of becoming pregnant (P=.03) and of ongoing pregnancy (P=.02). The bioavailability of IGF-I appears to play a key role in oocyte maturation in PCOS patients. Alterations in IGFBP-3 concentration during stimulation may be a critical mechanism in modulating IGF-I activity.