Follicular fluid insulin like growth factor-1 (FF IGF-1) is a biochemical marker of embryo quality and implantation rates in in vitro fertilization cycles

Abstract

CONTEXT:Insulin-like growth factor-1 (IGF-1) has been reported to play a role in human follicular and embryonic development. However, earlier studies carried out mostly in animal models or in culture mediums supplemented with IGF-1 have been unable to directly link IGF-1 with embryo quality. Results correlating IGF-1 with pregnancy outcome have also been ambiguous so far.AIM:The aim of this study is to find if in situ follicular-fluid level of IGF-1 is predictive of embryo quality and implantation rates in in vitro fertilization (IVF) cycles.SETTINGS AND DESIGN:Prospective study involving 120 cycles of conventional IVF-embryo transfer in infertile women.SUBJECTS AND METHODS:IGF-1 concentrations were estimated in pooled follicular-fluid on the day of oocyte-pickup. Embryo quality was assessed daily at different developmental stages. Cycles were sorted into low and high follicular fluid insulin-like growth factor-1 (FF IGF-1) groups according to the median value of measurement. Embryo quality, clinical pregnancy and implantation rate were the main outcome measures.STATISTICAL ANALYSIS:Graph-pad Prism 5 statistical package.RESULTS:FF IGF-1 correlates with embryo quality (Pearson r = 0.3894, r2 = 0.1516, P > 0.0001) and clinical pregnancy (Pearson r = 0.5972, r2 = 0.36, P > 0.0001). High FF IGF-1 group shows significantly higher rates of fertilization, cleavage, blastocyst formation and top grade embryos compared with low FF IGF-1 group. Clinical pregnancy rates (38.33 vs. 20%, P = 0.0272) and embryo implantation rates (21.6 vs. 10.32%, P = 0.0152) are also significantly higher in the high versus low FF IGF-1 group. Threshold value of FF IGF-1 for clinical pregnancy is <58.50 ng/mg protein (receiver operating characteristics AUC : 0.85 ± 0.03, 95% CI: 0.78-0.91).CONCLUSION:FF IGF-1 is a plausible biochemical marker of embryo quality and implantation rate and correlates with clinical pregnancy rates in conventional IVF cycles.