Quantitation by image analysis of global DNA methylation in human spermatozoa and its prognostic value in in vitro fertilization: a preliminary study

OBJECTIVE: To determine the relationship between sperm DNA methylation level and sperm characteristics and pregnancy rates. DESIGN: Prospective study. Quantitation by image analysis of DNA methylation in sperm nucleus. SETTING: Department of Reproduction Biology, Edouard Herriot Hospital, Lyon, France. PATIENT(S): Infertile couples undergoing IVF-ET. INTERVENTION(S): The immunostaining of 5 methyl-cytosine was performed on the spare sperm suspension that was used for an assisted reproduction technology procedure. MAIN OUTCOME MEASURE(S): Sperm characteristics according to World Health Organization criteria, sperm motility parameters with computer-assisted semen analysis, sperm DNA methylation level, and heterogeneity index (HI). RESULT(S): Sperm DNA methylation level and HI are correlated with sperm DNA characteristics. HI is negatively correlated with fertilization rate; sperm DNA methylation level is correlated with pregnancy rate. CONCLUSION(S): The DNA methylation level in human spermatozoa could be a new approach to evaluating the ability of spermatozoa to fertilize and lead to normal embryo development.