statistical analysis The mean number of usable oocytes, transferable and freezable embryos per donor, and the
mean percentage of usable oocytes from collected oocytes, transferable and freezable embryos from usable oocytes were assessed. The results were analyzed by Student’s-t and Chi-squared tests, using ANOVA SPSS Version 11.5 software for Windows (SPSS, Inc., Chicago, IL, USA).