This randomized study compares three different freezing methods to store human in vitro
fertilization (IVF) embryos: vitrification with two commercial kits or slow freezing. After
information, all patients undergoing IVF treatment can be included in the study. If
qualified, embryos at different developmental stages will be allocated between the three
methods. At the end of the first year survival and developmental rates, and implantation and
pregnancy rates will be analyzed in order to determine the best method.