ABSTRACT
Cryopreservation of embryos increases considerably the overall efficiency and safety of human assisted reproduction, and also offers a solution for various problems where delay of transfer of the given embryos is required. The purpose of this chapter is to review the current major strategy—vitrification—that is used worldwide for embryo cryopreservation.
Vitrification permits a virtually perfect survival of embryos, which in return now allows a completely new approach to how we treat IVF patients. The near perfect survival of embryos allows to avoid fresh transfers without affecting implantation and pregnancy rates.
Today the major discussion is not about when to use the “freeze all” approach for IVF treatment, but, rather, if there is still reason to perform fresh embryo transfer.
