Vitrification and the demise of fresh treatment cycles in ART

Abstract The advent of vitrification has transformed the therapeutic landscape in ART. Clear evidence for this is provided by the dramatic rise in the number of FET cycles being carried out annually. In this article, we review the reasons that underlie this trend and the current evidence that points to the place FET cycles will come to inhabit in the future. Safety issues have been central to the narrative around the clinical application of vitrification and as the evidence base grows, the risk benefit balance will become clearer for different patient groups.  These will include recipient of donor eggs, as in some centres the use of frozen thawed donor eggs now exceeds that of fresh oocytes. Efficient freeze thaw techniques have also impacted on international transport of gametes and embryos, increasing international access. The profound changes that vitrification has brought about promises to fulfil a prediction made by this journal's founding Editor, Bob Edwards, that embryo and egg freezing would solve many of the challenges presented by ART.