Crioconservazione: stato dell'arte.

Cryopreservation was mainly introduced in order to face the increasing number of stimulation cycles per patient and multiple pregnancy during procedures of in vitro fertilization and embryo transfer, accumulating excess embryos and transferring it in a later cycle. Nevertheless embryo storage has several implications because of moral and legal problems. Starting from 1984, date of the first transfer of a cryopreserved embryo, techniques have evolved and cryopreservation is now a reality in many sterility Centers. The aim of this review is then to point out the state of the art of cryopreservation with regard to embryos and oocyte storage and to have a look to possible futures developments in this technique.