Embryos not used in the current cycle could be cryopreserved. Cryopreservation is often achieved with vitrification, a immediate freezing approach. Vitrification is thought to prevent cryoinjury by reducing the event of intracellular crystals.[35] All embryos can also be frozen in individuals in danger for ovarian hyperstimulation syndrome (mentioned more in https://www.ivf.com.mx/