Embryos not used in the current cycle may be cryopreserved. Cryopreservation is usually realized with vitrification, a immediate freezing procedure. Vitrification is assumed to avoid cryoinjury by decreasing the development of intracellular crystals.[35] All embryos can also be frozen in individuals at risk for ovarian hyperstimulation syndrome (talked over even https://www.ivf.com.mx/