Human embryos obtained as a result of fertilization of the oocytes by the spermatozoa can be stored for future use. This is done through Vitrification. Vitrification is an ultra-rapid process that is used to freeze human embryos. In the process there is an instant solidification of the solution without formation of ice crystals. The viscosity of the solution is increased during cooling. This process reduces the damage to the embryos due to formation of ice crystals and results in increased survival rates and pregnancy rates post thawing.
In classic freezing method, the embryos are cooled at the rate of 0.3 ˚C/minute until they reach a temperature of -30˚C and care is taken that the water inside and surrounding the embryo does not become ice. But in case of vitrification, the cells are super cooled at the rate of approximately 5000˚C/minute such that there is no formation of ice. Instead it results in the formation of a gel like substance that causes no damage to the cells.
At Momsoon, we employ this super -fast method to freeze leftover embryos in our IVF programs. The embryo may be frozen when it is 4 -5 days of fertilization when it has divided and is in blastocyst stage. In addition to providing better pregnancy rates, this method also reduces the risk of multiple pregnancies. This is because we transfer fewer embryos for implant since we have the possibility of embryo transfer later.