Since 1983 when the first pregnancy with cryopreserved embryos was achieved, the progress of cryogenics has been rapid, thus allowing today the cryopreservation of both embryos and gametes (ova – spermatozoa).
The development of cryobiology has helped to:
New method of cryopreservation: Vitrification
In recent years, great strides have been made in the field of cryobiology, with the greatest achievement being the possibility to cryopreserve male and female gametes (ova – spermatozoa), embryos and blastocysts.
The process of vitrification is a very successful freezing method and is achieved by using high concentrations of cryoprotective substances and the very rapid reduction of the temperature up to -196°C. The cooling rate of eggs – embryos reaches 20.000°C per minute, thus preventing the formation of intracellular water crystals which causes “damage” to cells.
The success rates of vitrification are very high compared to older methods of cryopreservation. It is now possible to freeze eggs with high survival, fertilization and implantation rates after thawing.
Lastly, success rates in frozen embryos are similar to those in fresh embryos.