On an equal basis with eggs and sperm, you can also freeze embryos obtained after IVF procedure. Compared to eggs,which are more fragile cells(it consists of 90% water), embryos are stronger and better tolerate the process of freezing and further thawing. The chances of pregnancy with “fresh” and frozen embryos are the same.
There are two methods of freezing:
1) slow freezing is practically not used today due to the high risk of cell damage, since ice crystals damage the cell structure and thus reduce its viability.
2) “Vitrification” or ultra-fast freezing. This method allows you to freeze the egg in the shortest possible time-instantly, with a very rapid decrease in the temperature ofliquid nitrogen (up to -196° C ). This substance is not poisonous and can’t harm the biomaterial. With this method, there is no clystalization stage, which guarantees the integrity of the cell (and, of course, the functions of the cell) during further defrosting.
Today only vitrification is mainly used. after slow cryopreservation the first healthy baby was born in 1984. In 1990, the first child was born after ultra-fast freezing (vitrification).
