There are some rules for freezing the egg cell. For this purpose, egg cells should be ready for fertilization which is called M2. In M2, there is a diamond-shaped core called spindle containing 23 chromosomes. The other 23 chromosomes are located outside the cell. These are called polar body pole bodies
The most important issue in the process of freezing eggs, is the liquid contained in the cell. Although the egg cell is the largest cell in the body, most of it consists of water. In the freezing process, these liquid ice crystals become organelles that break down inside the cell and break down and break down the core contents of the cell during freezing. Therefore, it is necessary to remove the water inside the egg as much as possible before freezing. In the process of freezing the eggs, the water inside is taken out without damaging the cell with specially prepared liquids. Instead, a special liquid is introduced into the cell.
This special liquid is similar to antifreeze used in vehicles and is toxic to cells. This application will prevent damage caused by the crystallization of water in the freezing process, glassization ie vitrification will occur. Two different techniques are used in egg freezing process.
Slow freezing: The egg cell is frozen in a special freezing liquid and then cooled by slow cooling with a device. In this embodiment, the eggs which are slowly cooled down to -30 / -35 degrees are dipped in liquid nitrogen at -196 degrees. Although the slow freeze technique is successful in sperm and embryo freezing, it is not preferred because the egg freezing process is not successful enough.
The process of freezing eggs is mostly done by vitrification technique.
Fast freezing (vitrification-glassization): This technique, which has been used in the freezing of sperm and embryos in the past, has been developed and made suitable for freezing of eggs. In this technique, the egg cell is cooled from room temperature to -186 degrees. This method, which could not be applied in egg freezing process, has been developed and started to be done successfully with current applications. The cytoplasm structure of the unfertilized egg in the cytoplasm of the genetic material, the size of the egg was difficult to implement the process. However, with the introduction of new techniques and freezing solutions, vitrification technique has been made suitable for egg freezing. Therefore, high success rates have been achieved. Egg freezing process may use different protocols even if the clinics perform the same technique. But the result is the same.