We have been freezing eggs since 2006.
At Pacific Fertility Center, we have been freezing eggs since 2006 using a process called vitrification. This is an ultra-rapid freezing technique that works well for both egg and embryo preservation.
The eggs are exposed briefly to cryoprotectants, which remove water from the cells. The removal of cellular water is a critical part of any freezing procedure. It prevents formation of ice crystals and allows cells to survive the vitrification process, when the eggs are frozen in liquid nitrogen at -196°C.
Eggs can be stored indefinitely without any obvious loss of viability. When they are eventually warmed, water is allowed back into the cells. This restores the pre-vitrification state and washes away any traces of cryoprotectants. The eggs are then fertilized using intracytoplasmic sperm injection (ICSI) and the embryos develop normally.