HOW ARE EGGS FROZEN?
Given the current buzz you might think that egg freezing is a new fertility technology. Not the case…
Egg freezing has been around for over thirty years. In fact, the first recorded birth from a frozen egg, using the “slow freezing” method was in 1986.
Slow freezing was fraught with problems. Delicate human eggs have a very high water content level so freezing them without causing ice crystal formations is tricky.
Everything changed in 2005 with vitrification. The new ultra-fast freezing method revolutionized the way human eggs are frozen.
SLOW FREEZING VS. VITRIFICATION
EGG VITRIFICATION PROCESS
The verb ‘vitrify’ means to transform into a glass or a glass-like substance. The two primary difference between vitrification and the slow freeze method are:
1) Higher levels of cryoprotectants are used (anti-freeze)
2) The freezing process is significantly faster
So, how does vitrification really work?
First, eggs are place into a bath of cryoprotectant and sucrose to begin the dehydration process.
Eggs are then transfered to a highly concentrated cryoprotectant solution for one minute.
Next, eggs are loaded into pipettes or tiny straws. Eggs are divided into several pipettes for damage control.
Pipettes are plunged into liquid nitrogen. Eggs will move from room temperature to -196°C in a matter of seconds.