Egg Freezing by Vitrification
For more than a quarter century, medical scientists have attempted to defy the biological clock by freezing a woman’s eggs to preserve her fertility. Until recently, almost all such efforts have yielded very poor results. This is why, since the birth of the 1st “frozen egg baby” in the mid 1980’s, fewer than 1500 such births have been reported worldwide. Compare this to the more than 3-4 million IVF babies born in the same time period and the approximately 25,000 IVF births per year resulting from frozen embryos.
Harvesting eggs for freezing typically involves giving a woman fertility drugs to stimulate her ovaries to produce multiple eggs, and then harvesting those eggs from her ovaries using ultrasound guided needle aspiration. Typically, it takes at least one cycle of fertility drug administration to harvest about 12 to 15 eggs.
Until quite recently, the reported statistical chance of each frozen and thawed egg ultimately resulting in a baby has been under 5%. A key reason for this is that traditional freezing techniques are very damaging to the egg. This is because eggs contain a lot of water and, as a result, ice crystals can form that may damage their structure to the point that a high percentage do not survive the freezing and/or thawing process. Those that do are usually so compromised that they are rendered “incompetent”.
The recent introduction of a new freezing method called vitrification eliminates this effect, because it freezes the eggs so fast (about 600 times faster than older methods), that ice crystals will not form. Vitrification uses a cryoprotectant formula that helps dehydrate the eggs so that they can be safely frozen without forming damaging ice crystals. When, at a later date the woman is ready to use her eggs, a thawing formulation reverses the process, rehydrating the eggs back to their original state. Thus, vitrification has opened the door to safe freezing and banking of eggs over an indefinite period of time.