How are the donor eggs frozen?
Once the eggs have been retrieved from the egg donor they are evaluated by an embryologist who selects only top quality, mature eggs for cryopreservation. Cryos cryopreserves them through vitrification.
This method prevents ice crystal formation which could potentially damage eggs, and allows for higher survival numbers and overall success rates when using frozen donor eggs. The donor eggs are then stored in liquid nitrogen tanks, where they saty frozen and therefore, alive, for up to 15 days.