How Egg Freezing is done
Egg freezing in the past was mostly used as an experimental method of preserving fertility. Pregnancy rates with egg freezing were less then stellar. Today a new method of freezing is used called Vitrification. Previous "slow freeze" methods caused the fluid inside the egg to crystallize. This crystallization caused less then optimal environment for future thawing and fertilizing. With the modern Vitrification method the egg is frozen almost instantly with liquid nitrogen; thereby minimizing crystallization. With Vitrification success of thawing and fertilizing the egg has increased. At American Reproductive Centers we use Vitrification as the preferred method for freezing.
For eggs to be retrieved for freezing the patient must undergo a treatment similar to IVF. To stimulate the ovary the patient is given hormonal medication (FSH analogues). This medication allows the ovary to produce more then the usual 1 egg. The patient is then monitored regularly to evaluate how she is respond to the medication. This treatment typically lasts for 10-12 days. Once the eggs are determined to be ready for retrieval the patient undergoes a procedure called an "egg retrieval". Once the eggs are retrieved the embryologist evaluates the eggs for maturity. All mature eggs are then frozen using the method described above.