The ability to freeze a human egg offers at least two important options for women: fertility preservation for women faced with potentially sterilizing therapies and individuals postponing childbearing, as well as couples requiring in vitro fertilization (IVF) who are ethically opposed to freezing (pre)embryos. Being able to freeze eggs also allows for the establishment of egg banks, greatly improving the efficiency and lowering costs for donor egg IVF.
We have been able to freeze (pre)embryos since the early 80’s, a technique that is routinely performed in most reproductive medicine programs. Freezing an unfertilized egg is much more difficult because of the large size and water content, i.e. as the egg cools ice crystals develop which can damage the working components known as organelles. When a (pre)embryo is frozen, the essential task of these organelles has already been performed.
The first pregnancy from a frozen egg was achieved by Dr. Chen in 1986. Following this pregnancy there were no other pregnancies until the early 90’s. With the abolishment of (pre)embryo freezing by the Italian government there was a resurgence in egg freezing technology. Dr. Borini and others refined the protocols for egg freezing, and with the advent of intracytoplasmic sperm injection (ICSI), whereby a single sperm could be injected into an egg the efficiency of egg freezing increased. Dr. Dunsong Yang, the head of embryology at the Florida Institute for Reproductive Medicine, was one of the early pioneers in refining the egg freezing protocol, greatly improving its efficiency.
The Florida Institute for Reproductive Medicine has one of the largest experiences with egg freezing in the nation with over 63 babies born, including the first baby born in the world to a cancer patient who froze her eggs prior to chemotherapy. Currently we are seeing pregnancy efficiencies of approximately 10 eggs equating with an ongoing pregnancy for egg donors 35 years or less and approximately 14 mature eggs for those 36-38 years of age. In general, we do not freeze eggs beyond 38 because of the high percentage of abnormal eggs. Our work on egg freezing has been chronicled in People, Self, Pink, Conceive, and Woman magazines as well as on CBS, NBC, BBC News, and the Today Show.
To date, in the world there are approximately 3,000 babies born from frozen eggs. Health data on these infants continues to be very reassuring. Until, however, high numbers of these children have reached adulthood and reproduced, the absolute safety of this technology cannot be asserted. For that reason egg cryopreservation is still recommended to be done under an IRB (institutional review board) approved protocol. At the Florida Institute for Reproductive Medicine we keep yearly surveys of our cryo egg births through annual questionnaires to parents and pediatricians. Costs for egg freezing at the Florida Institute for Reproductive Medicine mimic those of an IVF cycle, i.e. approximately $10,500.
We will store eggs at no charge for a period of five years, after that time there is an annual storage fee of $400. For our cancer patients seeking fertility preservation, we have been able to get medicines donated by the Ferring drug company, saving patients approximately $3500. The longest an individual has stored eggs to date and had a successful pregnancy is 6 ½ years. We do not believe there likely is a shelf life to frozen eggs.