Advances in egg freezing:
Vitrification technology and our ongoing IVF clinical trial to advance our ability to help preserve fertility
Embryo freezing and the transfer of these frozen embryos months or even years later has become almost routine as a tool to manage infertility. The first calf (Frostie) from a frozen embryo was born in England in 1973 and the first human baby from a frozen embryo in Australia followed about 10 years later in 1983. Today, approximately 20% (~20,000 babies per year) of all IVF babies born in the United States are the result of frozen-thawed embryos.
However, the ability to freeze an unfertilized egg proved to be much more difficult. If successful, egg freezing allows the preservation of eggs and, subsequently, potential fertility preservation for patients facing imminent life-saving cancer treatment. Furthermore, this technology can rescue eggs during an IVF cycle where sperm cannot be obtained in a timely manner. If able to successfully bank donor eggs, the cost of donor-oocyte cycles can be reduced significantly, since eggs from a single donor can now be shared between two or more recipients. Eggs age with their owner and; therefore, fertility significantly decreases with patient age, starting as early as age 34. Banking younger eggs for later use may be an acceptable approach to increase the potential for future child bearing.
The first baby from a frozen egg was born in 1986 in Australia using conventional slow freezing techniques. Routine egg freezing never became feasible because of very low success rates, compared with that of routine IVF or even if compared with the use of frozen embryos (a pregnancy rate of only about 1.5% per frozen egg). Early in the 2000’s a new technique made its appearance - vitrification. Vitrification differs from conventional slow freezing by being an ultra-rapid cryopreservation method, using high concentrations of three or more cryoprotectants, and very high cooling rates (thousands of degrees per second), thereby preventing any ice formation inside or around the egg. Vitrified eggs result in significantly improved and consistent post-freezing survival. Indications are that pregnancy rates obtained from vitrified eggs are now much closer to those obtained from frozen or even fresh embryos.
Despite the promise of egg vitrification, very few infertility programs in the world currently offers this as a clinical service to their patients. This is partly due to a lack of confidence, experience and the significant time lag between vitrifying the egg and knowing the outcome. Appreciating the future need and promise of egg vitrification, the Frisco Institute of Reproductive Medicine very recently received Institutional Review Board (IRB) approval to conduct a formal patient-compensated clinical trial on egg vitrification starting in February, 2012. Infertility patients meeting criteria (≤37 years old, not overly overweight, able to produce a reasonable number of eggs, and having a medical reason for in vitro fertilization) may choose to participate in this study at the Frisco Institute for Reproductive Medicine. During this study, half of the eggs will be vitrified (frozen), warmed back up (thawed) a few minutes later, and then fertilized with the other half of the eggs. All other aspects of the IVF treatment plan remains as determined by the doctor. Patients participating in this study receive significant financial support for their willingness to advance knowledge in this important area of infertility treatment. A total of 20 slots are available. More information about this study can be obtained at www.clinicaltrials.gov or by contacting the Frisco Institute for Reproductive Medicine.
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