The freezing of unfertilized eggs is no longer considered experimental. RMIA is now offering an ovarian reserve testing program to help determine if the egg freezing option is right for you.
Who Should Consider Egg Freezing (see criteria)
- Women diagnosed with cancer. Egg freezing offers a chance to preserve eggs prior to chemotherapy, surgery or radiation. Most of these treatments destroy the eggs and lead to infertility.
- Women who want to postpone pregnancy. With age, fertility declines, so freezing your eggs at an early reproductive age will best ensure your chance for a future pregnancy.
- Patients with ethical concerns about the disposition of frozen embryos. During the standard IVF process, patients will likely have extra embryos. The decision to fertilize only as many eggs as will be utilized in the IVF process and freezing the remaining unfertilized eggs is a solution for those with concerns about freezing embryos.
How Egg Freezing Works
Although sperm and embryos have proved easy to freeze, the egg is the largest cell in the human body and contains a large amount of water. When frozen, ice crystals form that can destroy the cell. Over the years we have learned that we must dehydrate the egg and replace the water with an “anti-freeze” prior to freezing in order to prevent ice crystal formation. We also learned that because the shell of the egg hardens when frozen, sperm must be injected with a needle to fertilize the egg using a standard technique known as ICSI (Intracytoplasmic Sperm Injection). Eggs are frozen using a flash-freezing process known as vitrification.
Egg Freezing Process
During the egg freezing process, the patient undergoes the same stimulation process as In Vitro Fertilization. The only difference is that following egg retrieval, the eggs are frozen for a period of time before they are thawed, fertilized and transferred to the uterus as embryos. It takes approximately 4-8 weeks to complete the egg freezing cycle. Some patients may require additional cycles. When the patient is ready to attempt pregnancy (this can be up to many years later), the eggs are thawed, injected with a single sperm to achieve fertilization, and transferred to the uterus as embryos.
Success rates are mostly determined by the age at time of freezing. Currently, in patients younger than 35, an egg survival rate of about 85% can be expected; from that point on, fertilization and pregnancy rates are similar to those observed during “fresh” cycles (see national statistics on the CDC website).