There are many reasons why you might want to consider fertility preservation. Perhaps you haven’t yet met the person you want to have a family with. Or you’re focused on another important part of your life, like your education or career. Maybe you’re undergoing medical treatments or being deployed overseas, and you want peace of mind knowing the option is available if needed. Whatever your reason, freezing healthy eggs, embryos, or sperm—called cryopreservation—may be a good option if you’re not ready for children now, but may want them in the future.
How does cryopreservation work?
In cryopreservation, very low temperatures are used to preserve the living cells that make up eggs, embryos, and sperm. Your cells will be mixed with a special “anti-freeze” solution, cooled, and stored in liquid nitrogen. When they are ready to be used, the cells will be warmed.
The cryopreservation process used to freeze eggs, embryos, and sperm is usually one of the following.
During slow freezing, the temperature around the cells is gradually reduced. Although this method has been around for a long time, slow freezing leaves more time for harmful ice crystals to form, which can cause critical damage to the cells. Because of this, not all cells will survive the slow-freezing process.
In vitrification, or flash freezing, the temperature around cells drops rapidly. This solidifies cells into a glass-like state and avoids the risk of ice crystals forming, protecting them from damage.
Vitrification is a newer technique. It improves the survival of thawed embryos when compared to slow freezing, according to clinical trials:
Adapted from Valojerdi M, et al. J Assist Reprod Genet. 2009;26:347-354.
Different labs may use different methods for freezing eggs, embryos, and sperm. Before choosing a facility, ask about their cryopreservation technology, processes, and success rates. This customizable tool can help organize your thoughts and guide your discussion.
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