What is Embryo Cryopreservation?
Cryopreservation allows us to preserve embryos obtained during an IVF treatment for later use. After incubation in cryoprotectants, vitrification occurs to protect them from the effects of water crystallization during the freezing process, the embryos are rapidly frozen and kept at very low temperatures (-196oC) until use. Viability of these embryos can thereby be preserved for years.
Cryopreservation of surplus embryos can be particularly useful in some situations:
- To possibly improve pregnancy outcomes. By delaying a fresh transfer, we can create a more natural physiologic uterine environment
- To avoid possible medical risks of ovarian hyper-stimulation syndrome (OHSS)
- For a second pregnancy from the same IVF treatment
- When, for any reason, a fresh embryo transfer is not an option
Odds of Success
It is noteworthy that embryo cryopreservation is particularly efficient (survival rates of about 95-97%) when the embryos are growing well. However, not every embryo is a good candidate for cryopreservation. As a result, the success of the procedure is intimately bounded to the embryo selection before freezing.