Understanding Infertility

If your fresh IVF cycle has remaining embryos, your cycle was a “freeze-all” cycle, or you are freezing eggs or sperm, cryopreservation will be a necessity.

Embryos can be frozen at day 2-6, but usually only good embryos that can survive the dethawing process will be frozen. Embryos are kept at -320F (-196C) in liquid nitrogen. Usually 60-90% of embryos survive thaw when it is time to transfer – each clinic has different survival rates.[1]

Frozen sperm and embryos are easy to dethaw, but frozen eggs prove more of an issue. In the past, freezing eggs was difficult due to egg death or lack of fertilization. However, in recent years, success has risen to be similar to using fresh eggs.[2][3] This can be useful for women who want to preserve their fertility for later years.