Embryo Cryopreservation (Freezing)

In Vitro Fertilization Program

If you have embryos cryopreserved during a treatment cycle, you may have a portion or all of these embryos thawed and transferred for subsequent treatment cycles.  The IVF-RT Laboratory free of charge will store frozen embryos for two years.  Should you consent to a longer storage period, a fee will be charged for subsequent years of storage.

The standard frozen embryo transfer cycle promotes creation of the ideal cycle with estrogen and progesterone tablets.  The goal is to allow transfer to a uterus synchronized with the age of the embryos.  The date of embryo transfer is determined several weeks in advance.

Embryos are thawed at a specific time during your hormone replacement cycle, in accordance with the embryo's age at freezing.  Following thawing, the embryos are incubated for two to 96 hours in the laboratory depending on the age of the embryo at freezing and whether transfer will be to the fallopian tube or uterus.

Approximately 85 percent of the embryos frozen at the pronuclear stage survive freezing and thawing.  The cryosurvival rate for blastocysts is approximately 50 percent.  The transfer procedure for frozen embryos is identical to that for fresh embryos. 

The expected rate of live births per frozen embryo transfer is somewhat lower than that of patients who have had fresh embryos transferred.  While the investment of time, expense and physical risk is lower with a frozen cycle, the emotional investment and risk of disappointment is comparable to that of a fresh transfer cycle.