Frozen/thawed fertilized oocyte(s) may be used for embryo transfer. This requires the thawing of a number of the cryopreserved fertilized oocytes, monitoring them to ensure they have survived and progressed to embryo stage and then replacing them into the uterus.

Success rates with frozen cycles are slightly lower than those with fresh cycles as, on average, 70% of the frozen fertilised eggs/embryos survive the preservation process. Some cycles may be cancelled if no embryos survive the process.