Embryos that are not transferred to the uterus are used for freezing. It is strongly recommended that surplus good quality embryos be frozen after the embryo transfer is complete. The process is also called cryopreserved(cryopreservation) Embryos can be frozen for up to 10 years and these can be replaced in a future cycle without the woman having to undergo the same drug treatment or IVF.
Frozen embryo transfer (FET) consists thawing of the frozen embryos and replacing them in the uterine cavity. The replacement can be carried in a natural cycle if the patient has a regular menstrual cycle. Almost 90% of all frozen embryos survive the thawing process. Some couples may even have all of their embryos survive in good condition; others may not have the same survival rate. This procedure allows an increase in the pregnancy rate while reducing the number of times the ovaries must undergo stimulation. It also lessens the number of hospital attendances for egg pick up procedures. The cost of achieving a pregnancy may also be reduced with the help of embryo freezing method. The only disadvantage may be deciding what to do with those embryos in storage after you have become pregnant.