Benefits of Frozen Embryo Transfer (FET)

An embryo is formed when the egg is fertilized by the sperm. The embryos created in in vitro fertilisation (IVF) can be transferred back to the woman’s uterus in 2 ways:

1. Fresh Embryo Transfer (ET)
   Fresh ET is the transfer of embryos that are formed 3 or 5 days after oocyte pick up (OPU) during fresh IVF cycle.
2. Frozen Embryo Transfer (FET)
   FET uses frozen embryos for transfer. Similar to fresh cycle, fertilised embryos are cultured until day 3 or day 5. Depending on the quality of the embryo, slow developing embryos may need to be cultured to day 6 or day 7 in order to form blastocysts. Those embryos that the embryologists deemed as freezable grade are frozen. This would mean that embryos which are able to survive the freezing and thawing process will be frozen. Poor quality embryos will not survive the harsh freezing and thawing process. All freezable grade embryos are frozen and stored for future implantations.

What is FET?

Frozen Embryo Transfer (FET) as its name suggests, is the transfer of 1 or 2 embryos that were frozen during in IVF to the women’s uterus after a period of preparation of the uterus. Frozen embryos are thawed 2-3 hours prior to the procedure. If implantation takes place, it would lead to a pregnancy.

The benefits of FET:

• In certain situation, it gives time for the uterus environment to return to normal after IVF medications.
• It allows for pre-implantation test (PGT) for couples with history of genetic diseases. Under Singapore’s MOH regulations, only clinically eligible couples are allowed to do PGT. Please click here for more information.
• It reduces the risk of ovarian hyperstimulation syndrome (OHSS) during embryo transfer, especially in cases with high numbers of eggs retrieved.
• It can be scheduled on an elective basis.
• It allows for synchronisation between slow growing embryos and the womb environment.

For more information on how to prepare for an embryo transfer, please click here.