Frozen Embryo Replacement (FER)
FER is short for Frozen Embryo Replacement. An embryo is an egg that is fertilized after being thawed as a frozen egg. This embryo was extracted and fertilized earlier in a “fresh” attempt, also known as a trial attempt, and is used in a later cycle.
Where do the frozen embryos come from?
The frozen embryos we thaw and put back into FER-treatment are embryos the woman previously had frozen after a fresh attempt where several eggs are stimulated and extracted, fertilized in a test tube, and allowed a few days to evolve and mature to the blastocyst stage. So, FER-treatment is not a treatment you can start right away. You must first complete a fresh trial.
How does a FER treatment take place?
During in vitro fertilization (IVF) we often get more than enough good embryos to put back. These we can freeze and put back at a later time in a later cycle. The benefit of FER is that a woman avoids going through the whole treatment of stimulation and egg extraction again. The thawed embryo is inserted during a natural or lightly stimulated cycle in a simple, painless procedure that is over in a matter of minutes.
The frozen embryos have to be used before the woman is 46 years old. Previously the frozen embryos could only be stored for a maximum of five years, but with the changes in the Biotechnology law from the July 1. 2020, this deadline no longer exists. The embryos can only be assigned to the woman they came from.