FER or FET

FET – Frozen Embryo Transfer

If, after the fertilization process in the laboratory and a possibly “fresh” trasnfer, there are “surplus” embryos of high quality, they can be frozen and stored in liquid nitrogen. The embryos can later be hatched and transferred.
This is possible both in a stimulated and in a natural cycle.

We only freeze embryos that have developed to the blastocyst stage.

Development of embryos

You can put the egg back in the embryo stage (day 2-3) or the blastocyst stage (day 5) – in other words, these are fertilized eggs in different developmental processes (cell division). As mentioned, only eggs in the blastocyst stage can be frozen.

Approximately 25% of the fertilized eggs develop into blastocysts. Whether the eggs can be cultured right up to day 5 depends on your age and the number of fertilized eggs.

For women who have only a few eggs of inferior quality, depositing the fertilized eggs on the second or third day may be preferable, as the eggs enter the natural uterine environment more quickly, where they can best survive. The excess eggs that develop into blastocysts can of course be frozen for up to 5 years or until the woman turns 46.

There is a small risk that a blastocyst will not survive thawing, but the vast majority make it through the process.

With us, this success rate is over 95%.