Frozen embryo transfer

Frozen Embryo Transfer
Cryopreservation (freezing) is a gentle way of cryopreserving embryos in special cryocontainers with liquid nitrogen at tthe temperature of -196 ° C.
The center for assisted reproduction of Sanatorium Helios has been using vitrification methods for freezing embryos since 2007. At present, thanks to collaboration with Genea World Leading Fertility we are currently using fourth-generation vitrification methods. In our IVF Laboratory we use GAVI vitrification machine – transfers of embryos frozen on GAVI are more successful than the previous method and the pregnancies better prosper.
In long terms we achieve high succes rates with frozen embryo transfers, even higher than with fresh embryo transfers. Concerning frozen embryo transfers, we also introduce only one embryo so as to increase your chances of getting pregnant!

This fast freezing method – vitrification avoids the extensive damage to embryo tissues, it avoids the formation of ice crystals.

When are embryos are frozen (vitrified)?

– When there is more than one embryo of a suitable quality retrieved after an IVF cycle or when we prefer a frozen embryo transfer in the natural cycle to a fresh embryo transfer.
– When the preimplantation genetic testing (PGT) of the embryo is carried out.
– If fresh transfer is not recommended for health reasons (OHSS, polyp, etc.).
– You can even store your embryos before radiotherapy or chemotherapy, which could damage germ cells and subsequently cause infertility issues.
Before your frozen embryo transfer you need to contact our IVF coordinators to schedule for an ultrasound check up, which is usually carried out between 12th to 14th day of your cycle cycle. Optimally call the co-ordinators at the beginning of the cycle. If the doctor finds out that it is suitable to perform the frozen embryo transfer, then the term of the frozen embryo transfer is planned – according to the individual situation.
Based on our long-term experience and current scientific knowledge, we prefer transferring the embryo in a natural cycle. Therefore, there are lots of transfers that could be performed as “fresh” , but instead they are performed in one of the other cycles as frozen embryo transfers.

On the chart above, there is a comparison of the success rate of fresh tranfers and 1st frozen embryo transfers – G+ is a positive pregnancy test, ASP+ clinical pregnancy
demonstrated by fetal heartbeat, P+ delivery.

There is evidently higher success rate in vitrified embryo transfers compared to fresh transfers in cycles after stimulation.Higher success rates of pregnancy are due to the natural cycle in which the embryos are transferred as frozen embryos, and also in this group it is partly reflected the higher success rates of transfers of the embryos with the correct genetic finding.

Would you like to learn more? Make an appointment for a consultation with our fertility experts.
Call 549 523 258, e-mail us at, or use the contact form below. We look forward to helping you.