Frozen embryo transfer

Cryopreservation (freezing) is a gentle way of cryopreserving embryos in special cryocontainers with liquid nitrogen at the temperature of -196 ° C.

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 of vitrification methods.

We use the GAVI vitrification machine in our IVF Laboratory – GAVI frozen embryo transfers are more successful than the previous method and pregnancy is better.

This rapid freezing method – vitrification – allows the water inside and surrounding the embryo to instantaneously super cool into a solid state with no ice crystal formation at all.

When the embryos go frozen (vitrified)?

  • if there is more than one embryo of suitable quality retrieved after an IVF cycle
  • if PGT tests are carried out
  • If fresh transfer is not recommended because of health reasons (OHSS, polyp, etc.)
  • You can even store your embryos before radiotherapy or chemotherapy, which can damage germ cells and subsequently it can cause fertility disorders.

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 in at the beginning of the cycle. If the doctor finds that it is suitable to perform the FET, it usually takes place on the 19th day of your cycle (depending on the length of the cycle).

  • Number of FETs has risen significantly, compared to fresh transfers after the hstimulation. Higher percentage of frozen embryo transfers is to a certain extent given to the fact that all embryos after PGT after biopsy are frozen and transferred in later cycles. Impact on the success of frozen embryo transfers is potentiated by natural-transfers in unstimulated cycles.
  • Given that prolonged cultivation, examination PGT on blastocysts and their subsequent their vitrification, and transfer of one embryo examined by PGT methods in a natural cycle, it is in our opinion and experience currently the most appropriate procedure IVF. Therefore we perform increasing numbers of PGT frozen embryo transfers cycles with a very high success rates.

Would you like to learn more? Make an appointment for a consultation with our fertility specialists.

Call +420 549 523 258, e-mail us at, or use the contact form below. We look forward to helping you.

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.

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