Cryopreservation and vitrification

Cryopreservation is the collective name for freezing surplus quality embryos for future use. Thus, frozen embryos can be thawed and then transferred into the uterus. Frozen embryos can be kept for several decades.

Vitrification is an advanced cryopreservation technique that is currently used in quality clinics. Unlike previously used slow freezing, the goal was to control the production of ice crystals in order to minimize damaging the cell. No ice crystals are produced during vitrification. After heating the cells are in excellent condition and results achieved are much better than when using older methods.

Why we freeze embryos

Thanks to a very high success rate we always transfer only one embryo. This is mainly an effort to reduce the risk of multiple pregnancies. Excess embryos that meet the quality requirements can be frozen for later use in frozen embryo transfers (FET).

Frozen embryo transfers

Frozen embryo transfers are embryo transfers of thawed embryos. It is not only used for surplus embryos, but also for those examined by PGD or PGS.

Success rate

The success rate of FET is as high as for fresh transfers. Sometimes it may even be slightly higher, because the cryopreservation is already a form of selection of an appropriate and quality embryo. For most patients frozen embryo transfers occur in the native cycle without hormonal preparation.