Cryopreservation
and Cryotransfer
The freezing of sperm, embryos or eggs is known as cryopreservation.
The freezing of sperm, embryos or eggs is known as cryopreservation.
Cryopreservation is a common method used in fertility treatment. In Germany (country-specific), several different materials can be frozen:
With unfertilised eggs, there is still a relatively high risk that they can be damaged during the cryopreservation process. Unfertilised eggs have a much greater sensitivity to the freezing process due to their higher water content (compared to fertilised eggs). Water crystals that form during the freezing process can therefore cause more damage. Nevertheless, the frozen, unfertilised eggs are still valuable and can be used to conceive children in the future.
By using computer-assisted temperature programs that control the freezing process and special cryopreservation procedures in which cells are mixed with a membrane-protecting medium (the cryoprotectant), the cells are put in a state that ensures that they can be stored over long periods (years) without impairing their viability.
In Germany, under the Embryo Protection Law, embryos may be frozen only in exceptional cases.
As part of infertility treatment, cryopreservation of sperm may be necessary due to the prolonged absence of the partner, a health condition, or difficulty on the part of the man to provide sperm on demand (psychological impotence).
Testicular tissue obtained in a biopsy (see TESE) can be frozen for later sperm retrieval. This allows for hormonal stimulation of the ovaries in the woman without time restraints. In addition, multiple biopsy samples can be individually frozen for several ICSI attempts.
Thanks to state-of-the-art cryopreparation techniques, it is possible to carefully freeze tissue without impairing the physiology of the cells. The thawed, intact ovarian tissue can then be re-implanted after several years of cryopreservation (autotransplantation). It is also possible to remove the eggs that have matured in the ovarian tissue from the cryopreserved tissue at a later date and use these for artificial insemination.
If you would like to know more about cryopreservation and cryotransfer, have a question or would like to make an appointment at your local fertility centre, please contact us. We will get in touch with you as soon as possible.
Once a couple has a desire to use a frozen fertilised egg to get pregnant, this egg can be further cultivated and transferred to the uterus. This is referred to as cryotransfer. Unfertilised eggs that have been frozen are fertilised in advance by an intracytoplasmic sperm injection.
The cryotransfer can be carried out at optimal cycle conditions without any hormonal support. Another possibility is to assist the build-up of the lining of the uterus with oestrogen and to optimally prepare it for the implantation of the egg. The doctor can measure the thickness of the lining of the uterus with an ultrasound scan. Once it is thick enough, ovulation is stimulated by administering progesterone. This changes the structure of the lining, preparing it to receive embryos. The third option is hormonal stimulation with clomiphene or FSH to support follicle maturation prior to embryo transfer. The doctor can then insert the embryo(s) into the uterus using a soft catheter.
Cryopreservation has been used for many years, and most studies show no adverse effects. However, an individual consultation is always included as part of the treatment.
Health insurance companies in Germany do not usually pay for the cost of cryopreservation – even if it is carried out due to the treatment of a serious illness.
Get all the answers to your questions in an initial consultation with our fertility experts at the fertility clinic near you.