Cryopreservation of various tissues
Deep-freezing = Cryopreservation
It is possible to cryopreserve:
- Extracted testicular or ovarian tissue
- Eggs cells and embryos
Cryopreservation is the freezing of sperm, testicular or ovarian tissue, eggs cells or embryos and the storage in liquid nitrogen at -190 °C. Using this method, the longevity of tissue, sperm, eggs cells and embryos can be extended by several years.
Testicular tissue or sperm that have been gained through TESA/MESA can be cryopreserved and then used for a future assisted fertilization treatment.
The freezing of sperm makes sense when testicular surgery, chemotherapy or radiotherapy are planned due to disease and are expected to limit future fertility.
If during IVF or ICSI treatment more eggs are fertilised than required for embryo transfer, the surplus eggs can be cryopreserved in the eight-cell or blastocyst stage.
If necessary the embryos can be later defrosted and transferred into the uterine cavity to enable pregnancy without further IVF or ICSI therapy. This procedure is called cryocycle.
Eggs cells and ovarian tissue can be cryopreserved. This is in particularly relevant for women whose fertility is threatened by chemotherapy or radiotherapy.
Thanks to egg freezing, if there is a medical reason, women have the opportunity to store their egg cells for a subsequent pregnancy.
Cryopreservation of oocytes in special cases
Thinking ahead gives more family planning options. The freezing of eggs increases a woman's chances of having children later in life and in cases where she suffers cancer.
The cryo-preservation of sperm has already been practised successfully for over 50 years. The fragile egg, however, has delicate inner structures and a cytoskeleton that is very vulnerable to the formation of ice crystals. Research has now managed to open another door in reproductive medicine by successfully freezing and thawing eggs.
It is usually difficult for women aged 40 and over to become pregnant the natural way. Furthermore, late pregnancies bear an increased risk of miscarriage and genetic abnormalities.The timely freezing of eggs is also a practical remedy for many problems. Young single women about to receive chemotherapy choose cryopreservation to retain their chances of having a biological child.