Body cells (somatic cells) can be preserved for several years by freezing and storing them in liquid nitrogen.
The low temperatures ensure that biological activities such as cell death and DNA degeneration stop and the cell constitution remains unchanged. The frozen eggs or sperm are therefore as vital as before after thawing.
Cryopreservation can be used to store cells and tissue over long periods of time for later use @ sola_sola /AdobeStock
The problem with cryopreservation is the formation of ice crystals during the process. These lead to cell damage and cell death. For this reason, experts use cryoprotective solutions to minimize the risk of ice crystals.
This option is also known as vitrification and is an alternative to "slow freezing". Here, the cells receive a high concentration of cryoprotectants. These remove liquid and transform the cells into a glass-like state. In this way, experts avoid the formation of ice crystals.
Fertilizable male sperm and female egg cells are necessary for pregnancy. If one of the two germ cells is non-functional, the fusion fails so that no embryo can develop.
If infertility is imminent or foreseeable, cryopreservation can be used to preserve fertile egg or sperm cells. Viable egg or sperm cells are needed for various reasons.
The reasons for women
Infertility sets in naturally during the menopause. The perimenopause, the phase shortly before menstruation stops, occurs on average at 47.5 years of age
- Women'spersonal decisions, such as career planning and contraception, or stress also play a role in individual family planning.
- For many women, the first pregnancy therefore occurs at increasingly later stages of life. The number and quality of eggs steadily decline from around the age of 35.
- In order to have eggs that can be fertilized safely available later, women can have eggs retrieved and stored(social freezing).
The reasons for men
- Premature infertility in men occurs, for example, due to increased alcohol or nicotine consumption as well as severe narrowing of the vas deferens.
- Cancers, such as testicular cancer, are treated by removing the diseased testicles. In addition, certain chemotherapeutic agents are used for numerous cancers, which can lead to inability to conceive.
Cryopreservation is a procedure used to freeze male or female germ cells or already fertilized eggs.
It is now also possible to remove fertile ovarian tissue and implant it later. In this way, fertility can be preserved after chemotherapy, for example.
In a later "cryo-cycle", doctors can thaw the cryopreserved cells and use them for artificial insemination.
Here, experts continue to cultivate the fertilized egg cells until the embryonic stage. They then insert the egg cell into the woman's uterus (embryo transfer).
Not all cryopreserved egg cells are suitable for transfer @ Iryna /AdobeStock
In the case of germ cells (unfertilized), you must first fertilize the eggs with the sperm in an IVF or ICSI procedure.
While the cryopreservation of male sperm is relatively simple, the preservation of female eggs is more difficult. The reason for this is the water content of the egg cell.
Pregnancy rates after the fertilization of cryopreserved unfertilized eggs are lower than when using freshly retrieved eggs. However, the vitrification process has significantly improved the results.
Research into the cryopreservation of germ cells and fertilized eggs is well advanced. There are many centers and clinics in Germany that offer cryopreservation and promise good results.
Furthermore, no serious adverse effects of cryopreservation are known.
The method helps couples in the early stages of family planning and allows flexibility in terms of time.
Health insurance companies do not cover the costs of germ cell storage through cryopreservation. Couples must therefore cover the costs themselves.
The cryopreservation of germ cells and fertilized eggs is legal in Germany. If you have germ cells thawed and used for artificial insemination, you must submit a written declaration of consent.
In the case of fertilized eggs, a written declaration of consent must be provided by both the woman and the man.
