Cryopreservation – freezing egg cells, sperm cells and embryos
Hormonal stimulation of the ovaries, for example in preparation for in vitro fertilization, generally enables several egg cells to be collected. IVF or ICSI treatment procedures also tend to result in several embryos. Since we only return one or at most two embryos to the womb (embryo transfer), there are usually spare embryos left after a cycle of stimulation.
These need not be discarded, but can instead be deep frozen and stored in liquid nitrogen, then thawed at a later stage and used for a subsequent treatment. Where this type of “cryo-cycle” process is used, there is no need for stimulation of the ovaries and collection of egg cells.
Freezing and thawing are delicate procedures that are of vital importance for the survival of the embryos. At Döbling Fertility Center cryopreservation is carried out by vitrification, which is currently the most successful method available. Using this method we achieve pregnancy rates close to those achieved with egg cell extraction cycles.
As well as freezing embryos, we can also freeze sperm cells and egg cells – primarily for medical reasons. Freezing of egg cells for the purpose of “egg cell banking,” in order to extend fertility to a later age, is currently subject to strict legal constraints in Austria.