Cryopreservation
For many years freezing semen samples have been a possibility.Human semen was first successfully cryopreserved, with subsequent pregnancies and births in 1953.
Nowadays freezing semen and testicular tissue samples are a routine procedure in the embryological laboratory. The samples can be frozen before a treatment cycle to be thawed when needed.
Equally important is the cryopreservation of embryos. If a sufficient number embryos are available, then one option is to freeze the surplus (spare) embryos for possible use at a future date.
Usually embryos are frozen on the first day after fertilization, on the second day (4 cell stage) or at the stage of blastocyst formation (5/6 days after fertilization).
Cryopreservation gives us the possibility to store the embryos that will not be transferred in the present cycle for a later date without the cost and inconvenience of a stimulated IVF cycle. Also, in rare occasions when we wish to delay the transfer to avoid the risk of ovarian hyperstimulation syndrome or when we wish to wait for a time when endometrial receptivity will give us a better chance of pregnancy.
Storage is in liquid nitrogen at –196*C.
Although there is no theoretical time limit of storage you will be asked to sign a consent form according to the IVF center policy / IVF legislation ascertaining to the length of time allowed for Cryopreservation.
If the couple at a future date wishes to transfer their embryos/semen to another IVF center this is of course a possibility by transporting their samples in miniature liquid nitrogen containers can “Dry Shippers”.
read more about the technique Vitrification
