If a woman chooses such a method as IVF as a method of treatment of infertility, then she will be first given hormone therapy in order to increase the production of good quality follicles by her body.
After this, the eggs get to the embryologist, who directly and will carry out fertilization.
As a rule, no more than 2-3 embryos are inserted into a woman's uterus. The rest, if desired, women can be subjected to cryopreservation or freezing. In case of an unsuccessful outcome of the first attempt of IVF, frozen embryos are used for the second or in the case if after the birth of the first child the woman wants to give birth to the second.
Transfer of embryos after cryopreservation
Cryopreservation is a well-established method of assisted reproductive technologies. The probability of pregnancy as a result of the transfer of embryos after cryopreservation is somewhat less than in the situation with freshly received embryos. But nevertheless, reproductive specialists recommend that their patients cryopreserve embryos left after the procedure, as the cycle of freezing and transferring cryopreserved embryos is much cheaper than a new cycle of IVF.
About 50% of embryos are well tolerated by freeze-thawing. At the same time, the risk of developing congenital pathologies in the fetus does not increase.
It is possible to freeze pronuclei, crushed embryo, blastocyst if they have a rather high quality for transferring
Embryos are mixed with a special medium that protects them from damage - a cryoprotectant. After that, they are placed in a plastic straw and cooled to -196 ° C. The metabolism of cells at this temperature is suspended, therefore it is possible to store embryos in this state for several decades.
The survival rate of embryos after defrosting is 75-80%. Therefore, to get 2-3 high-quality embryos for replanting into the uterus, it is required to unfreeze much more embryos.