Cryopreservation is a difficult and still not efficient method for preserving eggs

One of the leading Russian publications «MedDaily» has recently left my comment, dedicated to the cryopreservation of oocytes. I believe that it could be pretty interesting for those who are currently undergoing or intend to undergo the procedure of IVF:

By Sergei Lebedev | Sweetchild Group President, Member of the European Society of Human Reproduction and Embryology tells whether the procedure of eggs’ cryopreservation during the IVF has a negative impact on the child.

"If we talk about the cryopreservation of female genetic material (oocytes), then I will say that along with its undeniable advantages, this method has two major disadvantages. First of all, inconvenience for a woman who decides to use this method (I mean stimulation of superovulation with all its known consequences. The second is a lower reliability of this method in comparison with cryopreservation of sperm or embryos.



Technically cryopreservation of oocytes is much more difficult than cryopreservation of sperm / embryo, because the egg cell contains water, which literally expands upon freezing and breaks an egg. To avoid this, they use procedure of vitrification (simply put, drying). Technology of "eggs’ freezing" is quite complicated, so at the beginning its efficiency was very low. However, in recent years this method has been largely worked out, and the efficiency of female genetic material’s cryopreservation has increased to such an extent that from just theoretical, experimental method it moved to the category of widely used.

However, the efficiency of oocyte cryopreservation (which is defined as the percentage of successfully unfrozen oocytes) is still less than that for embryos and sperm. The success of the procedure largely depends on the qualifications of the doctor who conducts the cryopreservation. In my opinion, in Russia, for example, there are dozen of such experts. At the same time, cryopreservation of sperm or embryos is being done at a high level in almost every clinic. So if there is an opportunity, I would still recommend to freeze embryos as the chances of success are much greater.

As for the harm to an egg, the answer is twofold here. On the one hand, as I’ve already said, cryopreservation does not always go smoothly. On the other hand, if an egg is "back to life", you shouldn’t be afraid that there are some “hidden" disruptions, which may lead to negative consequences for the unborn child. This mechanism works in the "on-off" mode, so either the genetic material "comes alive" and then it’s all right with it or it’s not back to life at all, there are no intermediate options.