Since the vitrification technique was introduced in the laboratories, the survival rate of embryos is much higher than with the former techniques of slow freezing. Additionally, the fact that we are now trans-freezing mostly blastocysts is another factor that has significantly contributed to increasing the survival rate of these procedures. In our laboratory, we consider that at least 98.5% of the embryos should survive the thawing process.
The percentage of embryos that survive freezing depends on the quality of the embryos, first, and second, in the laboratory. In our laboratory, the survival rate is around 90% which is quite a high rate because we classify the embryos, and we are quite strict in doing so. If we are talking about laboratories that do not classify the embryos in that way and they are not so strict in freezing just the good quality or at least optimal quality embryos, the rate of survival could also be decreasing.
