Blastocyst culture

When we talk about blastocyst culture, we refer to the time an embryo spends in the laboratory. This is for at least 5 days, in which the embryo goes from having 1 or 2 cells to becoming an embryo of more than 150 cells and ready to be transferred. 

In fact, in nature, this is just the time when an embryo implants in the woman’s uterus. Therefore, in the laboratory, the embryo is expected to reach the blastocyst stage in order to be transferred and/or vitrified for future transfers. 

It should always be kept in mind that not all embryos develop from zygote to blastocyst. That is, from day +1 to day +5 of fertilization. This is because day +4 of development, morula stage, is decisive at the time of culture. In case of failure to develop, this is known as embryo arrest.

For many years, day +3 embryos were used for transfer. In fact, many clinics continue to do so. However, waiting until day +5 at the blastocyst stage is much better because it balances out. Just as in nature, this is the time of full development of the embryo to be implanted.

Embryo cultures develop in a favorable environment for their development. This increases the probability of intrauterine implantation. Of course, this will depend on each patient’s particular case.  

Therefore, by combining the culture with the Time Lapse incubator, the fertilization of the embryos is better controlled and this helps biologists to choose the ideal embryo for transfer. 

Frequently asked questions

  • Why don’t all embryos reach the blastocyst stage? It can be due to several reasons: the quality of the sperm or egg that is fertilized, the quality of the embryo, an environment that is unfriendly to development, or simply natural selection.
  • What are the advantages of blastocyst culture? Among the advantages are: selection of embryos suitable for transfer, increased chances of implantation, and embryos that do not develop are discarded.