Blastocyst culture

Regardless of whether after IVF or IVF/ICSI, as well as in what is known as the “cryo cycle”, embryos can be cultivated for 2 to 3 days, or up to day 5. This is possible even in Germany, with its strict Embryonic Protection Act. It is performed with great success by a few centres. However, the problem in Germany is that the cells to be transferred have to be chosen on day 1 of the culture, i.e. generally 2 – 3 embryos per cycle (see the IVF Register But not even every “top-quality embryo” reaches this stage as the conditions in an incubator are not as ideal as those in the uterus. It must be assumed that only 25 – 50 % of the “day 2 embryos” will become blastocysts.

The main advantage of the 5 day culture can only be used to the patient’s benefit if the selection can be made from all (i.e. more than 2 – 3) of the embryos. Therefore, with few exceptions, it makes little sense in Germany to perform the blastocyst culture, given that a potential pregnancy could even not occur at all as a result.

Given the requirements of the German Embryonic Protection Act, it is better for the pregnancy rate to perform the embryo transfer on day 2 or 3.

Blastocyst development
Series of images of an embryo, which hatches in figure 5