Blastocyst culture is a procedure in which embryos are cultured for 5 days to the blastocyst stage. Resetting the embryos later on day 5 allows the development of the embryos to be observed for longer. The longer time between egg collection and embryo transfer also gives the body more time to recover from the hormone treatment. This means that a blastocyst often has a higher chance of implanting and thus leading to pregnancy. A blastocyst culture is most often performed when there are many fertilized eggs available. The costs for balstocyst culture are not covered by all health insurance companies.

Unfortunately, only about a third of all fertilized eggs develop into a blastocyst. As part of the so-called German Middle Way, several eggs can also be cultured. The day after the puncture, various factors are used to determine how many eggs are needed to obtain the desired number of embryos on the day of the transfer. If there are more embryos than are transferred, it makes sense to freeze them.

The costs for blastocyst culture are not covered by all health insurance companies.