The current trend in assisted reproduction techniques is to transfer a single embryo at the blastocyst stage in order to avoid multiple pregnancies. In this way, it is possible to achieve pregnancy without compromising the gestation rate.
Blastocyst transfer is the appropriate technique for patients with a large number of fertilised embryos. With sequential culture, a natural selection of the embryo with the highest implantation potential is achieved.
However, it is important to evaluate in each case whether it is better to transfer embryos on day 3 or day 5 of development. To do this, factors such as the number of embryos, embryo quality, whether IVF cycles have been performed previously, whether complementary techniques such as PGD are to be performed, etc. must be taken into account.