It is an additional technique to In Vitro Fertilization and consists of allowing the embryos to reach the fifth or sixth day of development (BLASTOCYST) in the laboratory in order to have a better morphological selection of embryos.

It is indicated in patients who have undergone previous In Vitro Fertilization treatments and pregnancy has not been achieved in women over 38 years old, patients undergoing Preimplantation Genetic Diagnosis.