Traditionally, embryos were transferred to the uterus after only a few days of growth. However, with blastocyst culture and transfer, the embryos are allowed to continue developing in the laboratory for an additional 2-3 days. This allows the embryologist to select the healthiest and most viable embryos for transfer, which can increase the chances of a successful pregnancy.

Blastocyst culture and transfer is also beneficial because it allows for better synchronization between the embryo and the uterus. The uterus is more receptive to an embryo at the blastocyst stage, which can increase the chances of implantation and a successful pregnancy.

The process of blastocyst culture and transfer involves removing the embryos from the incubator and examining them under a microscope to ensure they have reached the blastocyst stage. The embryologist then selects the healthiest embryos for transfer and implants them into the uterus of the female partner  Any remaining embryos can be frozen for future use.