Does the timing of the transfer change if PGD is done or if donated embryos are used?

It will depend on when the PGD biopsy is done or when the donated embryos are in development. If the PGD biopsy is done on the 3rd day, the embryos can be transferred fresh on the 5th day or frozen for a subsequent transfer, either on the 3rd day, immediately after thawing, or on the 5th day, leaving them in culture for two days after thawing. However, if the biopsy is done on day 5, the embryos must necessarily be frozen.

In the case of donated embryos, it will also depend on the protocol to be followed by the centre. The transfer can be made as soon as they are thawed or you can wait to see how they develop.