In order to implant the embryo, it must form a blastocyst, expand and leave the zona pellucida (the outer layer that surrounds it), so implantation does not begin until 6-7 days after fertilization. If the transfer is made on day 3, it would take 2-3 more days for the time to begin implantation to arrive, and if it is made on day 5, 1 or 2 more days.
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Sara Salgado
Embryologist
Degree in Biochemistry and Molecular Biology from the University of the Basque Country (UPV/EHU). Master's Degree in Human Assisted Reproduction from the Complutense University of Madrid (UCM). Certificate of University Expert in Genetic Diagnosis Techniques from the University of Valencia (UV).
