Embryo biopsy is a technique that enables cells to be obtained from an embryo during their in vitro development to undergo a genetic analysis. This can be done on day 3 of embryonic development by extracting one or two cells without negatively affecting embryonic implantation capacity or development.
This technique may also be done on days 5 and 6 of development when the embryo is at the blastocyst stage. At this stage, a biopsy may be done with 4-5 cells from the part of the embryo known as the trophoectoderm. For embryo biopsies done on days 5 or 6 of development, it may be necessary to freeze embryos until the diagnosis has been completed and to perform the transfer in a subsequent cycle.