Embryonic mosaicism: What does it mean clinically?

Embryonic mosaicism continues to represent a complex phenomenon that is considered by many authors as a limiting factor in the interpretation of PGT-A cycles results. A mosaic embryo is characterized by the presence of cell populations with at least two different karyotypes. There are controversial aspects related to embryonic mosaicism, such as the great variability in the incidence reported between laboratories and clinics, which in turn is related to the existence of false positives during the diagnosis. These false positives can also affect the results after the transfer of these embryos. Numerous publications have analyzed the results of transferring this type of embryo. The majority agrees that although worse clinical results are achieved that, when transferring a euploid embryo, it is possible to achieve an evolutionary pregnancy with a healthy birth. The objective of this article is to provide tools that allow the professional to advise those patients who perform a PGT-A cycle about this conflictive aspect of it.