During IVF, embryos may undergo PGT-A (Preimplantation Genetic Testing for Aneuploidy) to evaluate the number of chromosomes present in sampled embryo cells.

Euploid embryo:
A euploid embryo has the expected number of chromosomes — normally 46. These embryos generally have the highest chance of implantation and the lowest risk of miscarriage related to chromosome abnormalities.

Aneuploid embryo:
An aneuploid embryo has an abnormal number of chromosomes, meaning one or more chromosomes may be missing or duplicated. Examples include trisomy 21 (Down syndrome), trisomy 18, and trisomy 13. Many aneuploid embryos do not implant or may result in miscarriage.

Mosaic embryo:
A mosaic result means the tested sample contains a mixture of cells with normal and abnormal chromosome findings. Some mosaic embryos may still develop into healthy pregnancies, depending on the chromosomes involved and the degree of mosaicism.

PGT-A is a screening test, not a diagnostic test. Embryo results and transfer decisions should always be reviewed with your fertility specialist and genetic counsellor.