Advances in reproductive technology have made it possible to learn more about embryos before pregnancy begins.

Two important types of genetic testing used during IVF are PGT-A and PGT-M. These two tests serve different purposes and can play a crucial role in helping intended parents make informed decisions.

What Are PGT-A and PGT-M? 

PGT-A (Preimplantation Genetic Testing for Aneuploidy) is used to screen embryos for chromosomal abnormalities, specifically, whether an embryo has the correct number of chromosomes.

PGT-M (Preimplantation Genetic Testing for Monogenic Disorders) is used to detect specific inherited genetic conditions caused by mutations in a single gene.

Both tests are performed on a small biopsy taken from the embryo during IVF.

PGT-A Testing in IVF

PGT-A helps classify embryos into three main categories:

• Euploid: The embryo has the correct number of chromosomes. These embryos have the highest likelihood of resulting in a successful pregnancy and a healthy baby.
• Aneuploid: The embryo has missing or extra chromosomes. These embryos are not recommended for transfer due to a very low chance of success and higher risk of complications.
• Mosaic: The embryo contains a mix of normal (euploid) and abnormal (aneuploid) cells. Mosaic results can vary:
• Low-level mosaic embryos may sometimes be considered for transfer
• High-level mosaic embryos are generally less likely to be recommended

It’s important to understand that mosaicism is complex. Because only a small sample of cells is tested, it’s not always possible to determine the exact proportion of abnormal cells in the entire embryo. For this reason, decisions about mosaic embryos are made carefully.

PGT-A helps identify which embryos are most likely to lead to a healthy pregnancy. By prioritizing euploid embryos, clinicians can improve implantation success rates, reduce the risk of miscarriage, and increase the chances of healthy birth.

PGT-M Genetic Testing

PGT-M is recommended for individuals or couples who are at risk of passing down a specific genetic condition. This includes inherited disorders caused by mutation in a single gene.

You may benefit from PGT-M if:

• You and your partner are carriers of the same autosomal recessive condition
• You are a carrier of an X-linked condition
• You or your partner has an autosomal dominant condition
• You or your partner carries a mutation like a hereditary cancer syndrome
• You have had previous pregnancy or child affected by a genetic disorder
• You are interested in HLA matching for medical purposes

How Embryo Genetic Testing Works?

During the testing process, a few cells are carefully removed from the outer layer of the embryo, known as the trophectoderm. These cells will eventually form the placenta. Importantly, the inner cell mass, the part that develops into the fetus, is not disturbed. This approach allows for genetic analysis while preserving the embryo’s developmental potential.

Why Genetic Screening Matters Before IVF?

Before starting IVF, egg freezing, or embryo creation, it is strongly recommended to undergo genetic carrier screening. This testing helps determine whether you or your partner carry genes that could lead to inherited conditions.

If a risk is identified, PGT-M can then be used to test embryos and ensure that only those without the condition are selected for transfer.

Final Thoughts: Making Informed Decisions 

Both PGT-A and PGT-M provide valuable insights that can guide embryo selection and reduce the risk of genetic conditions. While no test can guarantee a perfect outcome, these tools significantly improve the ability to make informed decisions.

If you’re considering IVF, speak with your fertility specialist at Beverly Hills Fertility to help you understand which testing options are right for you and your family-building goals.