The Biggest Misconceptions about PGT-A

Preimplantation genetic testing for aneuploidy (PGT-A) has become a common part of IVF, providing information about the number of chromosomes in cells taken from an embryo. While the technology is very advanced, understanding what PGT-A can and cannot tell us is essential when making decisions about embryo transfer. 

During PGT-A, a small number of cells are removed from an embryo and analyzed for a chromosome copy number. Results may indicate that the cells tested are euploid (the expected number of chromosomes), aneuploid (an abnormal number), or mosaic (a mixture of cells with different chromosome numbers). Testing can also identify certain segmental chromosome abnormalities. 

However, an embryo can contain hundreds of cells, while only a few are analyzed. This means the biopsy does not necessarily represent every cell within the embryo. 

Another important consideration is which cells are tested. PGT-A samples cells from the trophectoderm, the outer layer of the embryo that primarily contributes to the placenta. The cells that ultimately develop into the fetus are not directly biopsied. 

Because embryos can contain cells with different chromosome profiles, a PGT-A result may not always provide a complete picture of the embryo's developmental potential. This is particularly important when interpreting mosaic or abnormal results. 

An abnormal PGT-A result also does not necessarily mean that an embryo cannot become a healthy baby. An abnormal result means that the cells examined during the biopsy showed an abnormal chromosome pattern. It does not automatically mean that every cell in the embryo is abnormal or that the embryo cannot result in a healthy pregnancy. 

The significance of a PGT-A result depends on the specific chromosome involved, the type of abnormality, and other clinical factors. Some embryos with abnormal or mosaic results can still result in pregnancies and healthy births, making PGT-A one piece of information rather than an absolute prediction of an embryo’s potential. Its value may also vary by patient based on different factors.  

Factors such as age, number of embryos, ovarian response, reproductive history, and individual treatment goals should all be considered when discussing whether PGT-A is appropriate. 

PGT-A is an important advancement in reproductive medicine, but it is not a guarantee of implantation or a healthy pregnancy. A normal result does not guarantee that an embryo will result in a baby, and an abnormal result does not always mean that an embryo has no reproductive potential. 

At the Center for Human Reproduction, we believe patients should have access to clear, evidence-based information, so they can have informed conversations with their fertility specialists about embryo testing and their individual treatment options. If you’re interested in learning more, visit the link here to watch Dr. David Barad on The Egg Factor.