Preimplantation Genetic Testing for Aneuploidy (PGT-A) is a genetic screening tool used with In Vitro Fertilization (IVF). It identifies chromosomal abnormalities within embryos before uterine transfer. This article explores PGT-A’s potential benefits and important considerations to help individuals make an informed choice.
Understanding PGT-A
PGT-A involves checking embryos for an abnormal number of chromosomes, a condition known as aneuploidy. Aneuploidy means a cell has extra or missing chromosomes, differing from the typical 46 chromosomes. This chromosomal imbalance is a frequent cause of IVF failure, miscarriage, and can lead to genetic conditions like Down syndrome.
The process typically begins five to six days after an egg is fertilized, when the embryo reaches the blastocyst stage. A small biopsy is performed, removing cells from the trophectoderm, the outer layer destined to become the placenta. These biopsied cells are sent for analysis, while embryos are frozen.
PGT-A specifically screens for chromosome number, but it does not screen for single gene disorders or all genetic conditions. The test aims to identify euploid embryos (correct chromosome number) from aneuploid embryos.
Potential Advantages
One of the primary goals of PGT-A is to improve the chances of a successful pregnancy and increase implantation rates. By identifying and selecting embryos with the correct number of chromosomes, the likelihood of an embryo successfully implanting in the uterus is enhanced. This helps fertility specialists choose the embryo most likely to lead to a healthy pregnancy.
PGT-A can also significantly reduce the risk of miscarriage, particularly for certain patient groups. Chromosomal abnormalities are a common reason for early pregnancy loss, accounting for about half of all miscarriages. Selecting euploid embryos for transfer can therefore decrease the incidence of miscarriage.
Using PGT-A may decrease the number of IVF cycles required to achieve a successful pregnancy, potentially shortening the overall time to conception. PGT-A also facilitates single embryo transfer (SET), which reduces the risks associated with multiple pregnancies, such as premature birth and low birth weight.
Important Considerations
Despite its potential benefits, PGT-A involves several important considerations. One complexity arises from mosaicism, a condition where an embryo contains a mixture of chromosomally normal and abnormal cells. The presence of mosaicism introduces uncertainty, as the biopsy sample may not fully represent the entire embryo. While some mosaic embryos can result in healthy live births, the outcomes can be less predictable.
The financial aspect is another significant consideration, as PGT-A adds a substantial cost to an IVF cycle. The price for PGT-A testing can range from approximately $4,000 to $10,000 per cycle in the United States, and this cost often excludes biopsy fees. Many insurance plans do not cover PGT-A, making it an out-of-pocket expense for many patients.
The embryo biopsy procedure itself carries a minimal risk of damage, though advancements have made it generally safe. Embryos must also undergo freezing and thawing. There is also a small possibility of false positive or false negative results from PGT-A testing. In some cases, PGT-A may reveal that all tested embryos are aneuploid, resulting in no embryos suitable for transfer. This outcome can be emotionally challenging for patients.
Who Should Consider PGT-A?
PGT-A is frequently recommended for specific patient profiles where the likelihood of aneuploidy is higher or where previous reproductive challenges suggest its potential benefit. One common indication is advanced maternal age, typically for women over 35, as the risk of chromosomal abnormalities in eggs and embryos increases significantly with age. PGT-A can help mitigate this age-related decline by identifying chromosomally healthy embryos.
Individuals who have experienced recurrent pregnancy loss or multiple miscarriages are often candidates for PGT-A. Since chromosomal abnormalities are a leading cause of miscarriage, screening embryos can help reduce the risk of future losses. Similarly, patients who have undergone multiple previous failed IVF cycles, particularly when good quality embryos were transferred, may benefit from PGT-A to identify underlying chromosomal issues.
Couples facing severe male factor infertility might also consider PGT-A, as sperm quality can sometimes influence embryo genetics. While research is ongoing, PGT-A can potentially help select the most viable embryos in these cases. Lastly, PGT-A is a consideration for couples with a known chromosomal rearrangement in one or both partners, as it can identify embryos that have inherited an unbalanced form of the rearrangement.
Making an Informed Decision
The decision to proceed with PGT-A is a deeply personal one, influenced by individual circumstances, medical history, and financial considerations. Each patient’s unique situation must be carefully evaluated to determine if the potential advantages outweigh the complexities and costs.
It is important to have a thorough discussion with a fertility specialist, such as a reproductive endocrinologist. This medical professional can review your specific case, explain the potential benefits and drawbacks of PGT-A in your context, and help you weigh the scientific evidence alongside your personal values and preferences. Collaborating with your care team ensures that you make a decision that aligns with your reproductive goals and overall well-being.