Pre-Implantation Genetic Testing (PGT)
Pre-Implantation Genetic Testing (PGT) is a revolutionary technology that has transformed the field of reproductive medicine. A group of genetic tests evaluate embryos before transfer to the uterus. This technology is used with in vitro fertilization (IVF) to increase the potential for a successful pregnancy and delivery.
What is PGT?
To analyze the embryos before transfer genetically. The primary goal of PGT is to identify genetic defects within embryos before they are transferred into the uterus, preventing certain genetic diseases or disorders from being passed on to the child.
Types of PGT
There are three specific types of PGT: PGT-M (monogenic), PGT-A (aneuploidy), and PGT-SR (structural rearrangements)
- PGT-M is targeted to single gene disorders. It is used when a specific genetic disease needs to be identified in the embryo. This may be desired to avoid passing on a genetic disease or to choose a particular genetic tendency. (Source: New Hope Fertility) PGT-M testing offers many benefits for patients who carry sex-linked genetic disorders, single gene and chromosomal disorders, and patients over the age of 35.
- PGT-A involves checking embryos for abnormalities in the number of chromosomes. Embryos with missing or extra chromosomes, known as aneuploid embryos, have less chance of developing into a baby. Or, less commonly, it may result in a baby being born with a genetic condition. PGT-A gives information about embryo genetic health to help your care team select the best embryo for transfer and improve your chances of achieving a successful pregnancy. PGT-A can also be used by couples who wish to choose the sex of their intended child, also known as gender selection (Source: CNY Fertility)
- PGT-SR is a genetic test designed to detect inherited chromosomal rearrangements and increase the chance of a successful pregnancy. This testing is commonly considered after recurrent miscarriages or the birth of an offspring with chromosomal abnormalities, as affected couples are generally healthy and unaware of the chromosomal structural rearrangement that they carry.
Benefits of PGT
The benefits of PGT are numerous. For one, it allows for selecting the healthiest embryos for implantation, thereby increasing the chances of a successful pregnancy. It also reduces the risk of having a child with a genetic disorder. For couples who have a history of genetic disorders or who are carriers of a specific genetic mutation, PGT can provide reassurance and reduce anxiety associated with passing on the condition to their child.
Furthermore, PGT can help to reduce the risk of miscarriage, which is often associated with chromosomal abnormalities. (Source: Illume Fertility) By screening out embryos, the likelihood of a successful pregnancy is increased.
Limitations of PGT
Despite its benefits, PGT has limitations. False-positive and false-negative results are possible. Patients and healthcare providers should be aware that a “normal” or negative PGT result is not a guarantee of a newborn without genetic abnormalities. PGT is a powerful tool in the field of reproductive medicine, offering hope to couples struggling with infertility or genetic disorders. However, like all medical procedures, it is not without its limitations and should be considered as part of a comprehensive approach to fertility treatment.
Sources:
New Hope Fertility - PGT-A vs. PGT-M: What is the Difference? - New Hope Fertility Center
CNY Fertility - PGT-A: Preimplantation Genetic Testing for Aneuploidy | CNY Fertility
Illume Fertility - Your Guide to Preimplantation Genetic Testing (PGT): Cost, FAQs & More (illumefertility.com)