1. Home
2. Resources
3. Blog
4. What is Preimplantation Genetic Testing (PGT)?

What is Preimplantation Genetic Testing (PGT)?

What is Preimplantation Genetic Testing (PGT)?

Preimplantation Genetic Testing (PGT) is a procedure used to test embryos for genetic abnormalities before they are implanted into the uterus as part of the in-vitro fertilization (IVF) process. The primary goal of PGT is to identify embryos that are free of specific genetic conditions and/or chromosomal abnormalities, thereby increasing the chances of a successful pregnancy and reducing the risk of genetic disorders in the offspring. PGT takes place before the embryo is transferred into the uterus, unlike first-trimester prenatal screening, which is usually conducted 10-13 weeks into pregnancy.

Types of PGT

1. PGT-A (Preimplantation Genetic Testing for Aneuploidy): PGT-A is the most common type of preimplantation genetic testing. This tests for chromosomal abnormalities and involves counting the number of chromosomes in a sampling of cells from each embryo produced during your IVF cycle. Embryos with missing or extra chromosomes, known as aneuploid, can lead to conditions like Down syndrome, Turner syndrome, and others. Aneuploid embryos have a higher risk of implantation failure and miscarriage. PGT-A is recommended for all women due to the increased chance of a successful pregnancy.
2. PGT-M (Preimplantation Genetic Testing for Monogenic/Single Gene Disorders): PGT-M tests for specific genetic disorders caused by mutations in a single gene, or monogenic conditions. Patients with a family history or inherited genetic conditions such as cystic fibrosis, Huntington's disease, and sickle cell anemia may be good candidates for PGT-M.
3. PGT-SR (Preimplantation Genetic Testing for Structural Rearrangements): PGT-SR screens embryos for missing and extra chromosomal material, similar to PGT-A, but at a more detailed level. This tests for chromosomal structural rearrangements, such as translocations or inversions, which can affect the viability of the embryo or lead to genetic disorders. This form of PGT may be customized to your personal profile and needs and is only recommended if you are known to have a structural rearrangement of your own chromosomes.

When is PGT a good option?

Preimplantation Genetic Testing (PGT) can be beneficial for several groups of people:

1. Couples with a History of Genetic Disorders: Couples who are carriers of genetic disorders or have a family history of genetic diseases may use PGT to ensure their children do not inherit these conditions.
2. All Women Undergoing IVF: PGT-A enables your physician to identify genetically healthy embryos to transfer, increasing the chances of successful implantation and pregnancy.
3. Couples with Recurrent Pregnancy Loss: Couples who have experienced multiple miscarriages may use PGT to identify embryos with chromosomal abnormalities that could lead to pregnancy loss.
4. Carriers of Chromosomal Rearrangements: Individuals with balanced translocations or other structural chromosomal abnormalities might use PGT to select embryos without unbalanced rearrangements that could lead to miscarriage or genetic disorders.
5. Single Gene Disorder Carriers: Couples where one or both partners are carriers of a specific single-gene disorder (e.g., Tay-Sachs disease, thalassemia) might use PGT-M to select embryos without the disorder.
6. Same-Sex Couples and Single Parents Using Donor Gametes: Individuals or couples using donor eggs or sperm might use PGT to screen for genetic abnormalities, ensuring the healthiest possible embryos.

Benefits of PGT:

• Reduces the risk of miscarriage or genetic disorders in offspring.
• Increases the likelihood of a successful pregnancy and live birth from a single embryo transfer.
• Improves the efficiency of your IVF cycles – fewer embryo transfers needed (on average) to achieve pregnancy.
• Provides peace of mind for parents with known genetic risks.

Considerations

• PGT involves additional costs and may not be covered by insurance.
• The procedure requires IVF.
• Not all genetic conditions can be detected with PGT.

Conclusion

Preimplantation genetic testing (PGT) offers a powerful option for couples facing specific genetic risks, helping them to make informed decisions about their reproductive choices. Our fertility specialists can help decide if genetic testing is necessary and what tests are right for you.

Schedule a consultation to learn more about preimplantation genetic testing and how it could benefit you.

See all articles