What is PGT?
Genetic testing isn’t unique to IVF participants. Even women that conceive naturally often undergo genetic screening to determine if there are any chromosomal abnormalities. However, preimplantation genetic testing (PGT) is slightly different since the screening occurs before the embryos are transferred to a woman’s uterus for implantation. PGT can include preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS) tests.
Comparing PGD and PGS
While both genetic tests are administered before embryos are transferred to the uterus, PGD and PGS screen for different outcomes. PGD is best suited for known carriers of specific genetic disorders. During the test, technicians will screen for the particular hereditary condition the woman or couple outlines. PGS is more closely related to the prenatal genetic testing pregnant women undergo in the first trimester. Instead of screening for a specific disorder, technicians are looking for chromosomal abnormalities. If a chromosomal problem is identified, the couple can choose not to transfer the affected embryo to the uterus, decreasing the risk of miscarriage.
How is PGT performed?
Preimplantation genetic testing is often combined with assisted hatching. Right before the fertilization process, a lab technician will crack the egg’s exterior, allowing sperm to penetrate the egg easier. Once fertilization occurs and the embryo transforms into a blastocyst, cells are biopsied from the exterior for genetic analysis. After testing, embryos deemed healthy will then be transferred to a woman’s uterus in hopes of implantation. In most cases, the additional testing adds 7-10 days to the IVF timeline.
A woman or couple must first be undergoing IVF to be considered for any form of PGT. Fertility patients over 37 or with a history of multiple miscarriages are also good candidates. Couples with a family history of known inherited genetic diseases are also encouraged to undergo PGD to obtain important information about the risks of inherited conditions.
Maximizing pregnancy potential
Although IVF is the most popular and successful form of assisted reproductive therapy (ART), there is no guarantee of live birth. However, undergoing PGD or PGS can help to minimize the risk of poor pregnancy outcomes and provide added peace of mind for hopeful potential parents. Test early for the best shot at a successful pregnancy.