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Greetings from Amma Bear,
The path to understanding fertility treatments can feel like navigating a labyrinth. Terms like PGD, PGT, and PGS are commonly seen when researching genetic screenings linked to IVF. Allow me to guide you through this maze of abbreviations.
PGD (Preimplantation Genetic Diagnosis):
What it is: PGD is a specialized procedure used to biopsy and analyze cells from embryos for specific genetic or chromosomal disorders.
When it’s recommended: Doctors typically recommend PGD in cases where:
How it’s performed: During the IVF process, a few cells are removed from the embryo around its fifth day of development (blastocyst stage). These cells are then analyzed for specific genetic mutations.
Timeframe: The biopsy itself is swift, but the genetic analysis can take about one to two weeks.
Accuracy: PGD is generally accurate, but like all tests, there is a small chance of misdiagnosis. Studies indicate that PGD can significantly reduce the risk of passing on a genetic disorder.
PGS (Preimplantation Genetic Screening):
What it is: Often referred to as PGT-A, this method screens embryos for the correct number of chromosomes.
When it’s recommended: PGS is commonly advised for:
How it’s performed: Similar to PGD, cells are biopsied from the embryo at the blastocyst stage and then screened for aneuploidies (incorrect number of chromosomes).
Timeframe: Analysis usually takes about one week. However, this can vary depending on the clinic and the specifics of the test.
Accuracy: PGS has shown a high degree of accuracy in detecting chromosomal abnormalities2, though it's crucial to discuss the potential for false positives or negatives with your doctor.
PGT (Preimplantation Genetic Testing):
What it is: An encompassing term, PGT includes both PGD and PGT-A (previously known as PGS). Advances have given rise to subsets like PGT-M (for specific single-gene disorders) and PGT-SR (for structural chromosomal rearrangements).
When it’s recommended: The recommendation for PGT depends on its specific subtype (PGT-A, PGT-M, PGT-SR). As an overarching method, it's advised when there's a need to identify genetic defects in embryos created through IVF before pregnancy.
How it’s performed: The method is similar to PGD and PGS, involving biopsy at the blastocyst stage followed by the requisite genetic testing.
Timeframe: Depending on the exact test, results can be obtained typically within one to two weeks.
Accuracy: As with PGD and PGS, PGT's accuracy is high, but results can vary depending on the specific test and individual factors3.
These testing methods offer invaluable insights, especially when there's a concern about potential genetic or chromosomal abnormalities. However, they also add to the duration and complexity of the IVF process.
As well, while genetic testing offers a clearer picture of potential genetic or chromosomal concerns, it's essential to weigh the benefits against potential challenges. Always consult with your healthcare provider, who can offer tailored guidance and answer any concerns you might have.
With admiration for the steps you're making,
Amma Bear
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