Embryo Genetic Evaluation (PGT-A/SR/M)
What is Embryo Genetic Evaluation?
Embryo Genetic Evaluation, commonly referred to using the term Preimplantation Genetic Testing of embryos, involves analyzing embryos for specific genetic or chromosomal abnormalities before transferring them to the uterus. The different variations include:
- PGT-A (Preimplantation Genetic Testing for Aneuploidies): Evaluates embryos for the correct count of chromosomes (46)
- PGT-SR (Preimplantation Genetic Testing for Structural Rearrangements): Tests for chromosomal rearrangements that can lead to pregnancy loss or birth defects
- PGT-M (Preimplantation Genetic Testing for Monogenic/Single Gene Disorders): Detects single-gene disorders ensuring they are not passed on to offspring / next generation
Who can opt for Embryo Genetic Evaluation?
- Couples with affected first child
- Couples with known genetic disorders
- Women of advanced maternal age
- Individuals with a history of recurrent miscarriages
- Couples with repeated IVF failures
- Those with a family history of chromosomal disorders
- Abnormal prenatal karyotype
What are the pre-requisites for Embryo Genetic Evaluation?
- Successful IVF or ICSI procedure resulting in viable embryos
- Informed consent about the testing process, potential results, and implications
- A comprehensive genetic counseling session
How does Embryo Genetic Evaluation work?
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Post-fertilization & once the embryos reach a blastocyst stage, a few cells are biopsied from the outer layer (trophectoderm) without harming the embryo
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The biopsied embryos are then kept frozen in liquid nitrogen cryo tanks for future use
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The extracted cells are then genetically analyzed for chromosomal or genetic abnormalities
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Only embryos that are deemed to have a correct count of chromosomes (euploid) are considered for transfer to the uterus
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Embryos that are not affected by target mutation are considered for transfer to the uterus
Post-Embryo Genetic Evaluation procedure
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Healthy embryos are either transferred in a subsequent cycle or frozen for future use
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Genetic counselling may be recommended to interpret and understand the results, especially if abnormalities are detected
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Embryos with detected abnormalities can either be discarded or donated for research, based on the patient’s preference
Frequently Asked Questions
Does the biopsy harm the embryo?
Modern techniques are designed to be very safe, and when performed by experienced professionals, the risk to the embryo is minimal.
Is PGT 100% accurate?
While PGT greatly reduces the risk of genetic or chromosomal abnormalities, no test is 100% accurate. There’s a small chance of false positives or negatives.
Can PGT ensure a successful pregnancy?
PGT improves the chances of a successful pregnancy by transferring genetically healthy embryos thus reducing the risk of miscarriage. However, other factors also influence the outcome of an IVF cycle.