PGT-A (preimplantation genetic testing for aneuploidy) is a screening method used during IVF to check embryos for an abnormal number of chromosomes. Many patients in Thailand consider PGT-A to increase the chance of a successful pregnancy, especially after repeated implantation failure or at an older maternal age. However, PGT-A is not a guarantee of a healthy baby, and its accuracy depends on several factors. This guide explains what PGT-A can and cannot tell you, how results are interpreted, and what to consider when choosing PGT-A in Thailand.
What Is PGT-A and How Does It Work?
PGT-A is a test performed on embryos created through IVF. A few cells are removed from the embryo (usually from the trophectoderm, which becomes the placenta) and analyzed for chromosomal abnormalities. The goal is to identify embryos with the correct number of chromosomes (euploid) versus those with missing or extra chromosomes (aneuploid). Transferring a euploid embryo may reduce the risk of miscarriage and increase the chance of implantation, but it does not guarantee pregnancy or a healthy child.
How Accurate Is PGT-A?
PGT-A is highly accurate in detecting chromosomal abnormalities in the sampled cells, but it is not 100% perfect. The accuracy can be affected by:
- Mosaicism: Embryos may have a mix of normal and abnormal cells. A biopsy may not capture the true chromosomal status of the entire embryo.
- Technical limitations: The testing method (e.g., next-generation sequencing) has a small error rate.
- Embryo self-correction: Some embryos with abnormal cells may self-correct during development, leading to a false positive result (embryo labeled abnormal but could have developed normally).
In Thailand, as elsewhere, the accuracy of PGT-A depends on the laboratory’s quality, the biopsy technique, and the genetic testing platform used. However, no specific accuracy rates can be provided without official data from Thai clinics.
What Do PGT-A Results Mean?
PGT-A results are typically reported as:
- Euploid: Normal chromosome number – suitable for transfer.
- Aneuploid: Abnormal chromosome number – generally not recommended for transfer.
- Mosaic: Mixed cell population – may be considered for transfer in some cases, but with caution.
- No result: The test failed to produce a result – may require re-biopsy or additional testing.
It is important to understand that PGT-A does not test for all genetic disorders. It only screens for chromosomal abnormalities, not single-gene disorders (which require PGT-M) or structural rearrangements (which require PGT-SR).
Factors That Can Affect PGT-A Accuracy in Thai Labs
Several factors can influence the reliability of PGT-A results in Thailand:
- Embryo biopsy timing: Biopsy is usually done on day 5 or 6 (blastocyst stage). Biopsy too early or too late may affect accuracy.
- Number of cells biopsied: A sufficient number of cells is needed for reliable analysis.
- Laboratory quality: The experience of the embryology team and the laboratory’s accreditation play a role.
- Genetic testing platform: Different platforms have varying levels of sensitivity and specificity.
- Embryo quality: Poor-quality embryos may have higher rates of mosaicism, affecting interpretation.
When considering PGT-A in Thailand, ask the clinic about their laboratory protocols, quality control measures, and how they handle inconclusive or mosaic results.
PGT-A vs. Other Genetic Tests
PGT-A is often confused with other types of preimplantation genetic testing:
- PGT-M (monogenic disorders): Tests for specific single-gene diseases, such as cystic fibrosis or thalassemia.
- PGT-SR (structural rearrangements): Tests for chromosomal structural abnormalities, such as translocations.
These tests are different from PGT-A and are used for different medical indications. Some patients may need more than one type of testing.
Who Might Consider PGT-A?
PGT-A is not recommended for everyone. It may be considered in cases such as:
- Advanced maternal age (usually over 35)
- Previous miscarriage or implantation failure
- Severe male factor infertility
- Previous aneuploidy pregnancy
However, the decision to use PGT-A should be made in consultation with a fertility specialist, considering individual circumstances and risks.
Limitations and Risks of PGT-A
PGT-A has limitations that patients should understand:
- Not a guarantee: A euploid embryo may still fail to implant or result in miscarriage.
- Biopsy risk: The biopsy procedure carries a small risk of damaging the embryo.
- False positives/negatives: As mentioned, mosaicism and technical errors can lead to incorrect results.
- Cost: PGT-A adds to the cost of IVF, and not all patients will benefit.
It is essential to have realistic expectations and discuss the potential benefits and risks with your doctor.
Questions to Ask Your Clinic in Thailand
Before undergoing PGT-A in Thailand, consider asking:
- What genetic testing platform do you use, and what is its accuracy rate?
- How many cells are biopsied, and what is your success rate for obtaining a result?
- How do you handle mosaic embryos?
- What is your laboratory’s accreditation and quality control process?
- How will PGT-A results be interpreted in my specific case?
Next Steps
If you are considering PGT-A in Thailand, take these steps:
- Consult with a fertility specialist to determine if PGT-A is appropriate for you.
- Research clinics and their laboratory standards.
- Ask detailed questions about the testing process and result interpretation.
- Consider the financial implications and whether PGT-A is covered by any packages.
For more information on PGT in Thailand, see our PGT in Thailand guide. You may also find our general guides and FAQ helpful.
Frequently asked questions
Is PGT-A 100% accurate?
No, PGT-A is not 100% accurate. It can have false positives and false negatives due to mosaicism, technical limitations, and embryo self-correction. However, it is a reliable screening tool when performed in a quality laboratory.
What is a false positive in PGT-A?
A false positive occurs when PGT-A labels an embryo as abnormal (aneuploid) when it actually has the potential to develop into a healthy baby. This can happen due to mosaicism or technical errors.
How accurate is PGT-A in Thailand?
The accuracy of PGT-A in Thailand depends on the clinic's laboratory standards, biopsy technique, and testing platform. There is no single accuracy rate for the entire country. It is best to ask your specific clinic about their quality control and success rates.
Can PGT-A results be wrong?
Yes, PGT-A results can be wrong, though rarely. Mosaicism and technical errors can lead to incorrect results. This is why it is important to discuss the limitations with your doctor.
Does PGT-A guarantee a healthy baby?
No, PGT-A does not guarantee a healthy baby. It only screens for chromosomal abnormalities and does not detect all genetic disorders or birth defects. A euploid embryo may still fail to implant or miscarry.
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Medical information notice: This article is educational and does not replace individual assessment, diagnosis, genetic counselling or treatment advice from a licensed clinician. Provider services, availability, fees and policies should be verified directly before booking.