PGT-A Testing in Thailand for International Patients: Who It May Help and What It Screens

PGT-A (preimplantation genetic testing for aneuploidy) is a laboratory test that can be performed on embryos created during IVF. It looks for extra or missing chromosomes — a condition called aneuploidy — before an embryo is transferred. It is not a treatment, not a guarantee of pregnancy, and not automatically necessary for everyone. Whether it is useful depends on your age, your IVF history, how many embryos you have, and what you and your clinician are trying to learn. This guide explains what PGT-A screens, how it differs from other PGT tests, who may reasonably consider it, and what to confirm directly with a clinic in Thailand.

At a glance

• What it is: A lab test on a small sample of embryo cells, usually at the blastocyst stage.
• What it screens: Extra or missing whole chromosomes (aneuploidy), not single-gene disorders and not all structural chromosome problems.
• What it does not do: It cannot guarantee a healthy pregnancy, a live birth, or a healthy child. It does not diagnose a disease in you.
• Who may consider it: Often discussed with older patients, those with repeated implantation failure or recurrent pregnancy loss, or those with many embryos who want more information before transfer.
• Key trade-off: More information about chromosome number, but also possible embryo loss from testing, biopsy risk, cost, and the chance of a result that is hard to interpret.
• In Thailand: Availability, lab arrangements, and which patients are offered PGT-A vary by clinic. Confirm details directly.

What PGT-A actually screens

Human cells normally contain 46 chromosomes arranged in 23 pairs. Aneuploidy means there is an extra or missing chromosome. Common examples include trisomy 21 (an extra copy of chromosome 21), trisomy 18, and trisomy 13, as well as missing or extra sex chromosomes. Aneuploidy is a common cause of miscarriage and can also be present in embryos that fail to implant.

PGT-A estimates the number of chromosomes in the cells sampled from an embryo. It does not read the full DNA sequence, so it does not detect most single-gene conditions such as cystic fibrosis or spinal muscular atrophy. It also has limits for certain structural rearrangements, small deletions or duplications, and mosaic results (where different cells in the same embryo have different chromosome numbers).

Because only a few cells are removed, PGT-A is a screening test, not a definitive diagnosis. A “normal” result reduces but does not eliminate the chance of aneuploidy, and it cannot predict whether an embryo will implant, grow normally, or result in a healthy baby.

PGT-A, PGT-M, and PGT-SR: how they differ

PGT is an umbrella term. The three main types answer different questions:

Test	What it looks for	Typical situation
PGT-A	Extra or missing whole chromosomes (aneuploidy)	General embryo screening during IVF; often discussed with older patients or those with repeated IVF failure or miscarriage
PGT-M	A specific single-gene condition known to run in the family	When one or both parents carry a gene variant for a condition such as thalassemia or cystic fibrosis
PGT-SR	Structural chromosome rearrangements, such as translocations	When a parent has a known balanced translocation or similar rearrangement

Some clinics combine PGT-A with PGT-M or PGT-SR when both are relevant. The choice of test should follow a clinical discussion, not a default package.

Who may benefit from PGT-A — and who may not

PGT-A is not recommended for every IVF patient. Professional guidance generally supports discussing it in specific situations rather than offering it universally. It may be more relevant if you:

• Are older, since the proportion of aneuploid embryos tends to rise with age.
• Have a history of recurrent pregnancy loss, where aneuploidy is a common contributing factor.
• Have had repeated IVF cycles without implantation, after other causes have been reviewed.
• Have several embryos and want more information to help prioritize which to transfer.
• Have a previous pregnancy or pregnancy loss known to have been aneuploid.

It may be less clearly beneficial if you:

• Have very few embryos, because testing can reduce the number available for transfer.
• Are younger with a good prognosis and no history suggesting higher aneuploidy risk.
• Prefer to avoid the possibility of losing embryos to the testing process.
• Have a mosaic or uncertain result that could complicate decision-making.

These are general considerations, not eligibility rules. Your own situation should be assessed by your treating clinician.

How PGT-A fits into an IVF cycle

1. Ovarian stimulation and egg retrieval — standard IVF steps.
2. Fertilization and embryo culture — embryos grow in the lab for several days, often to the blastocyst stage.
3. Embryo biopsy — a small number of cells are removed from the trophectoderm (the outer layer that becomes the placenta). This is a lab procedure, not a treatment for the embryo.
4. Sample analysis — the cells are tested for chromosome number. Some clinics send samples to a partner laboratory; others use an in-house lab.
5. Embryo freezing and storage — because testing takes time, embryos are usually frozen and transferred in a later cycle.
6. Results discussion — you and your clinician review which embryos are available and how to proceed.
7. Transfer — one or more embryos may be transferred, depending on your plan and clinic guidance.

Timelines vary. Ask your clinic how long testing takes, how embryos are stored, and what happens if results are inconclusive.

Limitations and uncertainties to understand

• It is a screening test. A low-risk result does not guarantee a chromosomally normal pregnancy or a healthy child.
• Mosaic results. Some embryos show a mix of normal and abnormal cells. These results can be difficult to interpret, and policies on transferring mosaic embryos vary.
• Embryo loss. Biopsy and freezing can reduce the number of embryos available for transfer. Not every embryo survives the process.
• No improvement guarantee. Studies have not consistently shown that PGT-A improves live birth rates for all patients. It may reduce miscarriage risk in some groups, but it does not treat infertility itself.
• Technical limits. PGT-A does not detect all genetic conditions, and it cannot assess non-chromosomal causes of implantation failure.
• Cost and access. PGT-A adds laboratory and biopsy costs. These vary by clinic and are not covered here.

Alternatives and add-ons to discuss

Depending on your situation, your clinician may discuss:

• IVF without PGT-A — transferring untested embryos, with standard ultrasound and, where appropriate, other screening during pregnancy.
• PGT-M or PGT-SR — if a specific inherited condition or structural rearrangement is relevant.
• Embryo grading — a visual assessment that does not test chromosomes but can inform transfer decisions.
• Donor eggs or sperm — in some cases, this changes the aneuploidy risk profile.
• Prenatal testing — such as chorionic villus sampling or amniocentesis, which can confirm chromosome status during pregnancy.

No single option is right for everyone. The goal is to match the test to your question, not to add tests by default.

How PGT-A is discussed in Thailand

Thailand has a well-established IVF sector serving international patients, and PGT-A is offered at many clinics. However, practices differ. Some clinics offer PGT-A routinely to certain age groups; others discuss it case by case. Laboratory arrangements — whether testing is done in-house or through a partner lab — also vary, and this can affect turnaround time and how results are reported.

Because regulations, clinic policies, and laboratory practices can change, treat any specific claim about availability, eligibility, or process as something to verify directly with the clinic you are considering. For general guidance on preparing for treatment in Thailand, see our international patients page and PGT in Thailand overview.

Questions to ask a clinic before deciding

• Do you recommend PGT-A for my situation, and why or why not?
• What exactly does your PGT-A test screen for, and what does it not detect?
• Is testing done in your laboratory or sent elsewhere? Who analyzes the samples?
• How do you handle mosaic or inconclusive results?
• What proportion of embryos typically remain available for transfer after biopsy and freezing at your clinic?
• What are the additional costs, and what do they include?
• How long does testing take, and how are embryos stored in the meantime?
• What are my alternatives if I choose not to test?
• Who will explain the results to me, and in what language?
• What follow-up or prenatal testing do you recommend after transfer?

Next-step checklist

1. Clarify your own reasons for considering PGT-A — what question are you trying to answer?
2. Ask your clinician whether PGT-A is likely to change your treatment plan.
3. Request written information about the test, its limits, and the clinic’s laboratory arrangements.
4. Ask about costs, timelines, and what happens to embryos that are not transferred.
5. Consider a second opinion if the recommendation feels routine rather than personalized.
6. Review our guides and FAQ for more context on IVF and PGT decisions.

PGT-A can provide useful information in some situations, but it is one part of a larger decision. The most reliable next step is a direct conversation with a qualified clinician who can review your history and explain what testing can and cannot do for you.

Frequently asked questions

Is PGT-A the same as PGT-M or PGT-SR?

No. PGT-A screens for extra or missing whole chromosomes (aneuploidy). PGT-M looks for a specific single-gene condition known to run in a family. PGT-SR looks for structural chromosome rearrangements such as translocations. They answer different questions and may be used together in some cases.

Does PGT-A guarantee a healthy baby?

No. PGT-A is a screening test. A low-risk result reduces but does not eliminate the chance of aneuploidy, and it cannot predict implantation, pregnancy, or child health. It does not detect all genetic conditions.

Who is usually offered PGT-A?

It is often discussed with patients who are older, have a history of recurrent pregnancy loss or repeated IVF failure, or have several embryos and want more information before transfer. It is not universally recommended, and eligibility is a clinical decision.

Can PGT-A results be uncertain?

Yes. Some embryos show mosaic results, where different cells have different chromosome numbers. These can be difficult to interpret, and clinic policies on transferring mosaic embryos vary. Ask your clinic how they handle uncertain results.

What should I ask a clinic in Thailand about PGT-A?

Ask whether they recommend it for your situation, what the test screens for, whether testing is done in-house or sent to a partner lab, how mosaic results are handled, what the additional costs are, how long results take, and what alternatives exist if you choose not to test.

Continue your research

• International patient guide
• PGT in Thailand overview
• PGT and IVF guides

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.