At a glance
PGT-A can screen embryos for certain chromosome number changes, but it cannot guarantee a healthy pregnancy or a healthy child. This guide explains what PGT-A does and does not tell you, and what to ask a clinic in Thailand.
PGT-A (preimplantation genetic testing for aneuploidy) is a laboratory test performed on a small sample of cells taken from an embryo during IVF. It can screen for extra or missing copies of whole chromosomes, a condition called aneuploidy. It cannot tell you whether an embryo will implant, whether a pregnancy will continue, or whether a child will be healthy. It is a screening test, not a guarantee, and it is not necessary or suitable for every patient. If you are considering PGT-A in Thailand, the most useful step is to understand its scope and limits before you decide.
At a glance
- PGT-A looks at chromosome number, not at specific genes or all possible genetic conditions.
- It is a screening test, so results are probabilistic, not absolute.
- A “normal” result does not guarantee implantation, pregnancy, or a healthy child.
- An “abnormal” result does not always mean the embryo could never produce a healthy pregnancy; some findings are uncertain.
- PGT-A is not the same as PGT-M or PGT-SR, which look for different things.
- Whether PGT-A is appropriate depends on your history, age, embryo availability, and clinic guidance.
What PGT-A screens for
PGT-A is designed to detect whole-chromosome aneuploidy, meaning an embryo has an extra or missing copy of one or more chromosomes. Human cells usually have 46 chromosomes in 23 pairs. Aneuploidy can involve any chromosome, and some aneuploidies are more common than others. PGT-A does not routinely look for single-gene mutations, small deletions or duplications, or structural rearrangements. Those are addressed by different tests.
The test is usually performed on a few cells removed from an embryo, typically at the blastocyst stage. The sample is analysed in a laboratory, and the result is reported as a classification, such as euploid (no aneuploidy detected), aneuploid (aneuploidy detected), or sometimes mosaic (a mixture of cells with different chromosome numbers). Some reports also include a category for inconclusive or no result.
What PGT-A cannot tell you
PGT-A cannot confirm that an embryo will implant or that a pregnancy will result in a live birth. It cannot rule out all genetic conditions, because it does not examine every gene or every possible chromosome change. It cannot predict childhood health, development, or future medical conditions. It also cannot tell you whether an embryo will be affected by conditions caused by factors other than chromosome number, such as environmental influences or multifactorial conditions.
In addition, PGT-A cannot guarantee that the embryo chosen for transfer is the “best” one in every respect. Embryo quality, uterine environment, and many other factors influence outcomes. A euploid result reduces the probability of certain chromosome-related issues, but it does not eliminate them.
PGT-A, PGT-M, and PGT-SR: different tests, different questions
PGT-A is one of several preimplantation genetic tests. PGT-M (preimplantation genetic testing for monogenic disorders) looks for a specific inherited condition caused by a single gene, such as cystic fibrosis or spinal muscular atrophy. PGT-SR (preimplantation genetic testing for structural rearrangements) looks for chromosome structural changes, such as translocations, that may be present in a parent. Each test requires different laboratory methods and answers a different question. If you are considering PGT in Thailand, ask which test is being recommended and why.
How PGT-A results are interpreted
PGT-A results are usually reported as a classification. A euploid result means no aneuploidy was detected in the sampled cells. An aneuploid result means aneuploidy was detected. A mosaic result means the sample contained a mixture of euploid and aneuploid cells. Mosaic results can be difficult to interpret because the proportion and type of mosaic cells matter, and the clinical significance is not always clear. Some clinics may consider transferring mosaic embryos after counselling, while others may not. An inconclusive result means the test did not provide a clear answer, and repeat testing or another approach may be discussed.
It is important to understand that a result applies to the sampled cells, not necessarily to the whole embryo. The embryo may be mosaic even if the sample appeared uniform. This is one reason why PGT-A is a screening test, not a diagnostic test for the embryo as a whole.
Limitations and uncertainties
PGT-A has technical limitations. The sample size is small, and the test may miss some chromosome changes or detect changes that are not present in the whole embryo. Some embryos may be classified as mosaic, which creates uncertainty about transfer decisions. The test does not detect all genetic conditions, and it does not assess non-chromosomal causes of pregnancy loss or implantation failure. It also does not improve the quality of an embryo or change the underlying reasons for infertility.
Another limitation is that PGT-A requires embryos to be created and cultured to a suitable stage, which may not be possible for every patient. It also adds cost and time to an IVF cycle. Whether the potential information is worth these trade-offs is a personal decision that should be discussed with a qualified clinician.
Who might consider PGT-A
PGT-A is not recommended for everyone. It may be discussed with patients who have a history of recurrent pregnancy loss, repeated implantation failure, or advanced maternal age, or when there are other clinical reasons. However, guidelines and professional opinions vary, and the evidence for benefit in different groups is not uniform. Some patients may choose PGT-A to gain information, while others may decide against it. There is no single right answer.
If you are considering PGT-A in Thailand, ask the clinic about their experience, their laboratory methods, and how they interpret and report results. Ask what they do with mosaic or inconclusive results, and what alternatives exist if you decide not to test.
Questions to ask a clinic in Thailand
- Which PGT test are you recommending, and why?
- What does the test screen for, and what does it not screen for?
- How do you report mosaic and inconclusive results?
- What are the possible next steps if the result is abnormal or uncertain?
- What are the costs, and what do they include?
- What are the risks of the biopsy procedure?
- How do you counsel patients about the limitations of PGT-A?
- What alternatives are available if we decide not to do PGT-A?
Next steps for international patients
Before travelling to Thailand for IVF with PGT-A, gather information from the clinic in writing. Ask for a clear explanation of the test, its limitations, and the costs involved. Confirm what documents you need, what visas or entry requirements apply, and how long you may need to stay. These details can change, so verify them with the clinic and relevant authorities. It is also wise to ask about follow-up care and how results will be communicated to you.
You can learn more about PGT in Thailand in our PGT in Thailand guide, browse other patient guides, or check our FAQ for general information. Always discuss your individual situation with a qualified healthcare provider.
Frequently asked questions
Does a normal PGT-A result guarantee a healthy baby?
No. PGT-A is a screening test that looks for extra or missing whole chromosomes in a small sample of cells. A normal result reduces the chance of certain chromosome-related issues, but it cannot guarantee implantation, a continuing pregnancy, or a healthy child. Other genetic and non-genetic factors can still affect outcomes.
What is the difference between PGT-A and PGT-M?
PGT-A screens for whole-chromosome aneuploidy, such as an extra or missing chromosome. PGT-M looks for a specific inherited condition caused by a single gene. They are different tests used for different purposes, and sometimes both may be considered.
Can PGT-A tell me if my embryo is mosaic?
PGT-A can sometimes detect mosaicism, which means the embryo has a mixture of cells with different chromosome numbers. However, the result applies only to the sampled cells, and the clinical significance of mosaicism can be uncertain. Your clinic should explain what a mosaic result means for your situation.
Is PGT-A recommended for everyone doing IVF?
No. PGT-A is not universally recommended. It may be discussed for specific situations, such as recurrent pregnancy loss or advanced maternal age, but guidelines vary and the evidence is not uniform. Whether to use PGT-A is a personal decision to discuss with your clinician.
What should I ask a clinic in Thailand about PGT-A?
Ask which test is recommended and why, what it screens for and does not screen for, how mosaic and inconclusive results are handled, what the costs include, and what alternatives exist. Also ask about the biopsy procedure, counselling, and how results will be communicated.
Continue your research
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.
Need help turning research into a shortlist?
