PGT-A vs PGT-M in Thailand: Which Test Is Right for You?

PGT-A and PGT-M are two types of preimplantation genetic testing used during IVF. PGT-A screens embryos for extra or missing chromosomes, while PGT-M looks for a specific inherited condition known to run in your family. The right test depends on your medical history, family history, and what you and your clinician aim to learn. Neither test guarantees a healthy pregnancy or baby, and not every patient needs either test. In Thailand, availability and laboratory protocols vary by clinic, so you will need to confirm details directly with your chosen provider.

At a glance: PGT-A vs PGT-M

• PGT-A checks the number of chromosomes in an embryo. It is often considered when age or history suggests a higher chance of chromosomal issues.
• PGT-M looks for a specific gene change linked to a known inherited condition in the family.
• PGT-A is broader but less specific; PGT-M is highly targeted.
• Both require an IVF cycle and a biopsy of embryo cells.
• Neither test can guarantee a successful pregnancy or a child without health issues.

What is PGT-A?

PGT-A stands for preimplantation genetic testing for aneuploidy. Aneuploidy means an embryo has an abnormal number of chromosomes—either too many or too few. Chromosome number errors are common in human embryos and become more frequent with increasing maternal age. PGT-A is used to identify embryos with a normal number of chromosomes (euploid) versus those with an abnormal number (aneuploid).

PGT-A does not look for specific gene mutations. It is a screening test, not a diagnostic test for a particular disease. It may be offered to patients who have experienced recurrent pregnancy loss, repeated IVF failure, or who are of advanced maternal age. However, the use of PGT-A remains debated, and it is not universally recommended for all IVF patients. Some embryos with abnormal results can sometimes self-correct, and some normal embryos may fail to implant for other reasons.

What is PGT-M?

PGT-M stands for preimplantation genetic testing for monogenic disorders. Monogenic means caused by a single gene. PGT-M is used when there is a known risk of passing on a specific inherited condition, such as cystic fibrosis, spinal muscular atrophy, or Huntington’s disease. It requires that the exact gene mutation in the family has been identified through genetic testing of the parents or an affected family member.

PGT-M is highly targeted. The laboratory builds a custom test to look for that specific mutation in the embryo. This means PGT-M is not a general screen; it is only useful when the mutation is known. Without prior genetic testing, PGT-M cannot be performed. PGT-M can reduce the chance of implanting an embryo affected by the condition, but it does not eliminate all risks, and it cannot guarantee a healthy child.

How do PGT-A and PGT-M differ in purpose?

The core difference is scope. PGT-A looks at all chromosomes broadly to detect numerical abnormalities. PGT-M looks at one specific gene to detect a known familial mutation. PGT-A is often used when there is no known inherited condition but there is a concern about chromosomal errors. PGT-M is used when a specific inherited condition is known to be present in the family.

Another difference is the starting point. PGT-A can be done without prior genetic testing of the parents. PGT-M requires prior identification of the mutation, usually through a blood test of the parents or a relative. This makes PGT-M a more personalized and labor-intensive process.

When might each test be considered?

PGT-A may be discussed if you are of advanced maternal age, have a history of recurrent miscarriage, or have had multiple unsuccessful IVF cycles. Some clinics also offer it as an optional add-on for any IVF cycle, though its benefit for all patients is not firmly established.

PGT-M is considered when you or your partner carry a known genetic mutation that could be passed on, or when you already have a child affected by a genetic condition. It is also an option for couples who are both carriers of the same recessive condition. In these cases, PGT-M can help select embryos that are not affected by the condition.

It is important to note that neither test is a requirement for IVF. Many healthy babies are born from IVF without any genetic testing. The decision should be made with a genetic counselor and your fertility doctor, based on your individual circumstances.

How are the laboratory processes different?

Both PGT-A and PGT-M begin with an IVF cycle, where eggs are retrieved and fertilized to create embryos. The embryos are cultured for a few days until they reach the blastocyst stage. At that point, a few cells are removed from the outer layer (trophectoderm) in a procedure called a biopsy. The biopsied cells are sent to a genetics laboratory for analysis.

For PGT-A, the lab uses techniques such as next-generation sequencing (NGS) to count the chromosomes. This process can be done relatively quickly and does not require a custom probe.

For PGT-M, the lab must first develop a personalized test that can detect the specific mutation. This often involves building a probe using DNA from the parents or a reference sample. The process takes longer and requires more specialized expertise. In some cases, PGT-M may be combined with PGT-A to also check chromosome number, but this is a separate decision.

In Thailand, not all clinics offer PGT-M, and those that do may have different laboratory protocols. You will need to ask your clinic about their experience and whether they perform the test in-house or send samples abroad.

What are the limitations of each test?

PGT-A can sometimes produce results that are difficult to interpret, such as mosaicism, where an embryo has a mix of normal and abnormal cells. The clinical significance of mosaicism is not fully understood, and some mosaic embryos can lead to healthy pregnancies. PGT-A also cannot detect all genetic problems; it only looks at chromosome number, not gene mutations or structural rearrangements.

PGT-M is limited to the specific mutation it was designed to detect. It cannot rule out other genetic conditions that were not tested for. It also requires that the mutation is known and that a reliable test can be built. In some cases, the test may not be informative for all embryos. Like PGT-A, PGT-M cannot guarantee a successful pregnancy or a child free of all health issues.

Both tests involve a biopsy, which carries a small risk of damage to the embryo, though this risk is considered low. Neither test improves the quality of the embryos themselves; they only provide information to help select which embryos to transfer.

How to decide which test is right for you

The choice between PGT-A and PGT-M is not a simple either/or. Some patients may be advised to have PGT-M alone, PGT-A alone, both, or neither. The decision should be based on your medical and family history, the reason for your IVF, and your goals.

Start by discussing your family history with your doctor. If you have a known genetic condition in the family, PGT-M may be relevant. If you have a history of miscarriage or are older, PGT-A might be discussed. A genetic counselor can help you understand your risks and the implications of testing.

Ask your clinic about their experience with each test, their laboratory partners, and how they handle results. Because PGT is a rapidly evolving field, protocols and availability can change. What is offered today may differ from what is available next year.

Questions to ask your clinic in Thailand

• Do you offer PGT-A and PGT-M? If not, do you refer to another clinic?
• What laboratory do you use for genetic testing? Is it in Thailand or overseas?
• What is your experience with PGT-M for my specific condition?
• How do you handle mosaic results from PGT-A?
• What are the costs involved? (Ask for a detailed breakdown.)
• What are the success rates for my age and diagnosis? (Understand how they define success.)
• What are the risks and limitations of each test?
• How long does it take to get results?
• Do you provide genetic counseling before and after testing?

Next steps

If you are considering PGT-A or PGT-M in Thailand, begin by gathering your personal and family medical history. Speak with a genetic counselor if you have a known inherited condition. Then consult with a fertility clinic that offers the test you are interested in. Remember that PGT is a tool, not a guarantee. It can provide useful information, but it does not replace a thorough discussion with your healthcare team about your individual chances and options.

For more general information about PGT in Thailand, explore our PGT in Thailand guide. You can also browse our guides and FAQ for additional support.

Frequently asked questions

Can I have PGT-M without PGT-A?

Yes, PGT-M can be performed alone. Some clinics may recommend combining it with PGT-A to also check chromosome number, but this is a separate decision based on your situation.

Is PGT-A always necessary for IVF?

No. PGT-A is not required for all IVF cycles. It may be offered in certain cases, such as advanced maternal age or recurrent miscarriage, but its benefit for all patients is still debated. Discuss with your doctor whether it is appropriate for you.

What is the difference between PGT-A and PGT-M in terms of what they detect?

PGT-A detects extra or missing chromosomes (aneuploidy) across all chromosomes. PGT-M detects a specific gene mutation that is known to run in your family. PGT-A is a broad screen; PGT-M is a targeted test.

Does PGT guarantee a healthy baby?

No. PGT can provide information about embryos, but it cannot guarantee a successful pregnancy or a child without health issues. Other factors, including maternal health and embryo quality, also play a role.

How do I know if I need PGT-M?

PGT-M is considered when there is a known inherited condition in your family or if you and your partner are carriers of the same genetic condition. A genetic counselor can help assess your risk and whether PGT-M is appropriate.

Continue your research

• PGT in Thailand overview
• PGT and IVF guides
• Frequently asked questions

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.