PGT-A vs PGT-M in Thailand: What’s the Difference?

PGT-A vs PGT-M: Understanding the Basics

If you are exploring IVF in Thailand, you may come across two common genetic tests: PGT-A and PGT-M. Both are performed on embryos before transfer, but they answer different questions. PGT-A (Preimplantation Genetic Testing for Aneuploidy) checks for the correct number of chromosomes, while PGT-M (Preimplantation Genetic Testing for Monogenic disorders) looks for specific inherited genetic conditions. This guide explains the difference to help you discuss options with your fertility team.

At a Glance: PGT-A vs PGT-M

• PGT-A: Screens embryos for chromosomal abnormalities (aneuploidy).
• PGT-M: Tests for a specific genetic disorder that runs in the family.
• Purpose: PGT-A aims to improve IVF success by selecting chromosomally normal embryos; PGT-M aims to avoid passing on a known genetic condition.
• Who it’s for: PGT-A is often considered for women of advanced maternal age or those with recurrent miscarriage; PGT-M is for couples with a known monogenic disorder.
• Method: Both require a biopsy of a few cells from the embryo, usually on day 5 or 6.

What Is PGT-A?

PGT-A, previously known as preimplantation genetic screening (PGS), checks embryos for an abnormal number of chromosomes. Humans typically have 46 chromosomes. An extra or missing chromosome is called aneuploidy. Many aneuploid embryos fail to implant or result in miscarriage. PGT-A can identify which embryos have the correct number of chromosomes, potentially helping your doctor choose the embryo most likely to lead to a successful pregnancy.

PGT-A is often recommended for:

• Women over 35, as the risk of aneuploidy increases with age.
• Couples who have experienced recurrent pregnancy loss.
• Couples with previous failed IVF cycles.
• Couples who want to reduce the risk of miscarriage due to chromosomal abnormalities.

It is important to note that PGT-A does not guarantee a pregnancy or a healthy baby. It only screens for chromosomal number abnormalities, not all genetic conditions.

What Is PGT-M?

PGT-M is used when one or both partners carry a specific genetic mutation that could cause a monogenic disorder, such as cystic fibrosis, sickle cell anemia, or Huntington’s disease. The test identifies embryos that have inherited the mutation, allowing the transfer of embryos free from that particular condition.

PGT-M is typically recommended for:

• Couples with a known genetic disorder in their family.
• Couples who are carriers of an autosomal recessive or X-linked condition.
• Couples who have had a child with a genetic disorder and wish to avoid passing it on.

PGT-M requires prior genetic testing of the parents to identify the specific mutation. The test is highly specific and does not screen for other chromosomal abnormalities unless combined with PGT-A.

Key Differences Between PGT-A and PGT-M

Aspect	PGT-A	PGT-M
Purpose	Checks for chromosomal number abnormalities	Checks for a specific genetic mutation
Who it’s for	General IVF patients, especially those with age-related risks	Couples with a known genetic disorder
Method	Biopsy of embryo cells, then analysis of chromosomes	Biopsy of embryo cells, then analysis for specific mutation
Result	Identifies embryos with normal chromosome number	Identifies embryos without the specific mutation
Limitations	Does not detect all genetic disorders	Does not detect chromosomal abnormalities unless combined with PGT-A

Can PGT-A and PGT-M Be Combined?

Yes, in some cases, PGT-A and PGT-M can be performed together on the same embryo biopsy. This is sometimes called PGT-A+PGT-M or comprehensive PGT. Combining them allows you to screen for both chromosomal abnormalities and a specific genetic mutation. However, this may increase the cost and complexity of the testing. Your fertility clinic can advise whether combined testing is appropriate for your situation.

How Are PGT-A and PGT-M Performed?

Both tests follow a similar process:

1. Ovarian stimulation and egg retrieval: Eggs are collected and fertilized with sperm in the lab.
2. Embryo culture: Embryos are grown to the blastocyst stage, usually by day 5 or 6.
3. Biopsy: A few cells are removed from the outer layer of the embryo (trophectoderm).
4. Genetic analysis: The cells are sent to a genetics lab for analysis.
5. Embryo transfer: A healthy embryo is selected for transfer, usually in a subsequent cycle.

The biopsy is performed by an embryologist, and the analysis is done in a specialized laboratory. The time required for results may vary, so ask your clinic about the expected timeline.

When Is Each Test Recommended?

Your doctor may recommend PGT-A if you have no known genetic disorder but want to reduce the risk of chromosomal abnormalities. PGT-M is recommended when there is a specific genetic condition in your family. In some cases, both tests may be suggested, especially if you are of advanced maternal age and also carry a genetic mutation.

It is essential to have genetic counseling before undergoing PGT-M to understand the implications of the results and the limitations of the test.

Questions to Ask Your Clinic

When considering PGT-A or PGT-M in Thailand, ask your fertility clinic:

• Which genetic tests do you offer, and what is the difference in your lab?
• How many embryos typically reach the biopsy stage?
• How long does it take to get results?
• What are the risks of embryo biopsy?
• What is the cost of PGT-A and PGT-M, and are they covered by any packages?
• Do you have genetic counseling available?

Next Steps

If you are deciding between PGT-A and PGT-M, start by discussing your medical history and family history with a fertility specialist. They can help you determine which test, if any, is appropriate. You may also want to consult a genetic counselor to understand the implications of testing.

For more information, explore our PGT in Thailand guide, or visit our guides section. If you have specific questions, check our FAQ page.

Frequently asked questions

What is the main difference between PGT-A and PGT-M?

PGT-A screens embryos for chromosomal abnormalities (aneuploidy), while PGT-M tests for a specific inherited genetic mutation. PGT-A is often used to improve IVF success rates, whereas PGT-M is used to avoid passing on a known genetic disorder.

Can PGT-A and PGT-M be done together?

Yes, in some cases, both tests can be performed on the same embryo biopsy. This allows screening for both chromosomal abnormalities and a specific genetic mutation. However, not all clinics may offer combined testing, and it may increase the cost.

Who should consider PGT-A?

PGT-A is often considered for women of advanced maternal age, couples with recurrent pregnancy loss, or those with previous failed IVF cycles. It may also be used to reduce the risk of miscarriage due to chromosomal abnormalities.

Who should consider PGT-M?

PGT-M is recommended for couples who are carriers of a specific genetic disorder, have a family history of a monogenic condition, or have had a child with such a condition. Genetic counseling is essential before undergoing PGT-M.

Are PGT-A and PGT-M available in Thailand?

Yes, many fertility clinics in Thailand offer PGT-A and PGT-M. However, the availability and specific protocols may vary. It is important to confirm with your chosen clinic about their genetic testing services and any associated requirements.

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.