When couples explore preimplantation genetic testing (PGT) during IVF, one of the first questions is often: What is the difference between PGT-A, PGT-M and PGT-SR?

Although all three are forms of preimplantation genetic testing, they are designed to answer different genetic questions. PGT-A focuses on chromosome number, PGT-M is used for specific single-gene conditions, and PGT-SR is designed for certain structural chromosome rearrangements.

Understanding these differences can help patients have a more informed conversation with their fertility specialist about whether genetic testing may be appropriate for their IVF treatment.

Key Takeaways

• PGT-A evaluates embryos for abnormalities in chromosome number.
• PGT-M tests for a specific known single-gene disorder.
• PGT-SR evaluates embryos when a parent has certain structural chromosome rearrangements.
• The right test depends on the individual's medical, reproductive and genetic circumstances.

What Is PGT?

Preimplantation Genetic Testing is performed on embryos created through IVF.

During the process, embryos develop in the laboratory until the appropriate stage for biopsy. A small sample of cells can then be collected and analyzed using the relevant genetic testing method.

The embryo is generally frozen while testing is completed.

PGT is not one single test. Instead, it is an umbrella term covering different testing approaches, including:

• PGT-A
• PGT-M
• PGT-SR

Each test has a different purpose.

PGT-A: Testing for Chromosome Number

PGT-A stands for Preimplantation Genetic Testing for Aneuploidy.

Aneuploidy means an embryo has an abnormal number of chromosomes.

Humans normally have 46 chromosomes arranged in 23 pairs. Changes in chromosome number can affect embryo development and pregnancy outcomes.

PGT-A can provide information about the chromosome number of cells sampled from an embryo.

When may PGT-A be considered?

A fertility specialist may discuss PGT-A in selected IVF circumstances, taking factors such as:

• Maternal age
• Previous reproductive history
• Previous IVF outcomes
• Number of embryos available
• Overall fertility circumstances

into consideration.

However, PGT-A is not automatically recommended for every IVF patient.

The American Society for Reproductive Medicine states that the value of PGT-A as a universal screening test for all IVF patients has not been established.

PGT-M: Testing for a Specific Genetic Condition

PGT-M stands for Preimplantation Genetic Testing for Monogenic Disorders.

Unlike PGT-A, which examines chromosome number, PGT-M is designed to investigate a specific single-gene condition.

For example, PGT-M may be considered when a couple has a known risk of passing a particular inherited condition to their child.

Potential examples include certain forms of:

• Thalassemia
• Cystic fibrosis
• Sickle cell disease
• Other inherited single-gene disorders

The specific condition needs to be identified so that the appropriate testing strategy can be developed.

Why is genetic counselling important?

PGT-M can be technically complex because testing is designed around a particular genetic condition or variant.

Genetic counselling can help patients understand:

• Their inheritance pattern
• The potential reproductive risk
• What PGT-M can and cannot detect
• Possible embryo results
• Alternative reproductive options

PGT-M should therefore be approached as part of a coordinated fertility and genetics assessment.

PGT-SR: Testing for Structural Chromosome Rearrangements

PGT-SR stands for Preimplantation Genetic Testing for Structural Rearrangements.

This test may be considered when one of the prospective parents carries a structural chromosome rearrangement.

Examples can include certain:

• Translocations
• Inversions

A person carrying a chromosome rearrangement may be healthy, but the rearrangement can affect the chromosome balance of embryos.

PGT-SR can provide additional information about embryos in these circumstances.

PGT-A vs PGT-M vs PGT-SR

The key difference is what the test is designed to look for.

How Do You Know Which PGT Test You Need?

There is no single PGT test that is suitable for everyone.

Your fertility specialist may first evaluate your reproductive and genetic history.

The decision may involve:

Your Family History

If there is a known inherited condition in your family, PGT-M may be discussed.

Your Genetic Test Results

If you or your partner have a known chromosome rearrangement, PGT-SR may be relevant.

Your Reproductive History

Previous IVF outcomes, pregnancy losses and other reproductive factors may influence whether PGT-A is discussed.

Your Age

Age is associated with changes in the likelihood of embryo aneuploidy, but age alone does not automatically mean PGT-A is appropriate.

Number of Embryos

The potential value of testing also depends on how many embryos develop and become available for biopsy.

Can You Have PGT-A and PGT-M Together?

In some circumstances, more than one genetic question may need to be addressed.

For example, a couple may have a known inherited single-gene condition while also considering chromosome testing.

Whether combined testing is appropriate depends on the individual clinical situation and laboratory capabilities.

Your fertility specialist and genetics team can explain which testing strategy is appropriate.

How Are PGT Samples Obtained?

PGT takes place after embryos are created through IVF.

The general process includes:

1. Ovarian stimulation
Medication is used to stimulate the ovaries.

2. Egg retrieval
Mature eggs are collected.

3. Fertilization
Eggs are fertilized in the laboratory.

4. Embryo culture
Embryos are monitored as they develop.

5. Blastocyst development
Embryos that develop appropriately may reach the blastocyst stage.

6. Embryo biopsy
A small sample of cells is collected.

7. Genetic analysis
The sample is analyzed using the selected PGT method.

8. Embryo transfer planning
Once results are available, the fertility team discusses the next steps.

What Happens After PGT?

After testing, the results are reviewed by the appropriate clinical team.

Depending on the type of PGT, results can provide information about whether embryos meet the criteria being evaluated.

However, a PGT result should never be interpreted as a guarantee of pregnancy.

Other factors remain important, including:

• Uterine health
• Embryo development
• Maternal age
• Sperm factors
• Endometrial factors
• Overall reproductive health

Your fertility specialist will consider the complete clinical picture when discussing embryo transfer.

Does PGT Guarantee a Healthy Baby?

No.

This is one of the most important things patients should understand.

PGT is designed to investigate a specific genetic or chromosomal issue. It does not screen for every possible disease, developmental condition or health problem.

Even an embryo with a favorable PGT result may not result in pregnancy or a live birth.

Appropriate prenatal screening and/or diagnostic testing may still be recommended after pregnancy.

Is PGT Necessary for Every IVF Patient?

No.

Some couples may have a clear medical or genetic reason to consider PGT, while others may not benefit enough from testing to justify adding it to their IVF treatment.

For this reason, PGT should be discussed as an individualized treatment decision.

The goal should not be to perform more testing simply because it is available. Instead, patients and clinicians should consider whether the information gained could meaningfully influence reproductive decision-making.

PGT in Dubai: What Should Patients Consider?

If you're researching PGT testing in Dubai, don't choose a treatment based only on the name of the test.

Ask your fertility clinic:

• Which PGT test is being recommended?
• Why is it appropriate for my situation?
• What exactly will the test detect?
• Do I need genetic counselling?
• How many embryos are expected to reach the testing stage?
• What happens if no embryo is suitable for transfer?
• How are uncertain or mosaic results interpreted?
• What additional prenatal testing may be recommended?

These questions can help you understand the purpose and limitations of testing before making a decision.

PGT at Almond Blossoms Fertility & Wellbeing Centre

At Almond Blossoms Fertility & Wellbeing Centre in Dubai, PGT is offered as part of specialized fertility care.

The clinic provides options including:

• PGT-A
• PGT-M
• PGT-SR

The appropriate testing approach depends on the patient's individual reproductive and genetic circumstances.

For patients who want to learn more about the available options, you can link this article to your main service page using:

Final Thoughts

PGT-A, PGT-M and PGT-SR may sound similar, but they serve very different purposes.

PGT-A focuses on chromosome number.
PGT-M focuses on specific single-gene disorders.
PGT-SR focuses on certain structural chromosome abnormalities.

The right option depends on the individual's genetic background, reproductive history and IVF treatment goals.

If you're considering preimplantation genetic testing in Dubai, discussing your circumstances with a fertility specialist can help you understand whether PGT may be appropriate and which type of testing is relevant.

FAQs

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

PGT-A evaluates embryos for chromosome-number abnormalities, while PGT-M is designed to test for a specific single-gene disorder.

What does PGT-SR test for?

PGT-SR is used to evaluate embryos when there is a known structural chromosome rearrangement, such as certain translocations or inversions.

Which PGT is best?

There is no universally “best” PGT test. The appropriate test depends on the genetic or reproductive concern being investigated.

Is PGT done before embryo transfer?

Yes. PGT is performed on embryo biopsy samples before an embryo is selected for transfer.

Does PGT increase IVF success?

The potential benefit varies according to the patient and the type of PGT. PGT should not be presented as a guarantee of increased IVF success.

Can PGT detect Down syndrome?

PGT-A can assess embryos for chromosome-number abnormalities involving chromosome 21, but PGT is not a guarantee that a baby will be free of Down syndrome or other health conditions. Appropriate prenatal testing remains important.

Is PGT-M only for serious genetic diseases?

PGT-M is designed for specific monogenic conditions. Whether it is appropriate depends on the particular genetic condition and individual reproductive circumstances.

Is genetic counselling needed before PGT?

Genetic counselling may be particularly important when PGT-M or PGT-SR is being considered because patients need to understand the genetic condition, inheritance pattern and possible testing outcomes.