What Is PGT-A and How Does It Work?

If you are considering IVF and have heard the term PGT-A, you may be wondering what it actually tests and whether it could be useful for you. PGT-A is a genetic screening test used during IVF to check embryos for an abnormal number of chromosomes before an embryo is transferred.

PGT-A stands for Preimplantation Genetic Testing for Aneuploidy. “Aneuploidy” means that a cell has too many or too few chromosomes.

The test involves taking a small sample of cells from an embryo, usually when it reaches the blastocyst stage, and analyzing those cells in a genetics laboratory. The results can help your fertility specialist understand which embryos have the expected chromosome number and which may have chromosomal abnormalities.

However, PGT-A is not a guarantee of pregnancy or a healthy baby, and it is not automatically recommended for everyone undergoing IVF. Whether it makes sense for you depends on your age, reproductive history, embryo development, and individual circumstances.

What Is PGT-A?

PGT-A is a screening test that checks IVF embryos for abnormalities in chromosome number.

Most human cells normally contain 46 chromosomes, arranged in 23 pairs. One set comes from the egg and one from the sperm.

When an embryo has an extra or missing chromosome, it is described as aneuploid. An embryo with the expected chromosome number is generally described as euploid. Chromosomal abnormalities can be associated with implantation failure, miscarriage, or certain genetic conditions.

PGT-A is therefore used as an embryo-selection tool. It provides additional genetic information that can be considered alongside the embryo’s development and appearance when deciding which embryo may be suitable for transfer.

How Does PGT-A Work During IVF?

PGT-A cannot be performed independently of IVF because the embryos need to be created in the laboratory first. The general process involves several stages.

1. Ovarian stimulation and egg retrieval

During IVF, medications are used to stimulate the ovaries so that multiple eggs can mature.

Your fertility specialist monitors your response and then performs an egg retrieval, where mature eggs are collected.

2. Fertilisation

The eggs are fertilised with sperm in the laboratory.

Depending on your circumstances, this may involve conventional IVF or ICSI (intracytoplasmic sperm injection), where a single sperm is injected directly into an egg.

You can learn more through Almond Blossoms’ IVF & ICSI treatment.

3. Embryo development

After fertilisation, the embryos are monitored as they develop in the laboratory.

PGT-A is commonly performed when embryos reach the blastocyst stage, typically around day 5 or 6 of development. 

4. Embryo biopsy

An embryologist carefully removes a small number of cells from the embryo’s outer layer.

This procedure is called an embryo biopsy. The cells are sent to a specialist genetics laboratory for analysis.

5. Genetic analysis

The laboratory analyzes the sampled cells to determine whether the embryo appears to have the expected number of chromosomes.

The embryo itself is generally not transferred immediately while testing is being completed. Embryos may be cryopreserved, depending on the treatment plan.

6. Reviewing the PGT-A results

Once the results are available, your fertility specialist explains what they mean and discusses which embryos may be appropriate for transfer.

This is an important stage because PGT-A results are not always simply “normal” or “abnormal.”

What Do PGT-A Results Mean?

Understanding the terminology can make your results much less confusing.

Euploid embryo

A euploid result means the tested cells showed the expected chromosome number.

A euploid embryo may therefore be considered for transfer, depending on the complete clinical picture.

Aneuploid embryo

An aneuploid result means the tested cells showed an abnormal number of chromosomes.

These embryos generally have a lower potential for successful implantation and may be associated with miscarriage or chromosomal conditions.

Mosaic embryo

A mosaic result means that the tested sample contains a mixture of cells with different chromosome findings.

This result can be particularly difficult emotionally because it does not always provide a simple yes-or-no answer.

Research and clinical practice regarding mosaic embryos are evolving, and different clinics may have different approaches to reporting and considering them for transfer. A fertility specialist should explain your specific result rather than assuming that every mosaic result has the same significance. 

Who Might Consider PGT-A?

People also ask: Who should have PGT-A?

There is no single age or diagnosis that automatically means you should have PGT-A.

Your fertility specialist may discuss it as an option based on factors such as:

• Your reproductive age
• Previous miscarriage history
• Previous unsuccessful IVF treatment
• The number and development of embryos obtained
• Your overall reproductive history
• Chromosomal or genetic concerns
• Your personal priorities regarding embryo selection

Age can be relevant because the likelihood of chromosomal abnormalities in embryos generally changes with reproductive age. However, PGT-A is not automatically beneficial for every person over a particular age.

Current evidence does not support presenting PGT-A as a universal way to increase the chance of having a baby for everyone undergoing IVF. The Human Fertilisation and Embryology Authority (HFEA), for example, notes that PGT-A can reduce miscarriage risk in some circumstances but may also reduce the number of embryos available for transfer. 

What Are the Benefits and Limitations of PGT-A?

PGT-A can provide useful information, but it is important to understand both sides before deciding.

Potential benefits

PGT-A may:

• Provide additional information about embryo chromosome status
• Help identify embryos with a typical chromosome number
• Help avoid transferring an embryo identified as aneuploid
• Potentially reduce the chance of miscarriage associated with chromosomal abnormalities in some patients
• Help your fertility team make a more informed embryo-transfer strategy

For some couples, having additional information can also reduce uncertainty when deciding which embryo to transfer.

Important limitations

PGT-A does not:

• Guarantee implantation
• Guarantee pregnancy
• Guarantee a healthy baby
• Detect every possible genetic or developmental condition
• Replace routine prenatal testing
• Guarantee that an embryo classified as euploid will result in a live birth

The test examines a small sample of cells rather than every cell in the embryo. Results can occasionally be inaccurate, and mosaic results can make interpretation more complicated. 

PGT-A can also mean additional laboratory procedures, time, and cost. In some cases, testing may result in fewer embryos being available for transfer.

For these reasons, PGT-A should be considered as part of a broader fertility treatment plan rather than as a guaranteed method of improving IVF outcomes.

Does PGT-A Increase IVF Success Rates?

People also ask: Does PGT-A improve IVF success?

PGT-A can help identify embryos with an expected chromosome number, and evidence suggests it may reduce miscarriage in some groups. However, it does not mean that every patient who uses PGT-A will have a higher live-birth rate.

The HFEA currently notes that PGT-A is primarily a selection tool and that high-quality evidence has not shown an improvement in the chance of having a baby for most IVF patients. It also notes evidence for reduced miscarriage in some circumstances. This distinction is important.

A test may help your specialist select between available embryos without necessarily increasing the total number of babies that can result from an IVF cycle.

Your specialist should therefore consider your individual circumstances before recommending PGT-A.

PGT-A in Dubai: What Should You Discuss With Your Fertility Specialist?

If you are considering PGT-A in Dubai, don’t make the decision based only on age, online success-rate claims, or another person’s IVF experience.

During your consultation, ask:

1. Why might PGT-A be appropriate in my case?
2. How many embryos are likely to reach the blastocyst stage?
3. What happens if my embryos have mosaic results?
4. How will my embryos be stored while testing is completed?
5. What are the additional costs involved?
6. How will PGT-A results affect my embryo-transfer plan?
7. What other genetic testing might be relevant to me?

At Almond Blossoms Fertility & Wellbeing Center in Dubai Healthcare City, fertility decisions can be discussed alongside emotional and psychological support. This can be particularly valuable when genetic testing produces difficult or unexpected results.

PGT-A decisions can involve more than laboratory numbers. Some patients experience anxiety while waiting for results, uncertainty about embryo selection, or grief when fewer embryos are available than expected. Having access to fertility-focused psychological support can provide another layer of care during this process.