How PGT-A Affects the Number of Embryos Available for Transfer

When you undergo IVF, the number of embryos you have can drop at several stages. PGT-A (preimplantation genetic testing for aneuploidy) is one of those stages. It screens embryos for chromosomal abnormalities before transfer. Because not all embryos will be chromosomally normal, PGT-A can reduce the number of embryos available for transfer. This article explains why that happens, what it means for your decisions, and how to plan for the possibility of needing more than one cycle.

At a Glance

• PGT-A tests embryos for chromosomal abnormalities.
• Not all embryos will be normal, so the number available for transfer may decrease.
• This reduction is part of the IVF process and can affect your timeline and decisions.
• Planning for multiple cycles can help manage expectations.

What Is PGT-A?

PGT-A is a genetic test performed on embryos created through IVF. It checks for aneuploidy, which means having an abnormal number of chromosomes. Embryos with the correct number of chromosomes (46) are considered euploid and are more likely to implant and develop normally. Embryos with missing or extra chromosomes are aneuploid and may fail to implant or result in miscarriage.

PGT-A is not a guarantee of a successful pregnancy, but it provides information that can help you and your clinic decide which embryos to transfer.

How PGT-A Reduces the Number of Usable Embryos

During IVF, you may produce several embryos. After fertilization, embryos are cultured for a few days. At the blastocyst stage, a few cells are biopsied and sent for PGT-A testing. The results typically categorize embryos as:

• Euploid: normal chromosome number, suitable for transfer.
• Aneuploid: abnormal chromosome number, generally not recommended for transfer.
• Mosaic: a mix of normal and abnormal cells, which may have reduced potential.

Because a significant proportion of embryos can be aneuploid, especially as maternal age increases, the number of embryos that are suitable for transfer may be lower than the total number of embryos you produce. This is often called embryo attrition.

What This Means for Your Decision-Making

Knowing that PGT-A can reduce the number of available embryos helps you prepare emotionally and practically. Here are some key points to consider:

• Expect attrition: It is normal for not all embryos to be normal. Discuss with your clinic what percentage of embryos typically come back as euploid for your age group.
• Transfer decisions: If you have fewer euploid embryos, you may need to decide how many to transfer in a single cycle. Your clinic will guide you based on your situation.
• Consider all options: If you have no euploid embryos, you may need to consider another IVF cycle, using donor eggs, or other alternatives. Your clinic can discuss these options with you.

Planning for Multiple Cycles

Because PGT-A can reduce the number of transferable embryos, it is wise to plan for the possibility of more than one IVF cycle. Here are some steps to consider:

1. Discuss your goals: Talk to your clinic about how many embryos you hope to have for transfer and whether you are open to multiple cycles.
2. Understand your ovarian reserve: Your age and ovarian reserve affect how many eggs you are likely to produce. This can influence the number of embryos you may get.
3. Budget and time: Multiple cycles involve additional time and cost. Ask your clinic for a breakdown of costs per cycle and any package deals.
4. Emotional preparation: The uncertainty of embryo numbers can be stressful. Consider counseling or support groups.

Questions to Ask Your Clinic

To make informed decisions, ask your clinic the following questions:

• What is the expected attrition rate from eggs to blastocysts and then to euploid embryos for someone my age?
• How many embryos do you recommend we aim for before considering transfer?
• What are the options if we have no euploid embryos?
• Are there any additional tests or procedures that might help?

Next Steps

If you are considering PGT-A, take these steps:

1. Consult with a fertility specialist to understand if PGT-A is right for you.
2. Ask for a detailed explanation of the testing process and what the results mean.
3. Plan financially and emotionally for the possibility of multiple cycles.
4. Explore resources on PGT in Thailand and general guides to help you prepare.

Remember, PGT-A is a tool to provide information, not a guarantee. The number of embryos available for transfer can be lower than expected, but this knowledge helps you make the best decisions for your family-building journey.

Frequently asked questions

Does PGT-A always reduce the number of embryos available?

Not always, but it can. PGT-A identifies embryos with chromosomal abnormalities, and those are typically not transferred. The reduction depends on factors like maternal age and embryo quality. Some patients may have many euploid embryos, while others may have few or none.

What happens if I have no euploid embryos after PGT-A?

If no embryos are euploid, your clinic will discuss options such as another IVF cycle, using donor eggs, or considering mosaic embryos. The decision depends on your individual situation and should be made with your medical team.

Can PGT-A improve my chances of pregnancy?

PGT-A can help select embryos that are more likely to implant, but it does not guarantee pregnancy. It may reduce the risk of miscarriage due to chromosomal abnormalities, but other factors also affect success.

Is PGT-A recommended for everyone?

No. PGT-A is often recommended for women over 35, those with recurrent miscarriage, or previous failed IVF cycles. However, it is not necessary for everyone. Your clinic can advise based on your medical history.

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.