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PGT-A TESTING
Preimplantation Genetic Testing for Aneuploidy screens embryos for genetic health, helping us select those with the best potential for a successful pregnancy.
What is Preimplantation Genetic Testing for Aneuploidy (PGT-A)?
Preimplantation Genetic Testing for Aneuploidy (PGT-A) is an advanced genetic test that helps us identify embryos with the correct number of chromosomes before transfer. By selecting embryos with the right chromosome balance, we can support your chances of implantation, reduce the risk of miscarriage, and help you move towards a healthy pregnancy.
At Care Fertility, PGT-A is performed at the blastocyst stage, when embryos have developed for around five to six days. As part of the process, we also assess how the embryo was fertilised at a very early stage, known as pronuclear (PN) status. This gives us an additional layer of insight into embryo development.
Why the number of chromosomes matters
The very first cell of an embryo contains one set of chromosomes from the egg and one set from the sperm. For development to progress normally, that cell needs the correct number — 46 chromosomes in total.
If an embryo has too many or too few chromosomes (a condition known as aneuploidy), it may not implant, or it may result in miscarriage. This is one of the most common reasons IVF cycles don’t lead to pregnancy.
The challenge is that even embryos that look healthy under the microscope can still carry chromosomal abnormalities. In other words, appearance alone doesn’t always tell the full story — even for experienced embryologists.
How PGT-A helps with embryo selection
PGT-A allows us to analyse a small number of cells taken from the outer layer of the embryo. We then assess whether the embryo has the correct number of chromosomes before it’s transferred to the womb.
Using PGT-A, our embryology team can identify embryos with chromosomal abnormalities with up to 98% accuracy. This information helps guide embryo selection in a more informed way — particularly when:
- Several embryos are available
- There is a higher risk of chromosomal abnormalities
- There has been previous implantation failure or miscarriage
By transferring an embryo with a normal chromosome result, we may improve the chance of success per transfer. It can also help reduce the likelihood of miscarriage linked to chromosome differences, and support single embryo transfer — lowering the risk of multiple pregnancy.
How is genetic testing done?
PGT-A is performed on blastocyst embryos. This may include embryos that have both typical and atypical fertilisation patterns. As embryos develop, embryologists may also note early fertilisation patterns, including the number of pronuclei present.
Embryos are biopsied, during which an embryologist removes around five cells from 30+ cells on the outer layer of the embryo – this is called the ‘trophoblast’. These cells would normally contribute to the placenta, so this process does not affect the developing foetus.
Studies have shown that removing a few cells from the blastocyst does not harm embryo development, and thousands of babies have been born following PGT-A.
PGT-A results
Usually our embryologists choose embryos for transfer based on the way they look and develop. This certainly does work, but PGT-A lets us go deeper, allowing us to analyse the genetic makeup of embryos and check that they have the right number of chromosomes before they’re transferred to the womb. By using PGT-A our embryologists can single out embryos with abnormalities before transfer.
With PGT-A, each embryo will have one of three results:
Benefits of PGT-A
PGT-A gives us greater clarity at one of the most important stages of IVF — embryo selection. By analysing a small number of cells from the outer layer of the embryo, we can assess whether it has the correct number of chromosomes before transfer. Using this technology, our embryology team can identify embryos with chromosomal abnormalities with up to 98% accuracy.
That level of insight means we’re not relying on appearance alone. Instead, we can make more informed decisions about which embryo has the best chance of leading to a healthy pregnancy. For many patients, this can mean fewer failed transfers, reduced uncertainty, and a clearer path forward.
PGT-A helps identify embryos with the most potential to result in a successful pregnancy. While it can’t increase the number of viable embryos available, it can help us prioritise those with the correct number of chromosomes for transfer.
Because chromosomal abnormalities are one of the most common causes of miscarriage, transferring an embryo with a normal chromosome result may reduce this risk. For some patients, this can also shorten the time it takes to establish a pregnancy and help avoid the emotional strain of repeated failed cycles.
If you’ve been through multiple IVF cycles without a clear explanation for treatment failure, it can feel frustrating and confusing. In some cases, PGT-A testing can provide answers.
Understanding whether embryos are chromosomally normal can help guide future treatment decisions. It may clarify whether to continue with your own eggs, consider alternative options, or adjust your approach. Having this information can make next steps feel more informed and less uncertain.
At Care Fertility, our data shows that PGT-A increases clinical pregnancy rates (CPR) to 56% per embryo transfer, compared to 39% in non-PGT-A cycles (August 2024 – August 2025 data).
While no treatment can guarantee success, selecting an embryo with a confirmed normal chromosome result can improve the chance of pregnancy per transfer. For many patients, that means a more efficient treatment journey.
Time-lapse imaging with Caremaps Ai is included as part of your PGT-A cycle.
This technology continuously monitors embryo development inside the incubator, without disturbing their environment. It provides additional insight into how embryos are developing, supporting informed embryo selection alongside genetic testing.
PGT-A can raise important questions, and we believe you should feel fully informed before making any decisions.
Our specially trained fertility doctors and genetic counsellors are here to provide personalised advice and guidance. They’ll talk you through what the results mean, explain any implications, and support you in deciding what feels right for you.
As part of PGT-A at Care Fertility, we also assess pronuclear (PN) status — an early indicator of how an embryo was fertilised.
Typically, a normally fertilised embryo shows two pronuclei (2PN) — one from the egg and one from the sperm. Historically, embryos showing one pronucleus (1PN), 2.1PN, or three pronuclei (3PN) were considered abnormally fertilised and were often discarded.
We now refer to these as atypically fertilised embryos.
Research has shown that some atypically fertilised embryos can go on to develop into healthy blastocysts and may be genetically normal (diploid and euploid). Others may be haploid (one set of chromosomes), triploid (three sets), or polyploid (multiple sets).
By combining PGT-A with PN assessment, we are able to test these embryos rather than automatically discarding them. This means that embryos previously thought to have no potential can now be carefully analysed and, in some cases, considered for transfer if they are found to be chromosomally normal.
For some patients, this may increase the number of embryos available for consideration and provide additional opportunities within a treatment cycle.
Who is PGT-A for?
PGT-A can help identify embryos with the correct number of chromosomes before transfer. By focusing on embryos that are more likely to implant, some patients may reach pregnancy in fewer transfers. For many, that can mean a shorter, more focused route through treatment.
If you’ve had repeated miscarriages without a clear cause, it can feel confusing and exhausting. In some cases, miscarriage happens because an embryo has the wrong number of chromosomes. PGT-A can help us understand which embryos are chromosomally normal before transfer, which may reduce the risk of miscarriage linked to chromosome differences.
If previous IVF treatment hasn’t resulted in pregnancy, it’s natural to question what went wrong. Sometimes, embryos look good in the lab but carry chromosome abnormalities that prevent implantation or lead to early loss. PGT-A gives us more information about embryo chromosome status, which can help guide next steps and, for some patients, change the outcome of future cycles.
We often meet people who feel they’re at the end of the road. In some cases, PGT-A provides new insight into embryo quality that wasn’t visible before. While it’s not the right option for everyone, it can offer renewed direction for those who’ve been told there’s little else to try.
As we get older, the proportion of embryos with chromosome abnormalities increases. By the mid-to-late thirties, this becomes more common. PGT-A can help identify embryos with the correct chromosome number, which may improve the chance of implantation and reduce the risk of miscarriage in this age group.
PGT-A pricing
We know costs are an important part of planning treatment. PGT-A pricing is split into a one-off set-up fee and a per-embryo testing fee, depending on how many embryos reach biopsy stage. The details below explain how each fee works and what’s included.
PGT-A set-up fee
What this covers
This is a one-off fee for your treatment cycle and includes:
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Treatment set-up
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Embryo biopsy set-up
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Caremaps Ai embryo assessment
This fee applies regardless of how many embryos are biopsied.
What’s not included
Extended culture and ICSI (if required) are not included in this fee.
PGT-A fee per embryo
What this covers
This fee applies to each embryo that is biopsied and sent for PGT-A testing. Only embryos that reach biopsy stage are included, so the final cost depends on how many embryos are suitable in your cycle.
How this fee works
The per-embryo fee is added to the one-off PGT-A set-up fee. Your Care Fertility team will explain how many embryos are recommended for testing and talk you through costs before treatment moves forward.
PGT-A risks and HFEA guidance
The independent regulator of fertility treatment, the Human Fertilisation and Embryology Authority (HFEA), has developed a new rating system and provides information about treatments that are offered on top of your routine fertility treatment – known as treatment add-ons. Their add-on ratings are based on published evidence, which the HFEA deems to be of suitable quality and quantity.
For each add-on, ratings are provided for treatment outcomes, and for patient populations, for which this evidence was available at the time.
- The HFEA has given PGT-A several ratings because they consider it to be beneficial for specific patient types, and not for all patients
- For miscarriage reduction overall, PGT-A has been rated green, meaning that there is high quality evidence demonstrating its effectiveness.
- For improving live birth rate for most women, the rating is red, indicating that this add-on may reduce treatment effectiveness for some patients. Other outcomes measures have been rated grey which indicates there is insufficient evidence to confirm either way
We believe it is important that you have all the information you need before you decide to have treatment using PGT-A. We also recommend that you read the information on the HFEA website regarding add-ons and how the ratings were decided, before making a decision.
Although testing is generally very accurate, PGT-A testing may result in a false positive or false negative result in around 3% of cases. In the case of a false positive result, an embryo that may have implanted and developed may be discarded. In the case of a false negative result, an embryo with more or fewer than 46 chromosomes may be transferred.
It is very likely that following PGT-A testing there will be fewer embryos available for transfer or future use as we do not transfer any embryos with an incorrect number of chromosomes - these embryos would not have developed into a successful pregnancy.
Sometimes, the PGT-A result is reported as mosaic, which means the embryo is likely to contain both euploid and aneuploid cells. The proportion of euploid and aneuploid cells can impact the chance of successful outcome if the embryo is transferred. Mosaic embryos may have a lower chance of pregnancy but there are reports of healthy births after a transfer of a mosaic embryo. We will support you with your decision making if mosaicism impacts your treatment.