PGT-A TESTING
PGT-A screens embryos for genetic health, helping us select those with the best potential for a successful pregnancy.
What is PGT-A?
The first cell of an embryo is made up of a set of chromosomes from the sperm and another set from the egg. If the cell doesn’t have the right number of chromosomes, this can lead to implantation failure or miscarriage. PGT-A allows us to analyse the cells from an embryo to check for the correct number of chromosomes before they’re transferred to the womb.
By using PGT-A, our embryologists have up to a 98% chance of identifying embryos with abnormalities before transfer. Embryo selection can help improve IVF success rates and reduce both the chance of multiple pregnancies and the likelihood of miscarriage.
Who is PGT-A for?
PGT-A is suitable for all patients, but in particular:
- People who want to achieve a quicker route to pregnancy
- Patients who have experienced recurrent miscarriages of unknown cause or anyone who has been through previous unsuccessful IVF treatment
- A high number of people who have been in the position where they feel that their only option is to give up and then have PGT-A, in many cases they manage to have a baby
Additionally, PGT-A can be of benefit when:
- Where the female partner is 36 years of age or older
- Patients who have had a previous child or pregnancy diagnosed with a chromosome abnormality
- Patients who produce many embryos and want to ensure transfer of an embryo of known chromosome status to optimise chances of success (we know that up to 50% of embryos in any one cycle may be chromosomally abnormal)
The benefits of PGT-A
PGT-A testing can help identify the embryos with the most potential to result in a successful pregnancy. PGT-A testing can’t change the number of viable embryos available for transfer but, by transferring only those that have the correct number of chromosomes, the time taken to establish a pregnancy can be shorter and the distress of failed IVF treatment and risks of miscarriage can be reduced.
Where patients have undergone multiple rounds of IVF and have no explanation for the treatment failure, PGT-A testing can sometimes provide answers and help with decisions about future treatment options.
Care Fertility's own data shows that by performing PGT-A and transferring euploid embryos clinical pregnancy rates (CPR) are increased. In the year to 31 July 2023 Clinical Pregnancy Rate per embryo transferred across patients of all ages following PGT-A was 55%(1), compared with 36%(2) in non PGT-A cycles.
(1) Based on 919 euploid embryos transferred resulting in 501 pregnancies with a fetal heartbeat.
(2) Based on 5388 embryos transferred (without PGT-A) resulting in 1916 pregnancies with fetal heartbeat.
A clear and straightforward pricing approach which makes PGT-A more cost effective.
Time lapse imaging with Caremaps-AI is included.
Specially trained doctors and genetic counsellors to provide you with specialist PGT-A advice
Virology Screening is required of all our patients who are planning on using their own sperm in their fertility treatment. This important first step is where we check for viral infections, such as Hepatitis B, Hepatitis C and HIV, which you may not be aware you have but could impact your fertility and your treatment. Knowing if you have any of these viral infections will allow us to advise you on what steps, if any, need to be taken before starting treatment.
The virology screening is a relatively quick and painless step at the start of the fertility treatment process. We check for viral infections by taking a small blood sample for testing.
The PGT-A process
Embryos are produced through an IVF cycle
We are very experienced in freezing and thawing of embryos, we use a process called ‘vitrification’. Vitrification involves much more rapid cooling than other less advanced methods of freezing, and it prevents ice crystals from forming. This preserves the quality of the cells and improves the chances of success when they are thawed. Vitrification has greatly improved the success of embryo freezing and it’s now a very reliable practice.
Testing is carried out using cutting-edge technology to analyse the number of chromosomes present within the embryo's cells.
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 four results:
This means the embryo is genetically balanced with 46 chromosomes. These embryos can be transferred.
Some embryos may have both chromosomally normal and abnormal cells or a mixture of the two – they are known as mosaic embryos.
In fewer than 5% of cases, we simply won’t be able to tell whether the embryo is euploid or aneuploid. These can still be transferred or, in special circumstances, they might be re-biopsied.
What are the risks of PGT-A and blastocyst biopsy?
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.
PGT-A testing may result in a false positive or false negative
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.
Fewer embryos available for transfer
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.
Risks of mosaicism
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.