What is PGTA?
Pre-implantation genetic testing for aneuploidies or PGT-A, is a genetic test performed on embryos created during an IVF cycle. With PGT-A it is possible to obtain information about the genetic content of early embryos. PGT-A is a selection tool used to increase the likelihood of a healthy on-going pregnancy but unfortunately it does not guarantee it.
PGT-A is the procedure whereby a small number of cells are removed from the embryo and tested to determine the presence or absence of chromosomes, with the aim of avoiding the transfer of embryos with an incorrect number of chromosomes. PGT-A may reveal that some or all your embryos are abnormal and these embryos would not be used.
Can PGTA increase my chances of having a baby?
PGTA will not increase your overall chances of having a baby. It may however reduce the number of unsuccessful cycles you undergo and reduce the time taken to acheive a pregnancy. This is because it ensures that only chromosomally normal (euploid) embryos are transferred.
The chances of pregnancy and live birth are higher if a euploid embryo is available and transferred. The graph below shows how this difference increases with the age of the woman.
What are the risks of PGTA?
PGTA is a well established technique. However, as with all techniques there are some risks to consider
Small chance of damage to the embryo during biopsy procedure
Small chance of not getting a result from the biopsy (5%)
Small chance of getting an incorrect result or misdiagnosis (3%)
Not having suitable embryos to biopsy
Not having any normal (euploid) embryos to transfer
Small chance of embryo not surviving the freezing and thawing process
Why are my embryos frozen?
Once cells from the embryo have been sampled (embryo biopsy) these need to be tested. This testing takes time (2-4 weeks), therefore, the embryos need to be frozen whilst the results are awaited. Once we have the results we can arrange a frozen embryo transfer (FET).
Will PGTA reduce my risks of miscarriage?
PGTA can reduce the chance of miscarriage associated with chromosomal abnormalities. Although there are many causes of miscarriage, chromosomal abnormalities are the most common cause.
Miscarriages associated with chromosomal abnormalities become more common with age. The graph below shows the difference in miscarriage rates at given ages in cycles where PGTA has been undertaken compared to conventional treatment.
Who can benefit most from PGTA?
Older women (over 38)
Patients with recurrent symptoms implantation failure
Patients with recurrent miscarriage
I am 34 can I benefit from PGTA?
Although older patients (>38) are more likely to produce more chromosomally abnormal embryos, patients of all ages will have a proportion of embryos which are not normal. Conventional treatment involves selecting embryos on the basis of their appearence (morphology or grade) and this does not always mean that the embryo is chromosomally normal. A recent study of women under 35 suggested a significant increase in the chance of a live birth in a first attempt at IVF when PGTA was used.
Does PGTA increase the cost of my treatment?
PGTA is an 'add on' and does have an additional cost. The cost depends on how many embryos you have to biopsy. Your clinic will discuss the individual costs with you.
When comparing to conventional treatment where all good quality embryos are used or stored for future use, PGTA can be cost effective reducing the number of frozen embryo transfers you undergo and the costs associated with these. Thus PGTA can be a cost effective intrevention.
What are the chances of having a chromosomally normal embryo?
The table below shows the chance of having at least one normal (euploid) embryo at a given age depending on how many embryos are available.
For example at age 38 if two embryos are available there is a 48% chance of getting at least one normal embryo and this will increase to 94% if nine embryos are available.
Transfer of a normal embryo does not guarentee it will implant but the chances are higher.
Can I do PGTA on embryos I have previously frozen?
Embryos that have been previously frozen can be thawed, biopsied and refrozen in order to do PGTA. This may be useful if you have a number of embryos in storage and want to limit the number of transfers you undertake. However, the chances of success are slightly less than when PGTA is undertaken in a fresh treatment cycle.
Are there any other benefits of having PGTA?
PGTA can help reduce the burden of IVF treatment. Although it will not increase your chance of having a baby, it may reduce the time to pregnancy, the number of transfers you undergo and reduce the risk of miscarriage or chromosomal abnormalities in a baby.
Where is PGTA available in Northern Ireland?
The NHS does not currently provide PGTA. Belfast Fertility is the first clinic in Northern Ireland to receive a PGTA license from the HFEA and is currently the only authorized clinic to conduct this procedure. A patient information leaflet from Cooper Surgical who provide our genetic testing can be downloaded below or see further information on their website.
Helpful patient information on PGTA can be found on the HFEA website here
If you have further questions or want to discuss whether PGTA may be of benefit to your treatment make an appointment.
Comments