Pre-implantation genetic testing can be done for a variety of cases. You can have it if you have a specific genetic defect so either a structural rearrangement or something like cystic fibrosis and you can test your embryos to test for that genetic disease and you can then ensure if you have a embryo that is not affected with that disease or structural rearrangement you know that you can have a child, potentially have a child without that genetic defect and for those patients that need it, they should absolutely have it – a 100%. The other arm of preimplantation genetic testing is looking at aneuploidy within the embryo so that’s looking at the chromosomes. Making sure that you have 46 chromosomes and they’re all in the right shape. It’s currently red-lighted by the HFEA and some clinics will offer it and others won’t. Again, it should be applied not across the spectrum like it tends to be in other countries (America is quite heavy on the PGT-A front). My opinion is it should be applied for patients who specifically need it so, either recurrent miscarriage. I think something like 65% of miscarriages in the first six weeks are due to genetic abnormalities so if you have a recurrent miscarriage, then yes -you should be considering it. The other way that you might look at it is, if you don’t have that many embryos to choose from, the cost benefit ratio is wrong – it would just be cheaper for you to have an embryo transfer. If you have a lot of embryos to pick from, that’s when I might be tempted to use it – simply because you’re almost adding a cheat to the system. If you’ve got, for example, 10 blastocysts, you’re instead of having 10 transfers and the cost of 10 transfers, you could apply PGT-A see which ones are chromosomally normal and then you would be cheaper in the long run and also speed up your time to conception. So again, it could be used in that scenario but not across the board. Certainly again on patients specific based on their clinical history and how their embryos are in the lab.
In my personal opinion, based on experience, I would say you would need indications in the couple to apply this process. It is very valuable for women aged forty and above or who have a history of recurrent miscarriages during the first trimester, previous unemployed conception or pregnancy or repeated IVF attempts without a positive HCG. One of the main factors is that this is one of the areas we are testing the application of this type of process. In my opinion if we have indications in the patient it is a really valuable procedure. However, based on conferences and on opinions we have other countries that believe it is not worth doing and other countries that perform this in every kind and type of patient that comes to their clinic.
It is useful because you reduce the time to pregnancy, and you avoid unnecessary transfers. You avoid the stress of miscarriages. You avoid wasted months, mainly with advanced maternal age, so three or four months for a miscarriage or termination of pregnancy and then the psychological time to recovery. The psychological time to start again can be extremely detrimental for patients over the age of 37-38. So this is the first important advantage.
The second advantage is that you avoid doing clinical procedures that you know will not bring the success you are looking for from an ethical point of view. Whether these clinical procedures are undertaken in a private or public centre, reducing the money spent to generate an individual will benefit everybody.
As with any other technical procedures in medicine, PGS makes sense where there is a medical indication. That’s very important because it is an invasive procedure. We’re going to make a hole in the embryo, we’re going to take cells, and though most of the studies confirm that it’s a completely safe procedure for their health, whenever we may avoid manipulating the embryos, we should do it.
We currently recommend PGS when there is a higher risk of having genetic issues in the embryos. This is in cases where the patient is of advanced age, over 40, where there have been recurrent miscarriages, where there is some kind of genetic abnormalities. Either because the karyotype is abnormal or there is a severe male factor, which has also been related to a higher risk of having problems with the sperm.
In all those cases, it may make sense because we’re going to discard a lot of embryos. If you are doing, let’s say, a double donation, so you’re using donor sperm and an egg donor, PGS does not make any sense because most of the embryos are going to genetically normal.
