Well, no. I want to be very clear, in our clinic we personalize each case, it’s crucial to be aware, that the PGT-A is a very effective tool, but for those who will benefit from it.
We have two types of patients, low-risk patients and high-risk patients. The patients who are called high-risk, are the ones who have chromosomal abnormalities in the karyotype, or they have some monogenic disease. It is mandatory to perform the PGT-A for people who have a chromosomic problem. We have to do the PGT-A to try to increase the pregnancy rates and decrease the miscarriage rate without any doubt.
On the other hand, we have high-risk patients who f.e. have recurrent implantation loss, implantation failure, older women or male with severe factor. In that case, it’s controversial to use PGT-A.
There are pros and cons to this. In our clinic, we think that it’s a well-known fact that PGT-A decreases the risk of miscarriage and improves implantation rates. Imagine that we have an older woman with polycystic ovaries, she will have a lot of embryos. And yet because of her age, she will have a lot of abnormal embryos, we can perform the PGT-A to decrease the time or the treatments until a pregnancy.
If we have ten embryos and then we know that probably because of her age, we’ll have three or four normal embryos. We can do the PGT-A to try to decrease the time until her pregnancy, and also it will decrease the twin pregnancy rate or multiple pregnancies. Because in that case, we’ll transfer more than one embryo to get one pregnancy. So that is why it is better to do the PGT, in that case. It’s important to say that PGT-A is still a developing technique. We need to have a very good laboratory because the lab needs to guarantee a good culture to blastocyst, it needs to guarantee an efficient vitrification technique, and also that the embryo will not be damaged after the biopsy. So indefinitely, the patients will need to rely on the embryologist skills, and sometimes some clinics don’t have these conditions.
Another thing is that sometimes we don’t have any embryos to be biopsied. F.e. women who have a low ovarian reserve, we don’t have any embryos to be biopsied, this can increase their anxiety and also increase the cancellation rates.
Women with very poor egg quality, f.e. women who have endometriosis which affects the oocytes, that will mean the embryos also will be of poor quality. So sometimes they might not even reach the blastocyst stage. So in that case, in our clinic, we need to think of what want, an opportunity or security. At times, these patients with low ovarian reserve or with endometriosis will benefit more with an embryo day-3 transfer. If we did a biopsy on an embryo coming from an older woman with endometriosis, we would probably kill the embryo, even if it is euploid. In this case, we cannot assure the patients that after the biopsy, the embryo will survive. We need to guarantee it, we need to allow them to have a transfer, and sometimes the transfer is done on a day-3 or even a day-5 without any biopsy.
The last thing is that to do the biopsy, we need to take a sample of 5 to 10 cells, and these cells they come from the trophectoderm, and we can find a false positive. It means that the cells that come from trophectoderm do not correlate very well with the inner cell mass. If the lab informs us, that this is an abnormal embryo and it is not true, it is a false positive. It is connected with mosaics. A mosaic embryo has normal cells and abnormal cells. It has been proved, that at least 20% of the embryos from a cycle are mosaics. These mosaics have slightly less implantation rate and clinical pregnancy rate than a euploid embryo. It means that this embryo can lead to a healthy baby. If we do the PGT, this embryo in some clinics, they will be ruled out, depending on the level of the mosaicism, whether it is a low-risk mosaic or high-risk mosaic. It depends on the location of the abnormality, the percentage of chromosomes affected. There is this type of disadvantage, which are the mosaic embryos, so PGT-A is a useful diagnostic tool, but we need to focus on personalizing the treatment, and we need to choose it but not for all patients.