First of all, I must say that I would advise all couples that come for IVF to do karyotype because sometimes unexpectedly we can find some information about balanced chromosomal rearrangements in the couple. Some people have this chromosomal rearrangement, they carry them, and they don’t know it before they start the IVF. It happens quite often, and it is one of the important reason for failure in pregnancy, having chromosomal rearrangements. I would advise doing karyotype if you have any problem with having a pregnancy. So, you can exclude if there are some mistakes.
It is so important because if you have some mistakes in a chromosomal organization, you could have an embryo, which will look perfect just because during the first division, the cells would use the potential of their mother cells, and they would divide properly. They would organize improper blastocysts, and they would have the perfect potential for implementation and then if there were some mistakes in chromosomal rearrangements in their parents, they could have some small mistakes of the genome. In this kind of defects, they would have developed babies with some diseases, and it is even worst than not having children, and that’s why karyotyping is really important, and you should start with it if you just want to start the IVF cycle.
Another thing is that some people have a little bit higher rate of chromosomal mistakes in embryos and again it depends on genetics and unfortunately, it is really hard to find using usual methods. Sometimes, some genes that help cells to separate chromosome properly or some other types of cellular proteins which work usually normally in our bodies but if we are talking about oocytes for example which as I said are quite old cells. In this case, these mistakes begin to be a little bit more important, so for normal cells which divide really fast and it’s just mitotic division, some insufficiency of some proteins don’t have to be so important, so it doesn’t hurt them, but for oocytes because of the ageing, it becomes a bigger problem, so in those people, the rate of the embryos with chromosomal mistakes could be a little be high.
If you already have some experience with miscarriages, you need to have all the information about this pregnancy, from karyotyping these embryos just to understand the reason. If it is repeated, chromosomal rearrangement mistakes even if it wouldn’t be the same chromosome, it could be different chromosome, it can be a kind of prediction that it is better to do PGT-A to select the euploid oocytes before transfer.