There are people in this world such as fertility specialists on CHR (Center for Human Reproduction in New York) who are true magicians in making women pregnant and who really understand the issues surrounding low ovarian reserve or bad egg quality in women over forty.
So when they say that the PGS (pre-genetic screening, also called PGD or pre-genetic diagnostic) is ineffective and basically a waste of time and money for most women who test their embryos this way, I take that very seriously.
Here is why many leading fertility specialists are seriously questioning the usefulness of PGS and what you need to know about it so that you can make a better choice for yourself.
How is PGS done?
PGS is a procedure designed to examine your embryos for chromosomal abnormalities. An embryo biopsy (a small piece of an embryo, usually just a few cells) is taken at the blastocyst stage at day five, and all chromosomes are examined.
Sounds perfect, right? I mean,who would not want to make sure that only healthy embryos are transferred?
But this is where Mother Nature comes into play and tells us we still have a lot to learn.
The thing is, embryos appear to be MUCH more robust and smart than we give them credit for. From the first cell on, embryos seem to have an amazing ability to self-correct – something we just started to understand in recent years.
This means, for example,that one abnormal cell that was created during early embryonic divisions will often become naturally “sorted out” and “pushed away” from the embryonic mass to create a layer which will later become the placenta and NOT become part of your baby. We call such embryos”mosaic”, meaning composed of several cell lineages, and it turns out that approximately 50% of all embryos in women in over fortycould be made this way.
Unfortunately, this irrelevant outside cell layer (also called trophoblast) is the part from which cells are taken for PGS screening, meaning that, if it turns out that the number of chromosomes is not right there, doctors will advise against transferring that embryo. Even worse, it will become discarded for the reason that we did not recognize their ability to self-correct.
Is PGS worth it?
Am I now advising against the PGS? For sure not. I’m only saying that some serious people who are serious about understanding fertility at the advanced age doubt that this technique is adequate for most of their patients.
This means, if you are young and have plenty of beautiful, healthy eggs and embryos, you can test them all with PGS and finally take only the very best ones. But if you have only a few eggs and embryos during an IVF, it comes close to a tragedy if you pay for this expensive procedure, to then discard embryos which would have given a healthy baby if only they got a chance to implant.
Lately I’ve had several questions in my consulting sessions (here you can read how to find me when you have a question) from women who actually banked embryos one by one over the course of one year or even longer…to then find out after a PGS that NONE of the embryos was perfect.
How devastating is that?
These women would have probably made a better decision by transferring embryos in each IVF instead of banking them one by one on ice.
Unviable embryos would have most probably ended up as early miscarriages, and the viable ones would have gotten their chance to live and develop. These are, of course, difficult issues and very hard decisions to make, particularly in women over forty who, anyway, have an increased risk of all kinds of pregnancy complications. Still, when talking to these women, I get the impression that any strategy would have been psychologically less devastating than just waiting, banking embryos, performing PGS, and then starting all over again.
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