When I started out on my journey for baby 2.0, I was pro-PGS testing. Completely on the PGS bandwagon. It sounded like a dream technology – something that will eliminate the concern for having a baby with a serious health problem, drastically reduce the risk of miscarriage or still birth, and increase my chance of pregnancy. And at age 40, that sounded too good to be true. But what if it is too good to be true?
After having a PGS normal embryo fail to implant at my first FET, I was shocked and devastated. After 3 subsequent rounds of IVF, 2 that resulted in no embryos even making it to blast for testing and the other ending in 2 PGS abnormal embryos, I began to seriously question the approach. The more I read about PGS testing, the more I carefully climbed down off of the PGS bandwagon. I started to read that although PGS is often recommended for older women, these older women, as well as women with diminished ovarian reserve (DOR), are the very women that may benefit least from PGS. In fact, it may actually lower IVF success rates!
There are several factors involved here. First, if you struggle to make blasts you may not even have anything to test on day 5. That means no transfer, which equals a zero percent chance of pregnancy. You might as well have saved yourself a bunch of money, shots, and ultrasounds and just had sex instead. At least that would give you some chance of pregnancy.
Second, more and more studies are coming out that call into question the accuracy of PGS test results. At my RE consult today, my RE pulled out a medical journal to show me a research study that was published just a few days ago where they transferred mosaic embryos. A lot of them. This was done in Italy. I didn’t have time to read all the details but the study found that all the mosaic embryos transferred made healthy, normal babies. In conclusion, the authors suggested that we should be transferring mosaic embryos and warned of how many babies are essentially being “thrown out”. This gets complicated because mosaicism isn’t necessarily an all or nothing thing – it comes in percentages – and some labs don’t even differentiate and instead call all mosaic embryos “abnormal”. But it doesn’t stop with mosaic embryos. Last year my own RE told me about a study he did where they biopsied embryos at day 5, but also immediately transferred one of the biopsied embryos during the fresh IVF cycle. That means they got the PGS results after the embryo was already transferred. One of the results came back abnormal (not mosaic) – it was an abnormality that was supposed to be incompatible with life. My RE and the staff all waited for this poor women to miscarry, and to their complete shock she did not. That baby is now a healthy bundle of joy. And there are lots of stories like this.
Furthermore, when you biopsy for PGS you are taking cells from the trophectoderm (TE), which becomes the placenta. Studies are showing a) that the TE contains more abnormal cells than the inner cell mass (ICM) that becomes the baby, b) that abnormal cells may even be pushed out into the TE to keep them out of the ICM, and c) that they may self-correct down the line after the blast stage. So when you are only biopsying the TE are you really able to make an accurate assessment of the baby? Maybe not.
One point that I found interesting in the articles I read explained that mathematical models demonstrate that when you only have 5 or 6 TE cells (a typical PGS biopsy) the rates of false negatives (saying an embryo is normal when it’s not) and false positives (saying an embryo is abnormal when it’s not) is simply too high to accurately determine whether those cells accurately reflect the ICM. Let me say that again – math says you just don’t have enough data to make a reliable determination.
I could go on, but I’m just going to link to some articles so you can do your own reading, if you care to. That being said, I do think PGS has its place. If I made lots of blasts it could be a useful tool for helping my RE select which embryo to transfer. After all, when you have lots of blasts and several PGS normal embryos, the error isn’t as harmful. I can also see why women who have had several miscarriages would opt for PGS testing in an effort to improve the odds. But that’s not me either and I don’t have many embryos to work with.
For more reading on PGS, check out this study, this one, here’s another, and one last one. I wish I had a link for the Italian study my RE showed me today, but I don’t have electronic access to that medical journal. Ultimately it’s a hard and personal decision. Given my history, I’m not going to do PGS testing next time.