Admittingly, it’s been a while since I’ve written here. My life has been filled with family, work, chaos, peace, and all the things life brings. I am grateful. I also want to occasionally run away screaming. But that’s normal, right? With two littles, and a husband starting up a new business, there’s never a dull moment. And I’m good with that (although I could use a few more ritual baths and date nights).
What caught my attention today is a new article from Embryoman. Side note: if you aren’t following him, you should be. He is a former embryologist who writes about the latest and greatest in infertility treatment technology from a scientific perspective. He has a knack for breaking down research papers, data, and outcomes with flair for everyone to understand. I appreciate his writing style and objective perspective. You can sign up for his free newsletter here, if you are so inclined, which is packed with accessible summaries of the most current infertility research. It really appeals to my research heart.
Back to the article in question. The headline read: No difference in euploid and mosaic embryo transfers! What’s that you say?! A recent study, that is pending publication, compares outcomes from transfers with euploid embryos (those are the “PSG normal” embryos you’ve heard so much about at the RE’s office and online support groups) versus mosaic embryos. Mosaic embryos are embryos where some of the biopsied cells come back “normal” and others are “abnormal” (meaning they have missing or duplicate chromosomes or parts of those). So there’s a mix of cells in the biopsy taken from the embryo, which leads doc’s to assume that the whole embryo is a mixed bag. Some mosaic embryos have a higher percentage of mosaicism, meaning that there are more abnormal cells present in the mix, and others have a lower percentage of mosaicism.
There’s been a lot of controversy surrounding mosaic embryos and PGS testing in and of itself. I must confess that I no longer have my finger on the current pulse of what common transfer practices are when it comes to PGS tested embryos. My most recent IVF baby is 2.5 years old (*gasp*) and I know how fast things change in the IVF world. When I was doing IVF, PGS testing was the norm, and, sadly, so was discarding PSG abnormal and mosaic embryos. I dove into every PSG-related article and study that I could find. I slowly came to the conclusion that PGS testing wasn’t right for me. I appreciated what PGS was trying to do, but I didn’t think that the science behind it adequately supported the treatment decisions that were being made. There was just too much they didn’t know. To ready more about my experience, the data I reviewed, and how I came to the decision that was right for me, check out this post. You can also read about how I ended up transferring an untested embryo and an abnormal embryo (*gasp again*) here and here, and the unexpected outcome of that transfer here.
Now back to that article. Embryoman explained that most of the studies that had been done previously looked at mosaic transfers after failed PGS normal transfers. The RE’s knew the PSG results of the embryos they were transferring, and when the mosaic’s failed, it was attributed to this flaw in chromosomes. But they were comparing PGS normal transfers (let’s call this group 1) versus mosaic transfers after already having a failed PGS normal transfer (group 2). I’ve always said that the devil is in the interpretation when it comes to study results. It’s simply incorrect to attribute the failed mosaic transfer in group 2 to mosaicism with this study design. An alternative explanation is that there is a 3rd factor causing both the normal and mosaic transfers to fail in group 2 (remember the women had failed transfers with normal embryos before participating in those studies). So there may be something else going on that causes these women in group 2 to not have a successful pregnancy regardless of the PGS results of the embryo transferred.
In this new study, the RE’s transferred PGS normal and mosaic embryos without knowing which were which. This is called a blind study and reduces bias. It also means that they weren’t just transferring mosaic embryos to women who already failed with PGS normal embryos. The playing field was leveled. And the results are a big deal.
They found that there was no difference between the PGS normal group versus mosaic group in miscarriage or pregnancy rates, live birth rates, or prenatal outcomes. And if your jaw hasn’t dropped yet, they also found no difference between the groups when they further compared embryos with low (20-30%) or moderate (30-50%) mosaicism with the PGS normals. And of the babies born from mosaic embryos, none had any mosaic related abnormalities. Yes, that is a big, big deal.
Why is it such a big deal? Because for quite some time, and maybe still in some clinics, mosaic embryos were not transferred for fear of having a miscarriage or baby born with a disability. It’s a big deal because I know there are women out there who were told they would not be allowed to transfer mosaic embryos. There are women out there who, due to earlier testing methods, were only told that their embryo was either normal or abnormal, with mosaic embryos considered abnormal and cast aside. There are women who reached the end of their finances, emotional rope, or whatever the line may have been, who did not get to transfer embryos that could have brought them that baby they wanted so very badly with all their hearts. And for those women, I hold space. My heart breaks for them.
For the women still in the trenches, I hope that this post gives you food for thought. Knowledge is power, and when it comes to infertility treatment we really do need to be our own best advocate. As I mentioned, I no longer know what is the most common practice in fertility clinics when it comes to PGS testing and transfers; and I know that in many medical fields, clinical practice tends to lag quite a bit behind scientific findings. But knowing that this research is currently being done gives me hope. Hope that clinics are keeping up to date on cutting edge research. Hope that they adjust their practices to be in line with new findings and recommendations. Hope that more women will have more chances with more embryos. Hope that you find you happy ending, whatever that may look like you for.