The Lie of the Perfect Embryo: Why Euploid Doesn’t Mean Guaranteed

You were told your embryo was “perfect.”
 It was euploid. Genetically normal. The best one.

So why didn’t it work?

In this episode, Dr. Mark Amols breaks down the truth behind PGT testing and explains why even genetically normal embryos can fail to implant or result in miscarriage.

You’ll learn:

• What PGT-A actually tests (and what it doesn’t)
• The difference between chromosomal abnormalities and single gene disorders
• Why microdeletions and tiny DNA changes can go undetected
• How embryo biopsy sampling works (and its limitations)
• Why implantation depends on more than just DNA
• The real theoretical ceiling of IVF success—even with “perfect” genetics

PGT is powerful. It reduces miscarriage. It improves efficiency. But it is a filter—not a crystal ball.

If you’ve experienced a failed euploid transfer, this episode will help you understand why that doesn’t mean your embryos are bad, your clinic failed, or IVF won’t work.

There is no such thing as a perfect embryo. There are only probabilities.

Thanks for tuning in to another episode of 'Taco Bout Fertility Tuesday' with Dr. Mark Amols. If you found this episode insightful, please share it with friends and family who might benefit from our discussion. Remember, your feedback is invaluable to us – leave us a review on Apple Podcasts, Spotify, or your preferred listening platform.

Stay connected with us for updates and fertility tips – follow us on Facebook. For more resources and information, visit our website at www.NewDirectionFertility.com.

Have a question or a topic you'd like us to cover? We'd love to hear from you! Reach out to us at TBFT@NewDirectionFertility.com.

Join us next Tuesday for more discussions on fertility, where we blend medical expertise with a touch of humor to make complex topics accessible and engaging. Until then, keep the conversation going and remember: understanding your fertility is a journey we're on together.

Transcript

0:00

Today we talk about exposing the lie of the Perfect Embryo. I'm Dr. Marc Amols, and this is Taco about Fertility Tuesday. In today's episode, I want to talk about something that confuses and frustrates all lot of patients. You go through ivf, you do genetic testing, and you're told the embryo is euploid, normal, perfect. And then it doesn't work. No pregnancy, or maybe even a miscarriage. And suddenly you start to think, what happened? I thought this one was perfect. So today's episode is called, the Lie of the Perfect Embryo. Because perfect is not really what PGT means. So let's start with what PGT really does. PGT A looks at chromosomes. Think of it. Big picture genetics. It checks. Do you have all 46 chromosomes? Are any missing, duplicated, or large chunks gone? That's it. It's powerful, it's useful, it improves outcomes, but it's low resolution. Let me give you an example. The emeru may be called Euploid because when they look at it, they can see all these chunks missing or additions, but only to a certain point, about 10 megabits and below that, they really can't see it. So think of it like you see a guy coming up from about, let's say 100ft away. I ask you, hey, does that guy look normal? And you look at him, you go, yeah, he's got two arms, two legs, seems to be walking fine. He looks normal. And then he gets up to you and I say, no, he's not. And then you notice he's missing multiple fingers, he's missing part of his ear. And you didn't even realize that he's actually blind in one eye, that you realize he doesn't have an eye in that eye. M. Now, it's not that you were wrong before. You were absolutely correct, but it was a hundred feet away. The resolution was not that good. When he got closer, you can now notice these little things like deletions or additions. That is PGT in a nutshell. It's the 100 foot away view of genetics. And what that means is it's going to miss some of the small things, which is why the embryo is not perfect. This is why things like cystic fibrosis or SMA or Huntington's disease needs PGTM M, not PGT A. Because PGTM M uses primers to look for specific genes. Completely different tests for a different purpose. PGT A cannot find those small issues. There are also very small missing, duplicated DNA segments that are usually 5 or under 10 million base pairs. And although that sounds huge in genetics, that's actually very tiny. So some of these deletions are very important genes. And yes, they will cause things like failed implantation, miscarriage, even developmental problems. And, the thing is, most PJT platforms will not see them reliably. This is one of the reasons that you can have a euploid embryo, which we think is perfect, and yet it doesn't work. The testing wasn't wrong. What it showed looked perfect, but it doesn't have the resolution to know for sure. There's also other issues, such as sampling error and mosaicism. When we biopsy an embryo, it's only a few cells. We're not actually testing the whole embryo. So sometimes the tested cells are normal and other cells are not. That's what we call mosaicism. Since we're sampling the embryo and not cloning it. Even our low resolution evaluation of the genetics is not going to be perfect. The real big question is, does it matter when these small deletions occur? And the answer is yes, but, not often. See, if microdeletions were that common, PGT wouldn't work. So we know when PGT says the embryo is euploid, most of the time it is correct. But it's not always. We know that PGT is going to reduce miscarriages. We know that it's going to improve the pert transfer success rate. But there are a few percent of embryos that are called euploid and technically are not perfect. The good news is even those the small little errors might be real, they're usually not the main problem. The main problem is going to be the big chromosomal errors, such as the guy missing an arm or missing a leg, missing a finger. You can still pretty much do everything, such as washing a cup, making food. You just can't do gang signs anymore because you're missing some fingers. So then, if the embryo could be found perfect, let's say we were able to come up with a PGT A that always 100% was correct, that the embryo was genetically normal and that it was the perfect embryo, then we would assume that every transfer would work. And the answer is no, it won't. Because genetics is only one piece of the puzzle. DNA is a very important part. Having normal chromosomes is a huge portion. But there are other issues that can develop, such as bad metabolism or weak mitochondria, or even poor gene expression. It's like having the perfect blueprint. But sometimes the execution of the blueprint doesn't always work. I deal with this all the time where I let's say building clinic and we have a blueprint and then they mess up. And not because the blueprint was wrong, which is equivalent to the DNA, but because someone misread something and something went wrong. Well, the same thing happens in life. Matter of fact, it happens so much that we actually have repair mechanisms constantly going around fixing all of the mistakes. And sometimes those mistakes are so large they can't be fixed. But even beyond genetics, there's things like the uterus. It really matters. The timing matters, the hormones matter. Even things like inflammation or scarring, where even pumps in the uterus, can all affect your chances. Blood flow is another big one. If you had an ablation of your uterus and you don't have good blood flow to your lining because you burnt all that lining, there's a good chance it may not work. You can literally have the best embryo in the world and it may not work because the soil is not good anymore. So you can put the perfect seed in, but if the ground is bad, it can't grow. But even if all of that was perfect, there's still the uncomfortable truth, which is biology is inefficient. Humans are not perfect, especially when it comes to reproducing. And this is the way it's always been. Even naturally. Not every embryo is going to implant. Not every embryo is going to make it to live birth. Not every sperm is going to make it to the egg. The only difference with IVF is now it's visible. We can actually see these things happening, and so we know what's specifically happening that's going wrong. Whereas naturally you just assume, oh, well, the egg didn't fertilize, when in reality it may have fertilized and the embryo just never implanted. But you don't know that because there's no way to see inside your uterus. The point here is that there is a theoretical maximum success level. If PGT were perfect, what would that success be? Well, if we could see every mutation, every error, it still would only be about 70, 80% live birth rate, not 100%. And that's because implantation is biology. It's not just DNA. And so those other things like cell signaling, blood flow, immune systems, and some of the things we talked about before are all going to affect it. I don't believe we will ever get to 100%. And most professionals believe probably 70, 80% is going to be the maximum that we'll ever get to. So in the end, what does this all mean if you had a failed embryo transfer, well, it means it's not your fault and it's not a bad embryo. Doesn't mean you have bad luck forever or that IVF will never work for you. It means you're still in the numbers game and actually with very good odds. One miss doesn't change that there is no such thing as the perfect embryo. One thing I get told, or at least I see online, is a lot of people saying, well, I'm not going to do PGT because it didn't work last time. And that goes back to that point. That's not a perfect embryo. PGD is not perfect. But what it does do is it reduces miscarriages, sometimes saves emotional trauma of multiple miscarriages, improves the efficiency of IVF by allowing a higher live birth rate per transfer, which then shortens the time of pregnancy. So yes, it does help. That's why we have seen the highest live birth rates ever in IVF compared to the past when we didn't use PGT8. Now, as you probably heard in the prior podcast, it doesn't make your embryos better. It's. It just helps us pick the best ones. It becomes a filter. But what it isn't is a crystal ball. And that's because there is no such thing as a perfect embryo. Sure, there are better embryos than others. Some are worse, some are better, and there's probabilities with those embryos. So when you think about pgt, what you're doing is you're improving your odds per transfer by filtering out the embryos that are not as good. But you have to remember it is not a perfect embryo. Even if it looks perfectly normal by the genetic standards. That is on the big skill. That's the guy 100ft away. Where you go, he looks normal. It's not until you look up close that you realize there's problems. Unfortunately, we don't have that ability with PGT A. So you have to make an assumption that when you transfer that embryo that the embryo doesn't have microdeletions. They're under that 10 megabit size. In the end, it doesn't matter whether you did PGT or not. Any failed transfer is hard and it's just another feeling that it's never going to work. But when you do PGT and you believe this embryo is perfect, it's even harder to swallow when it doesn't work. And then you start to think there's something wrong with you. And it could be true. As I mentioned, the uterus can be part of it. There can be other things that were not recognizing, but the other thing is it's not actually perfect. That is the lie of the perfect embryo. PGT does not make your embryos better, it just helps us filter them to find the best ones. But even then, we're looking from 100ft at that embryo, we're not looking at it close up. And so even a euploid embryo may not actually be euploid. And even if it was, we know that that it's not always going to implant 100% because there are other factors involved. Doing PGT is a personal choice. There are many reasons to do it and there are reasons not to, such as financial. But one thing is true about pgt. Even though it's not perfect, and even though it may miss those deletions that are smaller overall, it does improve your per transfer rate, it does reduce the risk of miscarriages, and it helps you get to a live birth faster. But it's important to remember the lie that there is no perfect embryo. There's just increasing your odds of having success. Hopefully you liked this episode. Maybe you're going through IVF or have and you've always wondered the same thing about pgt. How is it possible that it didn't work with that perfect embryo? Maybe you have a friend going through it. If you do share this episode with them, it might help them and hopefully it helped you. As I always say, I greatly appreciate everyone who listens to this podcast. I do this just for educational purposes. I don't make any money from doing it. So it really means a lot when you guys send in stuff to tbftewdirectionfertility.com giving me ideas for episodes as well as appreciating the show. If you like this show, tell your friends about it. Give us a five star review on your favorite medium. But most of all, keep coming back. I look forward to talking you next week on Taco Belt Fertility Tuesday.