Journal Club Global: Healthy euploid dizygotic twin birth after transfer of nonmosaic aneuploid embryos

Fertility & Sterility is pleased to once again host a  Journal Club Global. This interactive session will feature an in-depth discussion with an expert panel on the paper “Healthy euploid dizygotic twin birth after transfer of nonmosaic aneuploid embryos.”

Discussants

Ruth Lathi, MD 

Christy Tise, MD, PhD, FACMG   

Mili Thakur, MD, FACOG, FACMG 

Fertility and Sterility Moderators

Pietro Bortoletto, MD, MS, Interactive Associate-in-Chief, Fertility and Sterility

Hello, everyone. I am Pietro Bordoletto. I am the Interactive Associate in Chief for Fertility and Sterility.

It is my pleasure to be back with our first FNS Journal Club of the year. As you guys know, we try to do this on at least a monthly basis. We've done FNS Journal Clubs from meetings live, from the FNS meet, from the ASRM annual meeting.

But when we have a really killer article that comes out in FNS, we try to get the authors together as well as some expert discussants to spend some time talking a little bit more about this article beyond what you see published in the actual journal. I have a killer group of panelists today. I want to introduce the article.

I want to introduce them. And then we'll start with a little bit of a presentation briefly of the article and then jump into some discussion. I always tell people that at the end, we will leave room for questions.

There is a Q&A box that you can start to add questions as you go if you have them. And then the article being discussed is also available as a document within the chat as well that you can download the full PDF for. And if you miss part of this or if you thought the discussion was super rich and you want to share it with colleagues afterwards, this will be a podcast episode that we'll make available.

And the video will also be made available after the fact on our website. With no further ado, let's go ahead and get started. Today's article that we're discussing was published earlier last year in FNS.

It's entitled A Healthy Euploid Dizygotic Twin Birth After Transfer of Non-Mosaic Aneuploid Embryos by first author Dr. Christy Tice and senior author Dr. Ruth Lathy. We have the privilege of having Dr. Tice and Dr. Lathy here today. Dr. Tice is an assistant professor at Stanford.

She's a medical and biochemical geneticist and she directs the Reproductive Genetics Clinic at Stanford. As well as Dr. Lathy, senior author of the paper, Dr. Lathy is a reproductive endocrinologist, professor of OBGYN and the division director of REI at Stanford. Welcome, Ruth and Christy.

It is wonderful to have you guys here at the end of your day on the West Coast. Thanks for having us. We also have a expert panelist.

There are not many reproductive endocrinologists that are double board certified in medical genetics. We happen to have Dr. Millie Thacker, who's an REI geneticist. She's an associate professor at Michigan State and the physician founder of Genome Ally, a telemedicine genetics company.

Millie, thank you for joining us. Thank you for having me. It's a pleasure.

We have so much to discuss, but to be able to set the stage on the topic adequately for people who may have or not have read the article. I actually want to turn it over to you, Christy. I understand you have some slides to help kind of guide through the discussion and just present a very interesting and timely case to the audience.

Yeah, absolutely. How do these look to folks? They look perfect. All right.

Well, thanks again. My name is Christy Tice, one of the medical geneticists here at Stanford. And, you know, if you haven't read our paper, I think you should.

This was a paper that really is the culmination of a lot of years' work and a multidisciplinary effort to kind of reveal to the field something that Dr. Lachi really astutely was noticing, but also was really a patient initiated direct care to action and call to action that has resulted in a really transformative, hopefully, research study that changes the way we think about things. So, as Pietro mentioned, this was published earlier this year and essentially describes a case of a patient cared for by Dr. Lachi and the rest of the Stanford REI group that was a 42-year-old female patient and her 49-year-old partner who had presented to the REI clinic to do IVF with PGTA and desire to have another child, preferably female, for reasons that are not necessarily relevant to the scientific aspect of this case. They underwent a round of IVF and had four embryos with the following results that are shown on the screen.

I won't get into the nitty detail. They're here on the screen and also within the publication, but the crux of it all is in the desire to have a female. They had three aneuploid female embryos and one euploid male embryo.

At that point in time, there was discussion about transferring the male euploid embryo, but that really wasn't the goal of this family's reproductive journey. With a lot of direction and requests by the patients and her partner and a lot of genetic counseling and consultation with the ethics department, ultimately, there was a push to try transferring these, quote, aneuploid by albeit a screening test, despite the name PGT. In a way to at least give it and make the family feel as though they gave it their best shot to have another daughter.

To some degree, all at the time, and this is prior to the recommendations for single embryo transfers, but all were transferred and the idea and thought and highest probability was that if anything was to take and result in a pregnancy, including a healthy pregnancy, it would be the euploid male and the family was well counseled on that outcome and okay with that outcome as well. As you can imagine, this is kind of where ethics and things stood at the time with a lack of guidelines guiding how this should be done at the request of patients initiating this request. At standard practice at the time was to discard all non-euploid embryos and so kind of what I've described here, they ultimately sided with the REI team sided with ethics and the idea of reproductive autonomy and after extensive counseling underwent transfer of all four embryos.

And what happened was a dizygotic twin pregnancy with dichorionic diamniotic twins, twin girls delivered vaginally at 36 weeks and two days of gestation following PPROM. The two girls underwent genetic testing postnatally with a karyotype along with chromosomal microarrays that showed they both are euploid females and through the chromosomal microarray able to show that they are indeed dizygotic twins. They're now seven years old and doing really well with no developmental problems, which kind of led to the beginning of the study, which is featured in this article called Tame the Transfer of Aneuploid and Mosaic Embryos.

Recognizing that if it wasn't for the push provided by this family and honestly ethics and REI clinic and willingness to listen and learn as the field evolves. They wouldn't have the two daughters that they have today. And so how often is this happening? Are there health risks involved? And how do these children compare developmentally compared to euploid transfers? And so that's what gave birth to TAME, which is the Transfer of Aneuploid and Mosaic Embryos Study, which is ongoing at Stanford.

And I think this journal club is a discussion on this topic, especially as it's kind of hot in the press right now, because PGT, despite the name pre-implementation genetic testing, is indeed not diagnostic. It's a screening assay. And so how often is this happening? How many other families could benefit from giving it a go? How many families really just want to feel like they gave it everything they have? And how many centers are willing to give patients that opportunity? And so the study is currently recruiting.

This table is in our article as to what the inclusion criteria is and how we're following up on these transfers and pediatric outcomes. And we're excited at some point in the future, hopefully relatively soon, to kind of be able to publish the results of this finding, which I will say this case is not our only case. Fabulous.

That set the stage so wonderfully for those who haven't read the article. And again, if you're joining us now, the article will be linked and available for you to download through the chat discussion here. Now that we've set the stage, let's start talking about it.

We have so many different avenues to pick this case apart, but I actually want to start at the very beginning. And Ruth, as the physician kind of in the center of this case, I'd love to ask you if you could walk us through a little bit of what that multidisciplinary decision-making process looked like. It's incredible to consider today the transfer of aneuploid embryos, particularly four embryos at the same time.

But we have to be cognizant that this was many years ago, and what we know now, we did not know then. But could you tell us what specific factors made this case appropriate for such an approach, and how has your institutional policy maybe evolved since 2017? Yeah, thank you so much, Pietro, for the invitation to be here, and to Christy and Millie for joining us for this really interesting and fun evening together. This case, we published it, the children are now seven, with the permission of the family, of course, and really the support of the family wanting to share their story.

So it's hard to remember exactly where we all sat eight years ago with PGT. At that time, mosaic embryo transfer was still quite rare and thought to be even experimental, right? And I don't know about other people's institutional policies on sort of this concept of compassionate transfer. We really felt that aneuploid embryos had no chance of making a baby based on the data that we had.

And so this, we were kind of in a debate with this family about, we really think your best shot is this male embryo. And we have a beautiful embryo here, you want a baby, I have your best shot here. Us wanting to help our patient.

The patient saying, what's the harm? If you really think these embryos are, are you ready to throw them in the trash? Why not just stick them in my uterus with my transfer? If you don't think they're going to make a baby, why won't you just let me have my wish? What I think feels right to me as a person who wants to have a baby and really has a preference for a daughter. Let me, I'm happy with a son, but if I got a daughter, cherry on top, right? So we, you know, we really took this to heart. Part of, we have a group practice, as many of us all practice in a group practice.

We stick together as a group, really, that when we have these challenging decisions, we have to discuss it as a team. And we all, either we're all comfortable or we're not. And what are we going to do as a clinic? And because it was such an unusual case, our policy is if we don't have 100% agreement amongst the physicians, which as you might not be surprised, there were some debates.

We bring it to an ethics consult and we learn so much for our ethics consults. If this case is, teaches us nothing, it's really the value of our ethics colleagues, as well as our genetics colleagues. And coming to these really challenging decisions around PGT when the outcomes are not what you expected.

And, you know, we have, as a group, have come together on a handful of these unusual cases where we may have transferred an embryo that some, in some circumstances, we might've thought was not the right idea. But then you come around by talking through this with your colleagues in both of these other fields. So as long as MFM was involved as well, our ethics colleagues really helped us frame the decision around do no harm, autonomy, justice, equity, and then helping us to just frame this decision and get comfortable with it on that, using that paradigm.

It's not the first and it's not the last time where I, you know, supported a patient that requested something that I would not have wanted for myself in that circumstance. So it was a good reminder that, you know, we're not treating ourselves, we're treating our patients. So there's a lot of words on that, but certainly was a good learning experience for us.

Every step of those challenges, every question that you all are having, we probably had too, and really helped us create this framework for how to move forward with subsequent requests for abnormal transfer. And then the goal of sharing our outcomes in a prospective, inclusive way with others was how the study came up. Okay, so we came up with this idea, we're going to do it under certain circumstances.

And now after we reach our 200 transfers, we'll be publishing it so people have a, this isn't, is this a one out of 200? Is it, you know, how many out of 200 will end up like this? So we'll look forward to sharing that. I think this leads into the next logical question now that we've understand the circumstances that allowed for this to happen. Let's talk a little bit about an elephant in the room, a question that I think a lot of us have on our mind and I had as we were reading it, which is the genetic identity confirmation of these embryos.

And are these twin girls who we think they are? And are they from the embryos that we thought we placed in the uterus? So one critical question about reports of live births from aneuploid embryos is how can we definitively confirm that the transferred embryo and resulting children are genetically the same individual? And in the modern era, we have tools at our disposal to be able to do that through DNA fingerprinting using surplus amplified biopsy DNA is one way I think to tackle some of that uncertainty that people have. Was this performed in this specific case? And if not, why not? And Chrissy, I'll ask you that question. Yeah, my understanding in 2017, in the time at which this was happening, that wasn't on anyone's radar necessarily or happening.

There were, you know, given the outcome of this outcome and the karyotypes being normal, you know, that's what led to the clinical chromosomal microarrays being ordered, which did give us enough information. But they got to a point where appropriately so, and we see this in genetics all the time, that families don't want to find a problem in their otherwise healthy appearing children. And so, you know, I think by the time these twins were born, they were beautiful, they were healthy, they had normal karyotypes, even as far as a normal chromosomal microarray.

The family wasn't really interested in additional evaluation in the absence of developmental or growth features, which at seven, they still continue to not exhibit. But it's a good question. You know, it would be nice to go back and know which child, you know, was from which embryo.

And of course, the question of are these two beautiful girls even from any of these embryos, could there have been a natural conception? Twin gestation, dizygotic twins, when we are knowingly transferring three female embryos that happen to have PGTA, you know, I don't think anyone would question this had they not had PGTA. So, which a lot of people don't choose to do PGTA. And I think this speaks to that as well.

So, but it's a good question. And it also speaks to a recent episode on The Daily that probably people who are chiming into this podcast listened to last week of, you know, should there be DNA fingerprinting, not only for things like this and clarifying the limitations and challenges of PGTA, but just the limitations and challenges of assisted reproduction in a world where there is human error so that you don't bond with a child who is actually the genetic child of your neighbors down the street who unknowingly is carrying your own embryo. To drill down a little bit on are these children from the embryos that we thought we had, Ruth, before we logged on, we were talking a little bit about the frozen embryo transfer protocol for this specific case.

Could you share a little bit with the audience on what transfer protocol was used for this case and what the TAME study almost now requires by nature of how it's organized? Yeah, so in this case, again, we were not anticipating this outcome, so we didn't put the guardrails in that we probably should have that you're all asking for. We do, this wasn't a natural cycle frozen transfer. We do counsel our patients to avoid intercourse during those times and shed a single follicle.

So, again, anything's possible. Our patients don't always, but again, at 42 with all of her history up till then, very unlikely, but never say never, right? Guardrails for our study are a couple. One is a lot of the patients who are coming to see us for the TAME study are from far away or don't have regular cycles.

So the majority of the patients in the upcoming cohort will be in the program cycle. And we are only doing single embryo transfer so that we are better able to answer which embryo led to the live birth. So it is not as easy in a retrospective fashion to get DNA from a PGT lab if it's not part of a prospective study, right? These are patients who tried everything else, then are coming to us and could have had their PGT at any number of labs that may or may not still have DNA.

So it's been, I don't anticipate that's feasible in the nature of the study that we have right now, but we are putting significant guardrails in place to ensure one embryo at a time, as well as using primarily program cycles. To that point, if I had to, maybe we'll poll the three of you, knowing that four embryos returned into the uterus, if you had to guess which embryo or embryos resulted in these children, we'll never know for sure, at least in the current, what we know currently about these twins. But if I had to push you and you had to put your money in one of these embryos of those, thank you, Chrissy, for sharing it up on the screen, which one do you think, or which ones did the job? Ruth, I'll ask you first.

Yeah, well, when all else fails, go back to our standard criteria. I would go probably with the higher grade embryo first, more likely to implant based on its grade. And then just what we've learned since this study is that segmentals are probably more likely.

So I would probably go with, I don't know, top to bottom two and three. And our genetics expert here, Millie, also has done some research and talking to labs. It's unlikely that the sex chromosomes were off, but that's also a possibility, a better graded euploid male embryo.

Part of me wonders about that, but I think that technologically, it's probably the number two and three. I don't know. What do you others think? Chrissy, your thoughts as the... Well, I'm interested in Millie's thoughts too.

I will say the sex reversal part, I feel like in the absence of any additional testing we've done our due diligence with the exception of like a 300 fish studies looking for Y chromosome material in these young girls. They are both karyotypically female and chromosomally microarray from a female with no SRY material detected. So I don't give much credence to that.

I think what is interesting to me is that two of them have monosomy 18 on the prenatal side of things. We're definitely seeing that regions of homozygosity, which can just be due to shared ancestry, are causing positive cell-free DNA for monosomy disorders that are not actually present. So we're seeing that with 22q deletion syndrome being picked up as well as false positives for monosomy X. And so the fact that two of them have monosomy 18 and they're related siblings does make you wonder, is this just like a region of homozygosity shared from distant relation in the parents where the snips just happened to fall? But to that point, you know, what it does stand out is that none of them here are trisomy, which, you know, I'd love to hear Millie's thoughts and expertise on the screening aspect of monosomy and the positive predictive value comparatively to a trisomy.

Millie, your thoughts. We all want to know. Thank you.

I think I want to back up a little bit. I don't want to commit to the children to be from these embryos. I think we need to back up a little bit and just for the audience kind of dissect out some of the points that, you know, most of the PGD scientists would kind of bring it up.

So one of those things is like, what are the other reasons of these embryos resulting in a euploid birth, right? So one of them, I think that we need to kind of back up and say is how the reporting was happening back in 2017 for aneuploidy. What was the cutoff for the lab? And from the paper, my understanding is this was like a next-gen sequencing based test. At that time, most labs were not adding any of the single nucleotide polymorphisms.

So I think it's very interesting to kind of know that these are whole chromosome aneuploid embryos with the current cutoffs that are being used because PGD has evolved over time. Labs have had very rigorous control and euploidy in many of the studies where embryos were re-biopsied in different portions. They are very concordant results.

95% of the time, it matches up. If it's an aneuploid result, it's an aneuploid inner cell mass. It's pretty obvious.

So I think one of the points that we should discuss as a group is mosaicism, high and low mosaicism, and segmental aneuploidy, and then whole chromosome aneuploidy back in 2017 with the limitations of what we had then, what we knew then, and how the results were called. So that's one of the things. The second thing is what you already brought up, Petro, the genetic confirmation, DNA fingerprinting, because for those in the audience who work in a PGD lab, labs take their discordant results pretty seriously.

They basically would want to do DNA fingerprinting to say that this is not a spontaneous conception. This is not like an embryo mix-up at the embryology lab level, and this is not like a laboratory handling error. These embryos are the embryos that we're thinking they are.

So that's another thing. And then comes the point of true biological explanation of this. And that's where we say, okay, there could be a discordance between trophectoderm and inner cell mass.

We are biopsying the trophectoderm, and then the inner cell mass develops from a different cell line. There is a great paper from Bianchi et al., which shows how these lines kind of come through. So that would be an important thing.

And then the post-implantation self-correction, which is what we are thinking this is at the end of it. If we are saying mosaicism has been ruled out, segmental aneuploidy has been ruled out, embryo genetic confirmation, DNA fingerprinting is exactly how it is. It wasn't discordant between an aneuploid inner cell mass and trophectoderm because we are saying these are true aneuploid embryos.

Then you come to the point of like these embryos self-corrected themselves, and it is not representative of it. And if you get to that point, and you've dissected all of that, then you can say the monosome 11P could be one of those other embryos. And then the other ones, you know, I'm not sure how we factored them in and put them there.

But I think for everybody, the most interesting piece that needs to be solved in all of this is the calling of the aneuploid test results at the time, and that these embryos are truly non-mosaic embryos. And the answer to that question would kind of help us move forward with the thing. Because the important point I take home for all the audience, which involves, you know, the scientists in the field, doctors in the field, is PGTA test results.

Even though we think it is a screening test, it's a very different, unique kind of test because there is no diagnostic test for it. So it's not truly a screening test. When we do screening tests in any other field, you get to do a diagnostic test.

Like, if you did an IPT, you could do AMI or CVS. In a PGT test, PGTA test, even though we are calling it a screening test and you should do a diagnostic test in pregnancy, your decision making is not happening before the diagnostic test has happened. So the gravity of a PGTA test result, as you would kind of get from the audience, for the PGT scientists, they take this pretty seriously for the calling.

And over the years from 2017 to now, I think our stringency has improved. The only thing I want to add to that, all of those are excellent points. And, you know, the technology being very different than it is currently.

But I definitely want to push back on the screening versus diagnostic. I think the amnio or CVS in itself, which in for PGTA, I wouldn't, you know, we see 4000 prenatal cases and perinatal genetics here a year with satellite clinics. You know, for PGTA, aneuploid, mosaic, just non-euploid embryos, I would never recommend CVS to confirm, mainly because CVS, in my opinion, from a chromosomal standpoint, actually isn't a diagnostic test.

It's a screening. It's great for familial variants and getting that information sooner. But decision to do an amnio itself is a huge decision for a lot of families.

The number of cases and patients I see with multiple congenital anomalies, high, high, high concern for a genetic condition who, you know, declined genetic testing simply because an image of a needle going into the belly is shown to them and the risk of a wanted pregnancy being lost is stated. It in itself is a medical decision that this test from that perspective is a screen for. And whether or not it was meant to be used on the broad scale population level at which it's being used and kind of as a, you know, almost automatic add-on in certain clinics, you know, I don't think that was its intention.

But what we have done, I think what I want to say is in PGT, we have evolved to a point where actually we are picking up diagnostic things in the embryo and then looking back at the parents. So any of the tests that are now based out of SNPs, we are picking up deletions and duplications and unbalanced translocations in embryos and then saying, oh, by the way, the parents are also carriers of this. So what I'm trying to say is we are no longer considering PGTA in my mind as a screening test.

It's gone beyond that. The scientists are working really hard to get to a resolution. Like I see patients at Genome Ally, and many of them have had findings found in embryos that are chromosomal abnormalities.

And then we are looking at the parents. So a perfect example of that is a case where we had embryos, multiple embryos showing a 7-14 unbalance that was picked up by a PGT platform that also had some SNPs in it. When we looked back at the karyotypes of the parents, they were normal.

And then I pushed back to the lab and I said to the karyotype lab, we are seeing it in multiple embryos. It had to be coming from one of the parents. They looked back and then reviewed the slide and they found that one of the parents is a carrier of a 7-14 telomeric translocation, which is not picked up very easily on karyotypes.

So what I'm trying to say is no longer are we relying on PGTA as just trying to figure out a better embryo. I think the labs are pushing towards now ruling out the worst embryos. It's to be deselecting the abnormal embryos has become its role instead of saying picking the best embryo, which is not the job of PGTA.

So PGTA is now for deselection of non-viable embryos. And that's why we are more and more transferring segmentals and mosaic embryos and other things as we learn as we go. I don't disagree with all of those things in this world of genetic testing where we don't know the limitations and incidental findings.

But what you're describing to me are incidental and secondary findings of PGTA. It's not the intention of the test. And if you want to evaluate a parent for a micro duplication or micro deletion, PGTA is not the test to identify that.

A chromosomal microarray is. Yeah, which I totally agree. But the PGTA is now picking it up incidentally.

Correct. But I would also argue it's maybe picking it up and you're screening for the best embryos in cases where they're lucky enough to have a ton of embryos to choose from. But for those individuals who are presenting to REI for the eye and REI with infertility, they don't have that option to, you know, hundreds of embryos to choose from and consider PGPP and all these other things like that.

I think it just goes back to the intention of the test and what is the intended purpose that it was developed for compared to the use in which it's being used in clinical practice. And I think PGTA is a perfect example of the intention for what it was designed for, not being used for how that intention is not how it's being used in clinical practice in most places. And that's because I think the clinicians need to understand that PGTA is very good at deselecting non-viable embryos.

It's not good at selecting what you want to transfer. So what I'm trying to say if it's an aneuploid embryo, studies have shown, including Tiggs et al., that it's a 0% live birth rate. And if you extrapolate it to a bigger population, less than 2% live birth from an aneuploid embryo.

So the take-home message from current PGTA labs is if they are calling it an aneuploid embryo, it's very likely that it would not lead to a live birth. There is no doubt about that. I think the science is pretty clear.

I think euploid embryo call is also pretty robust. It's the mosaic or the intermediate copy number variants. And by the way, we should get away from saying that embryo is mosaic.

It's an intermediate copy number variant, which is a technical estimation from the lab that we need to understand and be able to counsel our patients to. It's a technical aspect of the test and not a true biological representation. As you know, in prenatal world, we don't see mosaicism of 8% to 10%.

We see it like 1%. Yes, we do. Yes.

No, we do now with fetal exome sequencing and parental controls, the labs have gotten very good. But I will say that 1% case that you're talking about, Millie, is this family? Yeah, maybe. between like IVF laboratories as well as PGT laboratories.

The technology varies widely. Their thresholds for calling things are variable. And one study in one lab of 100 good prognosis patients doesn't represent every single infertility patient in the United States or in the world.

And what we hope to help elucidate is that there are variances. And this is a real world problem. Not everybody is a good prognosis patient with a normal ovarian reserve and 34 years old.

This is a real world problem where a lot of patients are getting entire batches of embryos that are listed as aneuploidy and they are told they should do donor egg. And sure, these embryos are low potential, but I think that we have to do more work before we say no potential. We cannot say these embryos are non-viable, and we cannot say with 100% certainty that these embryos have no possibility of being truly normal children.

So this case and this debate that we are having is we want certainty. We want 100 or zero. In reproduction, if anywhere else, we have to understand there are nuances.

There's going to be exceptions to every rule. And putting the patients at the center of it, we have to give them unbiased counseling and support to make improbable decisions and to consider these transfers if they really, really want to. And that's what their heart is telling them to do.

This is entirely driven by patients who want to do this with this exact question and forcing us to answer this question for them. I think that leads into the big point of how these transfers entame. We're just allowing these transfers to happen.

The patients continue to pay for all of their care. It is an unfunded study. I think, Ruth, to your point, I think then the onus lies on the clinicians to be doing a pre-test genetic counseling before offering PGTA.

I think it's a better option for the patient to know up front that if they are 44 years old, what is their likelihood of finding a euploid embryo in one or many cycles? And on top of that, if they want a certain gender, if they're going to be low-reserve patients, in that case, it's better for them to not do PGTA as an option than to be able to then find out the test results and then putting their doctors and themselves in a very awkward and difficult situation and then taking an euploid embryo and transferring it. I think it's a better option. And I think the onus lies on the clinicians to be able to tell their patients pre-test what a test can do for them.

Because even for clinicians, it's really hard to get the ethical clearance sometimes to be able to transfer. You might have to move your embryos to a different clinic that does those kind of transfers. I think that framework has to be developed.

And that brings us to the point of the pre-test genetic counseling and the importance of the patients being partnered at that stage, rather than trying to find out that their test didn't do what they were hoping it would do for them. From a research perspective, the TAME study, which we've kind of all alluded to and we shared a little bit about at the beginning, is incredibly pragmatic. These embryos are created at different labs from different times and places, different stages of the development of the genetic testing or PGT testing.

How will the study address the potential selection bias inherent of a non-randomized study of highly motivated patients? Can you control for it in this kind of study design? Because one of the worries that I have is this is a very interesting and meaningful case report. But now what if we have 200 pragmatic case reports aggregated together without the bells and whistles that I think all of us would love to see, where they're all medicated cycles without the potential for concurrent ovulation, that there's fingerprinting done for all of the embryos to ensure that the embryo that went in is actually the child that may or may not have developed. How do you get ahead of that concern, Ruth? Well, we are open for funding.

If it has a couple million dollars, we estimate that study would cost a lot of money. And this is unfunded. And it is, like you said, pragmatic.

I worry, honestly, Pietro, about bias the other way, right? Tell us more. You're worried about, we are biased because we have these people who are highly motivated. But why are they highly motivated? Part of the data we will be collecting is to show how many prior failed transfers they've had, how many egg retrievals they had.

These are not first-time IVF patients, by and large. They have tried everything else. Except this one was, right? This one was a transfer-naive patient with no true inferences.

Yes, this was. But the study will incorporate a much worse prognosis population. I'll just put that out there.

There was a really nice study that came out in JARG, not JARG, AJARG, right? Not too long ago about blinded mosaic transfers. And they talk about how the study of being blinded on your first transfer versus using these embryos as your last transfer could impact the success rate based on just your selection of who made it to the end of their cohort, right? So I think there could be biases either way. We are by no means trying to debunk PGT in this study.

What we're trying to do is help give those families who are in a situation that seems impossible to them, where they feel they've tried everything else, but they really want to give one more transfer or something like that, and they don't have the choice. So it really is applicable to people who are considering this because they don't have the option of a euploid embryo, because they aren't interested or comfortable with donor egg for one reason or the other. So it is for those patients who don't have a better option.

Part of our counseling is always to say, you will be better off with a euploid embryo than an aneuploid embryo. If you can do another cycle, or if you can consider donor egg or whatever, wherever we think the source of these aneuploidies are, you will have a better chance of pregnancy. That is a core part of our counseling, that we expect this to be low, yet we are having patients travel to our center from all over the country, even some internationally, because of their very, very strong desire to do this.

So the pool of patients will be our job to describe that in the paper. Who are these women and their families, and what would we have expected if we did have a euploid embryo in these situations? One of Christy's students is also doing a review of the patient experience, so a qualitative assessment of this patient. So do people regret doing this transfer? Do they feel closure? So our goal is to make our patients feel better, and is this option making these patients feel better? I think that will also be an interesting project as an adjunct to this, is that we're trying to protect our patients from harm.

We don't want them to have to go through another failed transfer, but what do they think? Yeah, and I will say, you know, because this study is unfunded, my students' research is likely to be published before TAIM is, on the feelings and qualitative recorded thematic aspects of interviews with people who have participated in TAIM, and having, you know, getting to sit in on her committee meetings and see the preliminary data and the themes that are emerging. One, it's fascinating, you know, the makeup and demographics of these couples and families, you know, ranging from where they live to their age to what number cycle, how many kids they have at home, cisgender, transgender, homosexual, heterosexual, all of the above, is quite fascinating. And I think the stories that really come through are, regardless of the outcome of TAIM, whether they left with a healthy child or not, they are incredibly thankful that someone gave them the opportunity to try.

And that's where I think genetic counseling, back to Millie's initial point of pre-test counseling, you know, as someone who teaches and is the medical director for the genetic counseling program here at Stanford with 15 trainees a year, they probably get more reproductive genetic counseling curriculum than anywhere else in the country, just based on who's teaching them. But this is really an interesting area of ethical research and counseling. But I feel very strongly if a clinic is going to offer PGTA and you are not going to allow someone to transfer aneuploid embryos, you need to make sure that is abundantly clear to them before they do the testing, not at the time they get the results and want to move forward.

That's a great point that I think is often lost on us where we do PGTA expecting that there's going to be a useful embryo in the mix. But like you said, when they end up with, as far as we know it today, not useful embryos, embryos that have been deprioritized for transfer, there is a lot of friction there for patients and clinics. We have 15 minutes left.

We've had a bunch of questions come through the chat, and I want to turn to those for a moment before our time's up. There's a couple of notable people here in the Q&As, and I actually want to take Dr. Viotti's question. Many in the field are familiar with his work on mosaic embryo transfer.

And his question is, scientifically, there are too many blind spots in this study. Not having funding should not be an excuse for publishing something that is not validated. Could you not team up with a PGT lab to cover the DNA fingerprinting? I'm sure in the Bay Area you've been approached or have thought about a corporate partner with one of the labs, or haven't you, Christy and Ruth? I think we're open to it.

Believe it or not, I mean, we don't get invited to like the JPMorgan events in the Bay Area just because we live here. I think the research Ruth and I are doing is very exciting and is very fundable. But it's not as though donors are knocking down our door.

And that also, to the point of this being patient-initiated and patient-driven, these patients are coming to us from all over the country when they've been told no from elsewhere. And so what clinical testing has happened prior to them getting to us, which lab was being used, if DNA fingerprinting was done or not, is somewhat out of our control with this prospective study. To do a purely randomized trial with a single lab, which of course would have its own biases, to Ruth's point, would cost millions.

But we'd be open to discussion. A couple of other questions in the chat that I'll kind of try to aggregate into a question. Millie, if you could talk to us a little bit about the platform.

This was a next-generation sequencing-based test in 2017. The current state of affairs for patients considering utilizing PGTA in 2026 and beyond. What do we know now based on the platform selection that we didn't know then? And what are the existing limitations of our most modern PGTA platforms? So the core PGTA platforms, most of them use next-generation sequencing, and it's a low-pass next-generation sequencing where they do copy number variants.

And then the analytic part of it is to call the results, and they are called based on the percentage of cells that are showing different things. So most labs are using the cutoff between 20 and 80 percent or 30 and 70 percent. So euploid embryos would be less than 20 percent or less than 30 percent in different labs.

And then for aneuploid embryos, the call of the aneuploid in the copy number variant graph happens when it is more than 70 or 80 percent. There are two different cutoffs for labs, but it's in the ballpark in there. And then the results that are intermediate copy numbers in the next-gen sequencing are mosaic test results or intermediate copy number variants.

They are low mosaics in most labs under 50 percent, so 30 to 50 percent or 20 to 40 percent is where they call it. And then for other labs, the other type of test result is the high mosaic, which is more than 50 percent but less than the aneuploid cutoff. Now what the labs have done, and over the last few years, more and more labs are adding single nucleotide polymorphism inside their platforms.

These SNPs can range from some labs using as little as 600 SNPs. Other labs are using a few thousand SNPs. And then there are a few platforms that are completely SNP-based platforms where there can be like 700,000 to 800,000 SNPs at different locations, and then they are calling the test results based on that.

And the main important thing is that inside the group, which is euploid and aneuploid, I think most labs are doing a pretty good job of calling those test results, and most of them will match your inner cell mass most of the time. But in the mosaic group, the calling is different. It is very specific to a lab, and that's where your mosaic embryo transfer results can differ from lab to lab.

But what we have found is all across the board, most of the labs are getting good pregnancy rates with low mosaic embryos as compared to high mosaic embryos. Then with these different next-gen sequencing and your SNP-based platforms, we are getting segmental aneuploidies. So it's not a whole chromosome that is abnormal, but the copy number variants at a particular site are either deleted or duplicated.

And with the group out of NYU Langone, they have done a lot of transfers with the segmental aneuploid embryos, and what they have found is that they had like about a 20% pregnancy rate. So between 20% to 30% pregnancy rate with segmental aneuploid embryos, there were studies that showed that this could develop as a mitotic event. And so segmental aneuploidy in itself is another situation that different platforms are having different resolutions.

A SNP-only platform, which has 700,000 to 800,000 SNPs, are actually going down to the resolution of 5 megabases and picking up deletions, duplications, loss of heterozygosity, or regions of homozygosity, and uniparental disomian embryos, which is like really another set of test results that we can get. So the bottom line of all of this is for any clinician that is going to use PGTA as a tool in their clinic, they should know how their lab is calling results, what does those results mean, and then also provide the pre-test counseling to the patients. Like when I counsel my patients, I'm very clear to them, you know, this is what euploid would mean, this is what aneuploid would mean, you know, how we will deal with the mosaics and what we feel about it.

And there was a recent study last year, which I wrote a commentary for in FNS, where they showed that about 30% of your low mosaic embryos can still have meiotic abnormalities. So what we are trying to do in the PGT world is to sort out the intermediate copy number variants, and that is where the platforms will differ, that is where the rigorousness and validation from lab to lab is going to differ, that is how the reporting is going to be different. There are some labs that are reporting out whole chromosomal aneuploidy as one group, and rest of everything as one group, while there are others that are still reporting out euploid, aneuploid, low, high mosaics, and segmental aneuploid separately.

So I think two things need to happen in our field. One of them is a very good pre-test counseling, setting expectations for patients, allowing only patients who will benefit from the testing to do the PGTA rather than doing it everybody. Like, I would rather have a 44-year-old patient who is set on doing IVF, do a transfer of an untested embryo, and then do the NIPT and find out what is happening versus find out you have three cycles of aneuploid embryos, and then try to transfer an aneuploid embryo, which puts the clinic at risk and the patient at a really high risk of a prenatal outcome that may not be conducive, right? So I think pre-test counseling is one thing we have to focus on.

Our word wish to the patient of not saying these embryos are normal and abnormal instead of, like, telling them what it means that we are saying. And then, you know, the second thing is for us to be supportive of what we are looking in our PGT lab. If clinicians ask for validation of the test and analytical validation and clinical validation, like, we as clinicians should be the stewards of a product that we used on our patients instead of clinicians following the lab.

We should partner with the lab, understand what they're offering, and then, you know, letting the lab rise with us. Our patients get the benefit, and we are the stewards. Instead of the lab just bringing up a new platform, you jump on it, and then you find out, oh, they were calling the results a certain way, but we were telling the patients another thing.

You know, it's like, as a clinical perspective, we have to gather together all doctors. We have to decide as PGTA for our patients. I think we have that ship has sailed a long time ago.

PGT is here. It's here to stay. It's not going to go away.

So we need to just, like... I think there's a lot. You said a lot. And I have so many wonderful thoughts about, you know, agreeing with you on so many of those things.

I think what makes us great as a field is that we have a richness, and we have richness amongst us, and our patients all have different perspectives as well. Genetic counseling is essential, and we, you know... Christy and I will say this till the cows come home. We're constantly asking for more genetic counseling support, but genetic counseling is not one and done.

You're not off the hook just because you did a good pre-test counseling. People's attitudes change. People respond to the information that they're given, their outcomes that they're experiencing, and I think that, given the same set of data, not everyone will choose the same thing, and I think we have to realize that.

Just because we're willing to transfer an antiploid embryo doesn't mean we're upset that we did the PGT in the first place, right? We were hoping to give her a better outcome, but we couldn't. This was the best we had. So I think that that's a changing circumstance.

I was hoping for a euploid embryo. Pietro was hoping for one. The patient was hoping for one.

We didn't get it. We tried again. We tried again.

That is the common scenario that we're seeing, and this concern that we're putting the clinic at risk because we're allowing the patient to transfer the embryo that they want to transfer, I think it's fear that is unfounded. I think with proper counseling and with obvious attempts at trying to get her a better outcome, we are not putting ourselves at risk, and that is something that we have to kind of reexamine. We may not be comfortable with it, and that's different than saying, I'm afraid she's going to sue me because I gave her what she wanted.

As long as we are counseling and giving them all her options and alternatives, I would push back on, I don't think that's a risk, and I think that we need to be careful about saying it's putting us at risk because that will be shying away from things that patients really want. Ruth, I congratulate you and Christy for taking care of this very special group of women, right? We are talking about two separate groups here. What we are talking about is one group is the one group that's already done the IVF, has aneuploid embryos, and wants to transfer them, or abnormal embryos, mosaics, or segmentals.

That's a different group. But for the prospective patients, like the patients coming in the next year to the doctors, I think the doctors can learn from what we have learned in the last few years and then set expectations, right? If you have a 44-year-old with a 0.2 AMH, you're not going to get an euploid embryo just by doing IVF. It takes about 40 eggs to get to that level, right? It's like they're not going to get 40 eggs in any cycle.

It would be five, six cycles of failed IVF, and then you're doing the... It's not the lab. So basically what I'm trying to say is the technical aspect of PGTA and the clinical aspect of PGTA has to be balanced, and that balance is not with the lab. It's not with the patient.

It's with the clinician. We are the doorkeepers of saying PGTA is for you or it's not for you. I would honestly tell a patient who is above the age of 40 with a low egg reserve or has a few failed cycles from another center, our patients are vulnerable.

They want to look for that hope, but as a clinician, I can probably tell that they are going to get a euploid embryo or they're not going to get a euploid embryo. And on top of that, some of our patients want to put PGTA and PGTM. That's not going to happen.

We are not going to get an unaffected PGTA embryo that's euploid in somebody with a low reserve and an advanced maternal age. It's not the lab calling it differently. So what I'm saying is what you're doing with the TAME study, what this case is all about is a different group of patients.

Those are the patients who have already taken the decision. We have abnormal test results. We've got to give them the autonomy, give them the counseling, be supportive to them, and let them do whatever they want to do with their embryos and not unnecessarily discard the embryos.

But going forward, how can we do it better? Millie, I hear you, but I think to me what this study represents is kind of what you're describing, which it's okay that we disagree, but for so long geneticists have been the gatekeepers of genetic testing. That's why we have six- to eight-month wait lists. And we are in a world where we are not pumping out geneticists fast enough.

We can pump out more genetic counselors. It's a two-year program, 15 a year, multiple centers, way more than the 20 programs that pump out two geneticists a year, many of whom go into industry and not practice medicine. But I think this paper to me represents the epitome of kind of what you're saying, which you're using, and I recognize that geneticists are just, we live in the land of never say never, and anything can happen.

And so we're more familiar with not using absolute statements, but the absolute statements of you're looking at a 47-year-old woman and you know you're not going to get something, I think I just inherently don't agree with that mindset of you as the physician know better. And so I think that is where being gatekeepers of this test, I don't agree that it lies in the hands of the clinician. I think it all needs to be shared decision-making with appropriate pre-test counseling.

And what you might decide if you were in that scenario may be different than what the identical version of you in a slightly different scenario may decide, or even the same version of you five years from now, when you've had a reason that all of a sudden you do want another child, whether it be the loss of a spouse or a number of other reasons. So I think to me what you're describing is a world where clinicians continue to gatekeep genetic testing of who decides to get it and who doesn't. I think the world we should aim for is a world where we offer clinically valid, CLIA-CAP validated evidence-based genetic testing to anyone who wants it, and we are not gatekeepers of that, but we are familiar and we provide them with the appropriate genetic counseling to ensure that they are well aware of the risk and limitations and those are all documented so that when we look back on the outcomes, we can say that we tried our best to inform them in that period of time, even if it's in 2017, which really doesn't seem that far away, but in the world of REI and definitely the world of genetics where we're now doing genomes on fetuses, it's very, very far away.

I think that is a wonderful way to conclude an hour that should have been two hours because I think we have so much more to discuss. I want to thank the three of you for spending time at the end of your busy day to join us. I want to thank the participants for logging in and listening.

Clearly there's more to discuss. I know that there are commentaries coming out on the published article. I invite everyone who has additional thoughts that they want to share to submit their own letters to the editor.

Some of them do show up in main FNS. Some of them will show up in the Consider This section of Fertility and Sterility that lives in front of the paywall and can be easily disseminated with colleagues who are not FNS subscribers, but clearly this is a super timely and important discussion. We've, I think, done our best to pick apart some of the pitfalls of genetic testing, some of the pitfalls of this specific case.

But I think I speak on behalf of all of us. We're all eager to see what the same study shows. We can't wait for you to finish enrolling the next hundred so we can see those results sooner rather than later.

For everyone who caught part of this or wants to share it with their colleagues, as a reminder, this will be available as a podcast episode and the video will be available on the internet. I'll conclude by saying thank you again to the listeners, thank you again to the panelists, but also thank you to this family for allowing us to share their story, both in this article and on this podcast. That's all the time we have for tonight.

Thank you all, and we'll see you again at the next FNS Journal Club Live. Thank you. Bye.

Thank you. Have a good evening. Thank you.