Journal Global Club From TSRM 2024: Preimplantation genetic testing for aneuploidy in unexplained recurrent pregnancy loss: A systematic review and meta-analysis

To explore the effectiveness of PGT-A in managing unexplained recurrent pregnancy loss by evaluating several key aspects:

1. the likelihood of a live birth in a subsequent spontaneous pregnancy,
2. whether women with unexplained recurrent pregnancy loss have higher rate of aneuploidy,
3. whether euploid blastocysts offer comparable live birth rate in patients with unexplained recurrent pregnancy loss,
4. whether the endometrium is less selective in unexplained recurrent pregnancy loss, and
5. whether PGT-A increases live birth rate or reduces pregnancy losses until delivery. 

I would like to thank everyone for being so late today. I know it's been a long journey for you, a long day for you. I would like to welcome you for this Global Journal Club for Fertility and Sterility that will present a paper which was written by one of your own.

And today we have distinguished experts and investigators here with me to join me for this debate on this paper. So I will start introducing Professor Barbara Lawrenz that has actually wrote over 100 peer-reviewed papers. Her expertise is in preserving fertility for women, undergoing cancer treatment, and offering hope for these patients.

Also, I would like to continue with Dr. Ginsburg, who is actually the president of American Society of Human Reproduction and the past president of SART. She's a professor of OBGYN and reproductive biology at Harvard Medical School. And she actually was the former medical director for Harvard Medical for Bergeman Hot Women Hospital in Boston.

Also, I would like to continue with Johnny Awwad. I have to just, the resumes are so big, and I have to look. Actually, I checked GPT-1.

So Dr. Awwad, Johnny Awwad, is a distinguished fertility consultant with over 25 years of experience in REI, and he currently serves as executive chair of women's services and division chief of reproductive medicine at Sindra Medicine in Doha, Qatar. And then I would like to continue with Santiago Munne, who actually has, in his introduction, he was one of the first to develop the PGT-A testing for aneuploidy back in 1994. And actually he won SART prizes.

And currently he works in genetics in, can you help me? Progenesis. Progenesis, exactly. And then I would like to finish with Henriette Svarre, that actually is a professor of OBGYN in University of Copenhagen, chief physician and head of recruitment and pregnancy laws, as you have seen her just a few hours before talking about pregnancy laws.

And actually she's leading a research group of more than 25 persons with the ambition to improve women and reproductive health. And I will finish with Sezcan Mumusoglu, who actually is a member of the Turkish Society of Human Reproduction. He was the director of REI and IVF clinic of Hacetepe University and IVF center.

And his research includes actually pregnancy losses. So I would like to invite him to present us his paper, a summary of his paper entitled PGT-A testing for aneuploidy in unexplained pregnancy losses, systematic review and meta-analysis. Sezcan, can you just present us all your data? Yeah, thank you, Paul.

Thank you for a nice introduction. Thank you for coming all. Dear colleagues, dear friends, welcome to the Fertility Sterility Journal Global Club, actually.

This is our privilege and honor to present our manuscript in this location with the expert in the field. Thank you very much for providing such opportunity to us. We would like to discuss our recent published meta-analysis and systematic review in fertility sterility in August this year.

Actually, the title is entitled Preimplantation Genetic Testing for Aneuploidy in Unexplained Recurrent Pregnancy Loss Patients, a Systematic Review and Meta-Analysis. As we all know, recurrent pregnancy loss was defined historically as a loss of three and more consecutive pregnancies, but it has recently been changed by ESHRE and ASRM. Now we are defining RPL with the loss of two pregnancies, above two pregnancies, including consecutive and non-consecutive losses, and also biochemical pregnancy losses is included in ESHRE guideline but not ASRM.

Based on the definition, the prevalence is changing. It is around one point if you use the old historical definition with three and more consecutive pregnancy losses. But if you use two and more consecutive and non-consecutive losses, the prevalence is reaching up to 3%.

Three out of 100 cases in daily life is suffering from the recurrent pregnancy loss which is not easy to handle for the psychological part and also the physical part. The etiology of RPL, despite enormous effort over the last three decades, still remains unknown in 50-70% of the cases. The objective of this Systematic Review and Meta-Analysis was to explore the effectiveness of PGT-A in managing unexplained RPL patients by evaluating several key aspects.

Actually, this is not a standard meta-analysis. We identified five research questions to handle and to make a final conclusion on the effectiveness of PGT-A managing unexplained RPL patients. This is a systematic review.

We used the PRISMA guidelines, but when possible, we did a meta-analysis based on the research question. The inclusion criteria for the studies were two spontaneous pregnancy losses including biochemical. We prefer to use the ESHRE guideline definition, but I should stress that of the included 18 studies we will discuss later on, only two of them were using ESHRE definition.

The others were used, almost one is using three and more consecutive losses, but the remaining 15 were using two spontaneous pregnancy losses for the definition. Only studies with trophectoderm biopsy were included, not cleavage state biopsy were included in this study. To answer the question whether PGT-A can benefit patients with unexplained RPL, we have to answer the following five questions.

The first one, what is the likelihood of live birth in subsequent pregnancy following miscarriages on those patients with RPL? I mean, the answer is clear, actually. It depends on the age and the number of previous miscarriages. When the number of previous miscarriages is increasing, the likelihood of miscarriages in the next pregnancy is also increasing.

As you can see, for newly gravid, it's 10%. For two losses, it is 30%. Three and more losses, it reached to 40% for the chance of miscarriage recurrence for the upcoming pregnancy.

The second question, do patients with unexplained RPL have a higher aneuploidy rate? I mean, it's interesting because are those patients doing miscarriages because of higher rate of aneuploidy in their oocyte cohort or in their embryo cohort? Actually, the initial first two studies reported higher aneuploidy rate in RPL. These are retrospective core studies having some limitation in the analysis. In the first one, the age was a potential confounder and could not be statistically controlled for the strong confounder.

For the second one, in the subgroup analysis, they identified a higher rate of aneuploidy. But when you look at the sample size, it's only 30 cases, which may misleading the conclusion because it is under the risk of type 1 error in the statistical analysis. When you look at the risk emerging data on that topic, you will see four papers.

In total, there are six papers in the literature. They are suggesting that those patients with RPL have the similar euploidy rate in their embryo cohort when compared to those with non-RPL patients. The third question, do euploid blastocysts provide a comparable live birth rates in patients with RPL when compared to those without RPL? Actually, you do have aneuploid blastocyst and transferring to that blastocyst in RPL patients and non-RPL patients and made a comparison.

For this comparison, we identified eight retrospective core studies comparing RPL versus non-RPL following euploid embryo transfer. The data, the proof data of those retrospective studies suggest that the clinical pregnancy rate is similar, almost 1, 0.97, and also the miscarriage rate is almost the same, 1.5, but the confidence interval is crossing 1. When you look at the live birth rate, it's slightly lower in RPL patients according to several studies, but there are many limitations for those studies which we identified with the quality assessment tool. When we did a sensitivity analysis with pooling the data coming from the good quality studies, you will see that the clinical pregnancy rate, clinical pregnancy loss rate, and also live birth rate is similar for those patients with RPL compared to non-RPL patients.

The fourth question is an interesting one. Is endometrium less selective for those patients? When you transfer, not the transfer, but when they get pregnant, they are allowing the embryos which are uneuploid. Are they overly receptive endometrium? To answer this question, we can use the data from the product of conception analysis, and these data suggested constantly over the last 20 years because there are many studies done by the classical karyotype using classical karyotyping, and also the recent studies using microarray, which is much sensitive, and compare the product of conception in terms of unemployed, euploid miscarriage.

As you can see, all cases, regardless of previous miscarriage numbers, have the constant number of unemployed miscarriages. It means that 50 to 60% of the miscarriages occurring due to unemployed miscarriages, but with increasing number of miscarriages, also the euploid miscarriages increasing, but unemployed is remaining constant. It means that the endometrium is likely equally selective in RPL patients when compared to non-RPL patients based on this data.

The last but not the least question is, does PGT-A increase the live birth rate and reduce the pregnancy loss rate in patients with unexplained RPL compared to classical IVF? You decided to do the IVF. All the patients are RPL, and in one arm, you are using the PGT-A. In the other arm, you don't use PGT-A undergoing with the classical IVF.

When you look at the literature, we identified 11 studies. Nine were retrospective, one were prospective, and one is randomized control trial. We did a quality assessment also for the studies itself and also quality assessment for the evidence using GREAT framework.

Then, compare the result. Per embryo transfer, not the per patient. Per embryo transfer analysis suggests that if you use PGT-A compared to classical IVF, it provides around two-fold higher clinical pregnancy rate.

The odds ratio, 1.76. Almost more than two-fold lower clinical pregnancy loss rate. The odds ratio is 0.42. The live birth is more than two-fold higher when compared with the non-PGT-A arm in the PGT-A arm following the embryo transfer, but the quality of evidence is low. Most of the studies are retrospective.

We included the 10 studies. The heterogeneity is 46%. Only four studies allow us to make the per patient analysis, which is important.

When you consider the treatment itself, per patient treatment is much important than the per transfer. But based on this data also, we identified 1.5-fold higher clinical pregnancy rate and also slightly lower miscarriage rate, but it could not reach the statistical significance and significantly higher live birth rate in the final analysis. The odds ratio is 1.85. Four studies were included.

In total, 540 cases were included for this analysis. The quality of the evidence is very low based on the GREAT framework. The limitation of the meta-analysis is most of the studies are retrospective core studies.

Also, different genetic platforms for PGT-A were used across the studies. The tests used to exclude known etiologies for RPL are not clearly defined in all studies. This is an important limitation.

In some studies, a single patient was included in more than one transfer cycle. This is a limitation, but actually, this may cause bias through the non-PGT-A treatment. But again, some patients were included with more than one embryo transfer cycle in the retrospective studies.

The conclusion, low-quality pooled data from observational studies suggests that in patients with RPL, PGT-A may increase the live birth rate per transfer while decreasing the clinical pregnancy rate when compared to classical IVF. Obviously, we need data comparing expectant versus PGT-A. This is the most important point.

There's only one study in the literature we may discuss during the discussion session comparing PGT-A with the expected management. There is no data for that. We are waiting for this, but it's not easy to do such an RCT.

PGT-A will remain a choice that can be considered on individual basis based on our findings. This is our main conclusion, actually. Who is likely to benefit most from the treatment? You may consider this is a speculation.

Actually, not related with the result, but the older patients are prone to make aneuploid miscarriages, so they may get benefit more than the younger one. Also, those patients with high ovarian reserve could reach the euploid blastocyst quicker than the decreased ovarian reserve group. Also, those patients with a history of aneuploid pregnancy losses can benefit more from PGT-A-tested embryo transfer cycle.

Thank you for your attention. First of all, I would like to congratulate you for this nice paper. I think, regardless of the limitation that it has, it's a very valuable paper for our field, and I thank you for that, and congratulate you for that.

Now, you can prepare questions. We'll take questions if you want to, but in the meantime, given that there was five questions that you want to answer from this data, I think our speakers today here have questions for you. So I will start with Barbara, and please feel free afterwards to try to give your opinion, and also ask questions to the author on what he has done.

Okay, yes, also from my side, congratulations to the authors to this very beautiful paper, because I think it's very logically, I mean, you answer those different questions. Now, we have also experts on PGT-A, so I'm not going into the different platforms, but maybe this is a question, maybe you have looked into this, but also one of further direction. I mean, you have shown this beautiful graph where we see the highest number of losses, so aneuploidy remains, but aeuploid losses increases.

So in the end, I mean, we know, obviously, that also the receptivity seems to be the same. Would we have to look more into other uterine factors? I mean, we know that the uterus is going to change with more pregnancies. We know maybe those patients will have, like, more curettage, more invasive procedures.

Would we have to look beyond the lining, for example? I mean, what is now highly discussed is, like, adenomyosis, would this be a reason for pregnancy losses in patients with repeated pregnancy losses? Do you have any data on this? Did you look into this? Thank you for the question, Barbara. Actually, in terms of constant aneuploid miscarriages, but increasing number of euploid miscarriages suggests some different things that are occurring for those cases with increasing number of miscarriages. This article actually did not deal with that issue, but for those cases, I do believe that with the number of increasing miscarriages and the surgical procedure itself, actually two papers in the subgroup analysis suggest that if the number of previous miscarriages is increasing, it might be related with the higher miscarriage rate.

Because the repetitive dilatation and curettage procedure may cause the T9 endometrium, one reason might be. And also, the adenomyosis obviously is not clearly stated with those retrospective studies, whether it is excluded or not, but might be another reason to consider for the RPR patients. But mainly from the data and from the evidence-based approach, I would suggest that the number of procedures that we did following the miscarriages could be related with the lower implantation in the upcoming pregnancy.

Is it working? It is working. Okay. So one of my questions was, was there any comment in any of the studies about embryo quality? Because oftentimes, or certainly in our practice, patients might be considering PGT-A and then if they have only morulas or their embryos don't look so good, they may opt to go ahead without PGT-A.

So I was wondering, in the PGT-A versus no PGT-A papers, was there a difference in blastocyst number or quality? Yes. I mean, most of the studies report about that. Actually, the quality of the embryo is quite similar.

But I would like to discuss with you the 2016 paper in terms of the efficacy of PGT-A comparing with the expected management, which is published in Human Reproduction by Stanford Group, actually. They compared expected management with PGT-A. And for intention to treat analysis, they reported similar result.

But when you look at the data itself, they exclude in the PGT-A, they exclude the biopsy for the poor quality embryos, actually. But this kind of bias. So when you look at transfer outcome, PGT-A is doing better than expected management and that study.

So we do know from the old studies that even the quality is poor, the morphology is not a strong determinant of euploid itself. So, I mean, on that basis, we should recommend if we decided to do the PGT-A for the recurrent pregnancy-loss patients, we should not exclude those embryos with poor morphology. We should also test them based on the 2016 studies.

This, I can say. Again, congratulations. Thank you.

This great paper. You know, I want to reset the tone back to the reason why we're looking at PGT-A as a modality of treatment for women with unexplained recurrent pregnancy loss, right? And yes, sure. So the reason is why are we looking at PGT-A, right? And the reason is very obvious.

The current treatment, expected treatment is associated with a pretty good, actually doing nothing, pretty good success rate, 50%, 70%, depending on certain parameters. The problem across all ages is this heavy psychological burden women have to go through. And we see patients who come to us sometimes in as much as their desire is to have a child, they sometimes postpone pregnancy because they don't want to deal with the loss again, right? So that's important.

But there's something even more important, equally important than the psychological burden, which is a biological problem which relates essentially to women at a later age, right? Because then when we're looking at women close to 40, right, when you tell them, try again, their monthly fecundity is no more 15%, 20%, less than 5%, so it may take them a longer time to get pregnant again. And that will compromise, it will be very detrimental to their overall outcome, right? Because with time, they're losing their number of eggs and their quality of eggs very rapidly, right? And I can see that when you talk about PGT-A, I'm looking at the whole women population, but with a focus essentially at this group of women because there's, in addition to the psychological, a biological urgency, right? And if you look at the data from Bill Kutteh, right, and you see that essentially when they looked at all these products on conception, all these genetic testing, you know, 55% were unemployed pregnancy losses. I would say one-to-one ratio to make it simple, right? One-to-one ratio.

And they found out that if you increase, so if that one-to-one stays the same even beyond three miscarriages. However, it appears to be sensitive to age of a woman. In other words, that one-to-one ratio increased to one-to-three in women who are 40 years plus, right? So this is telling us again that there is something to do over there, right? Although the working hypothesis to my mind is really trying to treat something without addressing the real problem.

So what we're trying to work is to work at the front end by reducing the exposure to the endometrium, the unemployed exposure to the endometrium, hoping that by doing that you would reduce at the back end the risk of miscarriages, the overall burden of miscarriages without addressing the real problem, right? Do you agree with that? Yeah, thank you. Let me just summarize. Yeah, I agree on that.

Well, thank you very much for this paper. That's a great review of the literature. I have a small discrepancy on the conclusion that there is basically a similar rate of unemployed in both groups, reprogrammed pregnancy loss and not, because two of the papers were comparing it to fertile population, and those found a higher unemployed rate in reprogrammed pregnancy loss.

Meanwhile, the other three were in infertile patients, and they find the same rate of unemployed. So basically to me, reprogrammed pregnancy loss patients are subfertile patients. They are more similar to infertile patients, not to fertile patients like egg donors or PGT-M patients.

In addition, if we look at the data study in which reprogrammed pregnancy loss patients do PGT or not PGT, the implantation rate is much higher after PGT. Those, the control group, obviously because we're looking at implantation, they haven't miscarried yet, right? We're looking only at implantation. If there is more implantation in the PGT group, it means that a lot of embryos are not implanting, so before miscarriage.

Therefore, they have an extra problem, right? There's a lot of embryos there that don't even implant. So the conclusion that endometrium is equally receptive, yes, but we're missing a bunch of embryos that don't implant because they were unemployed. Right, I agree on that, but regarding the unemployed rate, what's your comment? Only the infertility itself is a determinant of unemployed rate in patients, or the age is only the main determinant in terms of comparison infertile and non-infertile patients.

What do you think on that? Well, yeah, age obviously is very important, but we're comparing the same age, right? At the same age level, we are assuming that those papers were controlled by age, right? Actually, one of them could try to control with the regression, but it's not easy to control the age only with the regression in retrospective studies. So my question actually, do you believe that infertile couples, because infertility is a wide range of disease, may come from the tubal factor, the male factor. Would you say that, I mean, excluding the age, the infertile couples has much higher unemployed rate compared to non-infertile? Yeah, if you compare egg donors, for instance, with patients that are below 35, infertile patients have a higher unemployed rate.

It may interfere. It's like recurrent unemployment, like every cycle could provide a percentage of unemployment, each cycle, even though you have several cycles, or per cycle itself. Yeah.

I mean, would it be the case that infertile patients will have recurrent cycles with complete unemployed embryos? Sorry. Can you repeat? Yes, I'm sorry. Could it be that infertile couple can have cycles with complete unemployed embryos? Yeah.

And this will be something that would repeat itself throughout cycles. Therefore, this is why they always have embryos which are unemployed and therefore miscarry. I believe that only the translocation, balanced translocation may add that comparison, make difference, because those patients may be prone to be both recurrent pregnancy-loss patients and also the infertile patients.

I don't know, because three to four percent of the cases in infertile group may have a balanced translocation in the cardiotype analysis. So those patients, in most studies, tested for the cardiotype analysis, actually. So probably, I do, I mean, based on the literature, probably those patients' RPL could produce the similar rate of employed embryos for those patients with infertile, because we don't test here the non-infertile patients.

All right, as a conclusion. I would also like to congratulate you on this study. I think what you have been doing is taken a lot of low-quality studies, as you also report, and then base a conclusion on that.

What do you think, if you have had high-quality studies, what do you think would have been the results of this? I mean, the high-quality studies, this is a kind of insight, because we need a randomized site, obviously, to make the film conclusion. As you can see from my conclusion, I said it may increase the chance, because they may go the different direction, because the quality of evidence is low. So, but from the sensitivity analysis, and also from four studies, in the fifth question that we compared the RPL, and an RPL patient undergoing PGT-A, non-PGT-A, the data is given deeply that we can assess the per-patient outcome.

So, based on that outcome, I mean, comparison, I would say that PGT-A could help some group of patients to reduce the number of miscarriages by deselecting the unemployed embryos, because you can decrease the miscarriages on those kids. But we obviously need the expected management arm. Three-arm study would be perfect, including PGT-A and also non-PGT-A.

It's not maybe useless, but on the other hand, we should also have the expected management arm to make the film conclusion. But there's also the risk that you include RPL patients that had been having euploidosis for a long time, but then they grow older. What you take care of now is actually to reduce the... Yeah, actually, I mean, that's the important point that you emphasized.

If you wait a lot, I mean, the number of... The chance of catching the euploid embryo will decrease, so the time is important. Expediting the time to pregnancy is important, but no study is reporting such time issue. So, to that point, if we assume we have high-quality data and we're looking essentially at women with certain advanced age with the availability of enough embryos for biopsy, right, so the ideal situation, ideal target population, I would expect the total... the clinical pregnancy rate to be improved, increased.

The miscarriage rate to be reduced, but not reduced enough to be comparable to PGT-A for an unselected group of women, because we're not really addressing the real problem. And ultimately, the live birth rate would be improved, but not to the level of the PGT-A for unselected patients. That's my... I don't know.

That's just for... That's my expectation. I agree. So, we have a question.

Yeah. Sezcan, congratulations. Excellent paper.

Just to further emphasize what Henriette has just said, that you do bring together really poor-quality studies, actually, and it's very difficult to address this difficult problem or this difficult question with studies as such, because we know that patients with recurrent abortion are a very heterogeneous group. So, you have patients at different ages, at different brackets. You have patients with low-order miscarriages versus high-order miscarriages.

So, for example, when you take two or more miscarriages, this may be completely related to just out-of-luck chance problem, and you will not be able to improve that patient's chance of getting pregnant when you do IVF and PGT-A. As opposed to maybe a patient with five or six recurrent miscarriages, that's another question. But also, under those circumstances, most of those miscarriages will be euploid, and PGT-A will not further enhance the chances of a pregnancy.

So this is a very difficult question to address. I agree. And in the future, I don't believe any good-quality studies will come along.

The reason being is it's just like the fibroids, for example. Fibroids, otherwise unexplained infertility, you remove them, you increase your chances of pregnancy. Is this a fact? No, it's not.

Because patients have different sizes, different locations, different problems, different age brackets, different everything. So very difficult to address this question, and I think this is the best that can be done at the moment. And I do agree with Johnny and with his recent conclusion that even if you do conduct a good-quality study, that is the most that we are going to get.

Thank you for the comment. I agree on that. I mean, deselecting the embryos could help the patient in a small portion of all miscarriages with increasing number of miscarriages.

Based on the diagram that I showed, as you can see, euploid miscarriages increasing for those patients above 5, 6, 7, 8. We don't know what's going on on those patients. It's not easy to make a subgroup analysis for that. But two studies suggest with the increasing number of previous miscarriages, the implantation will decrease even though you transfer the euploid-tested embryo.

That's the data sitting there. But on the other hand, by deselecting the uneuploid embryos, you may decrease some portion of miscarriages occurring due to the uneuploid itself. So, actually, when you look at the survey among our clinicians, I mean the IVF world, published in 2018, let's say six years ago, most of the data I quoted here published following 2018, they asked the clinicians, how you are acting for RPL patients? Do you recommend PGT-A? More than 80% are recommending PGT-A, actually.

But, I mean, I think if you sit in front of a patient who had lost six times, it might be that she's losing euploid. But if it's such a mental load, and she has enough blastocysts to actually do the whole PGT-A, fine, because then you can reduce for that patient the risk of the uneuploid, but you're never going to take away the underlying euploid. And that's what complicates everything we do here.

You can easily have a maternal factor, and then still lose uneuploid. Yeah. The only other comment I wanted to make, and you alluded to this quite nicely in the paper, I thought, was decreased ovarian reserve patients.

We all know that recurrent pregnancy loss that's otherwise unexplained, those patients have a higher incidence of DOR. And then it's a catch-22, because if your AMH is 0.2, the likelihood you're going to get a blastocyst is not, to biopsy, so low. So some of the patients aren't even going to be candidates at all.

But the psychology itself is also important while counseling the patients. As Johnny mentioned, I mean, the psychology itself. Because they could not, I mean, handle with the next miscarriages.

They want to do everything to reduce the miscarriages. This kind of stress for the clinicians while counseling those patients. Also, that's why maybe our colleagues responded that they recommend PGT-A.

Actually, the first study published by Dr. Munne in 2012, it's comparing the hysterical group and doing PGT-A for cleavage biopsy and also blastocyst biopsy, and showing that they are the same with non-RPF patients when compared with the SART data, as I remember. I would like to emphasize that, to me, they look like infertile patients. Basically, they have the same aneuploidy rate as infertile patients, and they have lower implantation rates if you don't do PGT-A.

Meaning that there is a lot of aneuploidy and fail, and a lot of losses that are not detected before clinical recognition. To me, basically, they are subfertile. Therefore, at a certain age, I would recommend PGT-A.

Would you like to comment on the mosaic embryo transfer for RPL patients? I mean, because you published extensive data on that. That's another long subject. Right now, the consensus, I think, in PGT-A is that if you have a low rate mosaic, they basically implant equally well as euploid embryos.

Also, abnormal cells, if you have a mixture of normal and abnormal, usually the normal ones tend to divide faster and then take over, basically. So you have to have a high load of abnormal cells to affect results. Then you'll have more miscarriages and implant less.

Also, some of those high mosaic embryos could be really misdiagnosed and they were truly aneuploid. So basically, right now, we would recommend classifying mosaic embryos just as high-rate mosaic embryos, and the low ones, you can transfer them. Recent data published in Fertility Test in 2021 actually made a subcategory for those patients.

The risk of miscarriage is following the transfer. As far as I remember, on that paper, you suggest the segmental mosaicism is doing the same with the euploid. But all of the low mosaics with the increasing number of chromosomal abnormalities could reach the 25% miscarriage rates.

If I am counseling, I am using that data with my patients that it may increase the miscarriage again. The difference was that in the early studies, all the data was retrospective, so you didn't have anything else to transfer. So you transfer a mosaic embryo, and then they basically miscarry less, they miscarry more, they have lower implantation.

But it could be also because those embryos were not as good as the other ones. They were morphologically worse than the other ones. In prospective studies now, they've seen that basically below 50% of normal cells they implant equally well.

Thank you. We have a question, Baris. First of all, thanks to FNS for holding the journal club here, and to the participants.

And if I'm allowed, I just want to make a comment. The studies are not of great quality. But it is what we have to live with for the moment, and we see patients on a daily basis, so we have to take a decision or give a recommendation.

So when we ordered this paper, the idea was to understand, not to be on one side or the other side of the debate. And once you write a paper, you have to stick to the numbers. You can't speculate that much, but I just want to comment on one of the earlier questions.

After going through all these papers, my impression is, actually, even though we can't state it that clearly in the paper, is I do think recurrent pregnancy loss patients are very likely to have a higher unemployed rate. So the two studies, as we mentioned in the discussion, that suggest similar unemployed rates. One, in the RPL arm, the patients are significantly older, and with any sort of statistical analysis, it's difficult to adjust for such a strong confounder.

And despite, I think, a three-year age gap, the RPL patients have a 30% higher unemployed rate. I mean, three years probably wouldn't make that much of a difference. And the other study involves people with multiple cycles, not proper adjustment.

So, in my opinion, among the available studies, the better ones suggest higher unemployed rates. So now that brings us to the other assumption, is we can't think of PGT-A without IVF. I mean, I know Santi worked on it, like doing PGT-A in spontaneous conceptions, but still, I think one potential benefit is, particularly for patients who are getting older, and I think Dr. Uman would agree as well, these patients, at some point, our feeling is before they really age much, start experiencing infertility as well.

So there might be some common reason. Anyways, by doing IVF and PGT-A, they are exposed to additional oocytes. Now, without stimulation, they would have never ovulated, they would have never tried, so increases exposure.

And then, yes, unemployment, especially at the resolution that we are diagnosing today, does not explain all the pregnancy losses, but we would all agree, among the diagnosed etiology, it is the most common. So by excluding it, you decrease, you would decrease some of the pregnancy losses. So as suggested by Ruth Lathi's paper a while ago, if the couple has the potential for a live birth, by going through this path, they would have it earlier, with probably less pregnancy losses in between.

So at the end, it will be an individual choice, but I think really everything hinges on the first question, and it's my impression that they are likely to have higher unemployment rates. But this is a question in line with this. Could we expect, so when our analysis becomes more detailed, resolutions become better, would we expect an improvement of the pregnancy losses, or a reduction of the pregnancy losses? Or in the end, do we not diagnose enough right now? Are we missing too many things? Yeah.

Barbara, I would like to actually, to your point, shift the attention away from the embryo back to the endometrium, because I would like to challenge the conclusion of the authors on the equal receptivity for both, right? And I would like to start by using as a base the data from Bill Kutteh, right, in which they looked into the products of conception. I look at this one-to-one ratio in terms of euploid loss versus uneuploid loss, right, approximately, just to make it simple. And if we assume that on the first pregnancy, a woman's got approximately, again, round figure, 10% risk of miscarrying.

That makes 5% risk of miscarrying a euploid fetus and a 5% risk of losing an uneuploid fetus. Now, if after three recurrent miscarriages, that risk increases to 40%, now it means her risk of losing a euploid is 20%, and an uneuploid is 20%. For me, both of them are increasing.

And there should be a reason that's not related, a confounder that's not related to the embryo. And to me, that's the endometrium. Now, even more complex, if I think that this proportionate increase from 5 to 20 on both ends is correlated with a disproportionate implantation rate between these two levels of embryos, a 50% conservatively implantation for the euploid and a less than 1%, say, 1% for the uneuploid, it simply tells me that this endometrial component is heterogeneous and not a single complex.

In other words, if I want to come back to the immunology of endometrium and try to simplify what investigators have been trying to brainstorm on, and we still have a long way to understand, then if we say we do have a permissive endometrium, so we're looking at TH1 profile, TH1 profile, a permissive endometrium that's enabling increasing the implantation, the 1%, the implantation of the uneuploid, then on the second phase, a poorly activated Th2, which is the anti-inflammatory immunotolerant that's resulting in a significant loss of the euploid, that hypothesis will explain everything to me. So I go back to the endometrium. In that question, actually, we did not mean that the endometrium is not important.

Actually, the question is a different aspect. It's only trying to check the hypothesis that it is overly, it is overly receptive. Doesn't mean that endometrium is not important.

When you look at the product of conception data, the question is actually, I mean, asking whether those endometrium is allowing to implant the uneuploid embryos more than those patients with non-RPF. But, I mean, not one study, coming from five different groups, around six study using karyotype, using microarray, much sensitive analysis, allowing to reduce the misdiagnosis due to the contamination from the mother, suggests that, I mean, the number of miscarriages did not increase, but we did not know what's going before implantation. So it's another story.

But when you look at the data from that side, following the miscarriages, and you check the product of conception, you can explain 60% of the case and the uneuploid miscarriage remains constant. That findings doesn't mean that endometrium itself is not important. Probably it's important, but we are looking only the uneuploid rate of the miscarriages to come up with conclusion for that question, actually.

This is an indirect analysis of the overly receptive endometrium. We believe that. I'm trying to make a point to the fact that when you say uneuploidy losses remains the same, we're talking about the ratio, but the actual, it is increased.

You know what I'm trying to say, right? It's not, right? It's a ratio between the uneuploid and the uneuploid, correct? Actually, you're right in terms, I mean, for that point of view, because as we discussed, the number of miscarriages itself could affect the endometrium as a proportion of, I mean, as a proportion. Actually, that study not look at only the proportion, but also did not allow to make us the analysis for this microarray one for the number of miscarriages itself. For that diagram actually produced from the karyotype analysis, maybe we need a new one to make, I mean, the comparison based on your comment, whether using microarray would provide the same ratio for us.

Actually, this is the missing point. Thank you. I would just like to comment.

So I think that when we talk about record pregnancy loss, it would be highly unlikely to believe that every time is the same cause. So a cause that is persistent is highly unlikely, believing that every time that woman will miscarry will be for the same cause, because in that case, we'll probably identify that cause and treat it. Now, with respect to the study, all studies have limitations, and those limitations have been well documented in the paper, and I think that this is as good as it gets right now.

Now, PGT-A itself is not an ideal tool. It has flaws, and although in theory on paper would be very nice to believe that if the cause is genetic, by doing PGT-A, you're going to select out those embryos who are incorrect, and therefore, by definition, logically, you'll say, well, miscarriage should decrease. But even miscarriages in PGT-A platforms vary, so they're not all the same across the board.

Not all platforms report the same miscarriage rate, but even then, miscarriage rates after PGT-A are lower than when you don't do PGT-A. I repeat, provided that PGT-A tool is performed correctly, because this is the problem. But I think that provided what we had today as information, I think Sez can actually squeeze the most out of those data, and I truly believe myself, I don't know the others, that I do not believe that it's a persistent cause of recurrent pregnancy loss whatsoever.

It could be a month, a genetical problem, next time will be an obstetrical problem, and the other one will be, let's say, an endometrial problem. But the question I have for you, do you really believe we can identify these pathologies each time, or it's just going to be going ahead and hope for the best? What's your take on this? For me. You will be the last one.

Ladies first. No, I'm just thinking that what we are really missing here is the history. Would we see some patterns if we knew what the chromosome status and what other factors that were involved in the first, the second, and the third loss, whatever? I mean, that is what we really miss here.

So we guess a lot about what has gone on before, and then we try to make conclusions on future, and I think that's really where it's getting interesting if we can add more knowledge, so it's not just that we say that's just nature, because nature has different paths, and what we have now is the opportunity to actually go down and explore the different paths, and hopefully that will give us a lot more information. For me? Yes. PGT-A is not only the solution for RPL.

Actually, we still, although we put enormous effort, also you are one of the pioneers for that effort, actually, to identify the reason for miscarriages over the last two decades. Still, we could not find a good proportion of reason compared to unemployed insiders. Let's mention about the lupus disease and also antiphospholipid antibodies.

It can explain only 7% to 10% of the little one, so it's hard to handle in the clinic practice. That's why the PGT-A itself, although it could not explain the reason, is not treating actually the main reason with infertile couples, just reducing the number of miscarriages due to the deselection of dynaploid embryos may help a group of patients, I do believe, based on the literature search. Thank you.

Other comments? No? Well, thank you all. Do you have questions? Last chance to have a question. Uman? Take mine.

So, thank you all of you. Also, beautiful paper. Congratulations.

Before I give you my take on that, I'm going to tell you a very short story. You know PGT-A is currently a debate, right? Pro and contra. Another debate which is ongoing is Fresh vs.

Frozen. You know it's ongoing, Fresh vs. Frozen, going right to the left, and it's changing.

There has been a paper from our colleagues in the Netherlands published in a good journal called Human Reproduction I think one and a half, two years ago. Beautifully conducted RCT. Beautifully conducted RCT.

And the result is frozen is significantly less good than fresh in a good prognosis population, right? I think less than 35, 36. Beautifully conducted RCT, and the conclusion is it is bad to freeze an embryo. It's unethical.

I don't know if you know that paper. So in less than 35, they have ongoing pregnancy rate of 8%. Good.

So it means it's a technical thing, right? Now the same is with PGT-A. Now I'm not an expert of PGT-A, but what I can tell you, based on the publication of Mina Popovic, if you look around the world at different providers, you could vary up to 20, 30% with your results, which means it's a significant technical thing. Now when you look, and I went to our genetic lab, I tried to look at the results, how the geneticians are telling you it's normal and abnormal.

It's very subjective, I would say. It's very subjective, and there are a lot of small segmental unemployed, which are being missed. So I think before we go into these studies, retrospective studies done in various centers and so on, first we need to identify what is the technicality behind it, and that's a shortcoming in our field.

You see? Is it done here, or is it done there? What is the experience? What is the quality of the genetic lab? What is the prevalence of mosaicism? You know the paper of Mina. The mosaicism rate is between 2 and 27%. Come on.

Between 2 and 27%, and it's affecting, obviously, also the outcome of these patients. Do you know what is the mosaicism in real life? It's less than 1%. So I think at the end, we should not neglect the technical part of it.

And another shortcoming that we have, and this is something that needs to be addressed, is that someone is a good endocrinologist. Someone is a good genetician. Someone is a good embryologist.

But we fail to have a holistic approach, and I think this is something which we need to work on all together. Thank you very much. I think I would like us to have a take-home message right out of this.

Go for it. And I think we might all agree that PGT-A is not the answer for unexplained recurrent pregnancy losses because it does not address the underlying pathophysiology. It could be a useful tool considering if we take into account, if we sort out the technical part and until further high-quality studies are available in women with high aneuploidy, that's women of advanced age, and with sufficient embryos that would be available for biopsy, that is with a very good ovarian reserve.

Would you agree on that until further studies are available? Not entirely. Not entirely. Please comment.

I truly believe that if you want to help those patients not to drop out, PGT-A, provided it's performed correctly, can help you. But you said until. So you have to... I mean, all those articles that were used in the analysis were retrospective trials.

So this database and the future studies are performed by our day-to-day practice. And although, as I mentioned, I don't believe PGT-A to be an ideal tool, and I truly believe there are very technical issues all over the world, I truly believe that for those who have a genetical issue, it is the answer to... not to increase pregnancies, because PGT-A cannot increase the pregnancies. That does not improve the embryos.

But at least by deselecting those who are incorrect, this patient will have less emotional damage and stress. That's my take on it. Thank you.

Yes? Yes, since we're in conclusion, so I would like to emphasize that, to me, they seem super-fat population, because they have the same aneuploidy rate than infertile patients, and they have a significant study twice more losses before implantation, so before clinical pregnancy. So, basically, they behave like infertile patients. Therefore, at a certain age, I think it's recommended to do PGT.

I think that it's extremely good to take away the aneuploidy, because that makes us much better in identifying the other causes, and I think that is really where this can take us. At the same time, I also want to make the point, especially among IVF people, that the majority of recurrent pregnancy loss patients are not after fertility. It's a minor group, and that adds to the complexity.

Actually, let's not forget the group has changed, because before it was more than three pregnancy losses, now it's more than two, so maybe in the future it will actually decrease even more. Euploidy and aneuploidy. So, I would like to thank you all for participating.

This will be recorded and will be posted on the site of Fertility and Sterility, and I hope you enjoy your day and wish to see you all tomorrow. Have a great night.