Welcome to Fertility and Sterility On Air, the podcast where you can stay current on the latest global research in the field of reproductive medicine. This podcast brings you an overview of this month's journal, in-depth discussions with authors and other special features. FNS On Air is brought to you by the Fertility and Sterility family of journals, in conjunction with the American Society for Reproductive Medicine, and is hosted by Dr. Kurt Barnhart, Editor-in-Chief, Dr. Eve Feinberg, Editorial Editor, Dr. Micah Hill, Media Editor, Dr. Pietro Bortoletto, Interactive Associate-in-Chief, and Associate Editor, Dr. Kate Devine.
Welcome to another episode of Fertility and Sterility On Air. I'm Micah Hill, the Media Editor. It's great to be back.
We're joined today by most of the team. Good morning, Kate. It's good to see you.
Great to see you too, and so excited to have you back, Micah. Thank you. Good morning, Eve.
Good to see you. Good morning, and I echo Kate's sentiments. It's great to see you.
And our fearless leader, Kurt Barnhart, Editor-in-Chief. How are you this morning, sir? I am well, Micah, and while I do see you, I'm glad everyone can listen to you and hear you as well. Thank you.
It's great to be back. We've got some great articles. I'm excited for my favorite morning of the month, as I learned from all of you.
So, let's dive right in. So, Views and Reviews this month. Editorial Editor, Michael Eisenberg, has just a great series of articles on immunology and male reproduction.
This reviews the testicular blood system barrier. It goes into anti-sperm antibodies, seminal fluid, cytokines. Especially if you're a female specialist like myself, I think this is a great review on the most up-to-date evidence behind male fertility as it relates to the immune system.
We also have a wonderful inkling by Editorial Editor, Anuja Dokras, don't let the hype outrun the evidence. Why PGTP shouldn't be rushed into clinics. I'm just going to actually read a couple of her sentences because they're so great.
She highlights that the ASRM's recent ethics committee does not recommend routine use of PGTP outside of research protocols. She says, in reproductive medicine, we've embraced innovation and like genetic applications in our practice, PGTP may one day find a carefully defined ethical place. Today, however, it risks overselling modest population level statistics as individualized certainty.
It could exacerbate inequities and undermine public trust in reproductive health. Our field does not need IVF add-ons that fail to treat the causes of infertility or meaningfully improve patient outcomes. Eve, I know you wrote a great fertile battle on this exact topic.
So, before we jump into the articles, just curious if anyone has any comments on the use of PGTP in our field. My view of it is that not a lot of clinics have adopted this, but there are some pretty prominent REI's with very large social media presence who are definitely embracing this. I'm just curious what the three of you think about PGTP.
I think the hardest thing to know is we won't actually be able to see the data for 30, 40 years. So, well beyond the scope of my intended practice. And so, I think it probably is not going to pan out for most traits.
I do think perhaps there may be some benefit in risk reduction for medical diseases like diabetes or schizophrenia, but I think that I agree the hype is far greater than the data shows. Yeah, I think the same as Eve in that, you know, we have to wait. On the other hand, you know, our patients are demanding this.
So, I think that while it's easy to give in to patient demand, we need to be as Eve would say, the physicians, not the REI providers, the REI physicians and interpret the lack of evidence that is there and counsel patients about the risk of pleiotropy. And until we have evidence of safety, I think we really need to exercise quite a bit of caution. So, I love this paper by Dr. Dokris.
And as usual, she has a lot of astute comments in there. I'll try to summarize it more philosophically. My worry about our field is we're changing from reproductive medicine to basically a dealership of what you want to buy.
And I think that we should be more on the medicine and use medicine when it's appropriate and use it when it's evidence-based. This is an add-on that some people are going to use and some people are going to buy. I can't change that away from a free society, but we shouldn't be hyping it nor should we be selling it.
And I mean selling it, like as opposed, you know, adding it on. Well, well said. I did not know that Anuja was actually part of the team that developed trophectoderm biopsy at Oxford University back in the 90s.
So, I learned some interesting things from this inkling. As always, she wrote with great clarity and insight. Kurt, you have the seminal contribution, Embryo Mosaicism, something we talk about a lot.
What did we learn this month? Yeah, this is a nice paper. I was happy to highlight it as a seminal contribution, mostly because it adds really good information. The idea that we're transferring mosaic embryos now is not necessarily novel, but this gives us a nice comprehensive picture.
So, the title is Impact of Different Types of Embryo Mosaicism and Pregnancy Outcomes by a group of authors in China, the Republic of China, in a couple of different laboratories and assays there. So, the great idea about highlighting a large article from China is that I'm very, very impressed with the number of patients that they have, and therefore the precision of the data. I'll just say up front, some of the difficulty is how translatable is it to our own patients, but I don't think the patient population is different in terms of like who has a mosaic embryo and the outcomes, but we still are going to have to have a conversation about, you know, what is their platform and how are they using PGTA.
Let's talk a little bit about it in real summary. This is a retrospective study comparing mosaic embryos, both the outcome, meaning do you get pregnant or not, as well as some of the childhood outcomes, versus euploid embryos transferred, and we'll get to how they selected those. So, it's relatively large, 435 mosaic embryos compared to 868 euploid embryo transfers.
It does a good job of balancing them. It uses GEA modeling to help control for the possibility that there might be more embryos in one cycle, and it also uses propensity score matching to try to get an idea to match these two populations, because already we know that the patients that only have mosaic embryos, in a way, are very different from patients that might have the presence of euploid embryos. So, the overall finding is that mosaic embryos have worse outcomes, and by outcomes they mean pregnancy rates.
So, it's a decreasing ongoing pregnancy rate in live birth. It's an increase in first trimester loss overall, and I don't think that's a surprise, but what's nice about the paper is they get a little bit more detailed. They look at segmental mosaic embryos and the outcomes for the segmental mosaic embryos are pretty similar to that of euploid embryos, whereas the chromosomal mosaic embryos have a worse outcome with, for example, an odds ratio of around 0.6, so a 40% decrease in live birth rate with that.
The complex mosaicisms, which are relatively few, were also worse outcomes. They also went into more detail. The driver of this is actually that it's not only just chromosome mosaicism, it's what type of chromosome mosaicism.
So, trisomy drives this a lot more than monosomy. I'm not sure we can take these numbers and say that they are absolutely precision, but if you transfer a chromosomal mosaic embryo that's trisomy, your odds ratio is around 0.3 and your miscarriage rate is around six times higher, whereas a monosomy is, they quote-unquote, say, similar to that of euploidy. So, the bottom line is not all embryos are equal, and it's really that the segmental and monosomal mosaics seem to be a better prognostic ability than the trisomy and high-level mosaicisms.
So, that's an overview of the paper. We can go into a little more detail. What do you think is the most important part? I think we should start with maybe the definitions, because not everybody knows the definitions.
So, mosaic embryos display two major chromosomal anomaly types. There's, again, chromosomal mosaicism, the typical trisomy-monosomy I talked about, and segmental mosaicism. So, chromosomal mosaicism generally arises from meiotic segregation errors.
So, it's a problem in fertilization and development. It's nondisjunction. It's anaphase lag.
It's, you know, those kind of issues. So, therefore, you can gain or lose an entire chromosome, for lack of a better word, whereas segmental mosaicism, on the other hand, more commonly stems from the errors in repair during the growth of an embryo. So, repair of double-stranded DNA breaks, and that results in possibly duplication or deletion of genetic material.
So, right off the bat, they're different ideas. We think of chromosomal mosaicism as more age-related, whereas it's not so clear that segmental mosaicism is actually age-related or not. This is a nice paper that tells us these things, but we still can't get away from the discussion that they bring up in their paper, as well, in their discussion about what is this error here? What are we seeing on mosaicism? Is mosaicism truly a reflection of the embryo? Is it truly a difference in the trophactoderm versus the inner cell mass in that the cells are being sequestered in the trophactoderm? Is it got to do with the embryo fixing itself, or has it still got to do with the platform itself and the mathematical models of how we're counting when we see trisomy or monosomy are the right number? And that is not resolved in this paper.
So, that's what I meant about the generalizability about one center that uses one type. It did use next-generation sequencing, but, you know, what is their lab compared to the labs we use or the labs that you use? Because there is a lot of literature that even the call of mosaicism is very different based on lab. So, we're stuck with a great paper that quantitates that mosaicism perhaps isn't as bad as we think clinically, yet we still don't know what mosaicism is telling us.
And is it a function of the laboratory, the patient, or embryo development? So, I'd love to hear your guys' thoughts on this, because this is why I think it's a great paper, because it brings up this discussion. I don't think it's embryo development, just because we don't see mosaicism phenotypically or genotypically in live births. And so, I find it really hard to believe that all of these embryos are mosaic and they self-correct prior to chorionic phyllosampling, amniocentesis, prior to live birth.
And so, I personally think that it's the interpretation of copy number specific to NGS, and that as we refine our ability to do PGT, I think we're going to not see mosaicism. And so, I think that it's probably a misnomer that we're calling it mosaic rather than calling it intermediate copy number or something along those lines. But maybe I'm wrong.
Dawson listens to this. He'll certainly agree with you on that, Eve. I think the fact that it varies based from lab to lab and that as technologies evolve, the incidence or prevalence of mosaicism changes in and of itself suggests it's the platform rather than true biology.
I mean, don't you think if it was true biology, we would see it more in products of conception testing when we get an actual karyotype? We would see it on microarray when we do CVS or amnio? I just feel like it's a phenomenon that's limited to embryos, and biologically, I just don't believe that that's the case. So, just to be clear, when I'm saying it's the embryo, I don't mean that the embryo is fixing itself, that it's truly mosaic. I mean the idea of the intercell mass and what you're actually measuring with a trophectoderm, that that might be embryo biology, not necessarily reflecting.
So, you might be biopsying something that's inherently more complicated than the intercell mass, where cells are sequestered or cells are stepped out. So, it might truly be you're measuring a mosaic sample of the trophectoderm, but the trophectoderm might not be representative of the embryo. No, and I agree with that.
But when you do CVS, you're also sampling the placenta, which comes from the trophectoderm. And it's not to say that we don't see confined placental mosaicism, because we do, but the frequency of that is so much more rare than the frequency of mosaic embryos. And so, I just don't know what to think of it.
I think what would be interesting is we're seeing mosaic embryos and then we're doing confirmatory testing on the fetus, but that doesn't really say that the placenta wasn't mosaic. And so, I think that the ultimate test that we should be doing is evaluating the genetics of the placenta after birth and evaluating when we do a karyotype, we're looking at peripheral cells from that human, but we're still not measuring what we think we're measuring, which is the trophectoderm. And so, we keep saying like, these children are normal, everything's fine, the testing's wrong, but we're actually sampling two different things.
I totally agree with that. That's it from a complete pragmatic perspective. Of course, what matters is, is the baby healthy or not? Of course, if we were able to, you know, call the resources to do a massive study where we looked at every placenta from a mosaic embryo, I think that would be biologically fascinating.
But at the end of the day, we have to also decide as physicians, how do we report these results to our patients? How do we utilize the results? How do we counsel our patients? I am thrilled that we as a practice have finally triumphed in convincing the majority of our physicians that we no longer need to be reporting low mosaics from NGS. Because again, it's the clinical significance of these results that matters to our patients. And it's stressful.
It's stressful for patients. It's stressful for physicians to have to think for many months sometimes that they are potentially carrying a abnormal baby, because these results are reported as abnormal. And so, as the predominance of evidence has shown that low mosaics are extremely unlikely to result in an abnormal child, you know, I think that it no longer makes sense to be reporting these as such.
I mean, high mosaics are not likely to be an abnormal child. We've been transferring all mosaics in our practice with excellent results. And when I say excellent, you know, probably about 30% live birth rate as opposed to our usual 60 to 65% live birth rate.
But with normal babies and normal testing, and I think the next frontier is probably these segmental aneuploids as well, that right now we're not transferring, but I think the data on those are promising as well. Yeah, so that's a good summary to the paper. So, again, this is what I meant by it's not novel, but it adds some information.
So, I still, as a scientist and physician-scientist, still worry that the trifecta germ is really not always reflective of the embryo. And the whole process of PGTA has more limitations than we think in terms of what are we actually measuring and what's the answer. We can have a whole debate, and I hope you all attend ASRM this year, where we're going debate how PGTA was developed and what testing still needs to be done.
You know, is it really diagnostic of the embryo or is it really just prognostic of live birth? That said, this is telling us some important information. By the way, they talked about high-level mosaicisms as 50%, which is not what we do. But it does say that live birth rate is around 40% lower with a chromosomal mosaic, and it does also say things like that the segmental mosaicisms are less worrisome.
And then the other take-home message, do with it as you please, it seems to be that a trisomy is more worrisome than a monosomy. Biologically, I'm not sure I can figure that out, but there is trisomy explanation. And then the last thing I'll leave you with, it's completely underpowered, but it's reassuring, they also look at maternal complications, which every study should look at maternal complications and child complications.
And even though they don't have everybody and the numbers are small, there doesn't seem to be any difference in things like congenital anomaly or gestational diabetes or growth and things like that. So it's adding literature, but this is still a debate worth having, which is, again, why I'm happy to do as a seminal contribution and why we talk about it on this podcast. That's a great summary.
Eve, we're going to move to you, but we're going to stick with the theme of mosaicism and we're going to talk about ejaculatory abstinence. What does that have to do with mosaicism? Nothing. Next article.
No, I'm just kidding. So the title of this article is Evaluating the Relationship Between Ejaculatory Abstinence and the Incidence of Embryomosaicism. And this is first author Sean Kripalani with senior author Alan Kopperman and our very own Kate Devine as one of the middle authors.
This was a multi-center retrospective cohort study evaluating ejaculatory abstinence and embryo mosaicism and IVF cycles with PGTA. Study was conducted over a three and a half year period between December 2019 and August of 2022. And it was conducted across a national network of fertility clinics.
So included were a little bit over 2,000 IVF ICSI cycles using fresh ejaculated sperm and autologous oocytes. And cycles were excluded if they had known male factor infertility, donor or frozen gametes, testes sperm, prior chemotherapy, or any known testicular pathology. Embryoploidy was assessed using next generation sequencing and PGTA for PGTA.
And the ejaculatory interval was self-reported and grouped into the following groups, zero to one day, two days, three days, four days, which was the reference group, five days, and then they lumped together six to 10 days. The primary outcome was the embryo mosaicism rate. So number of mosaic embryos over total number of biopsy embryos.
And then secondary outcomes were euploid rate, aneuploid rate, sperm concentration, sperm motility, and standard IVF cycle outcomes. The models were adjusted for male age, egg age, BMI, AMH, peak estradiol, PGT lab, year of treatment, and GEE was performed to account for multiple cycles per patient. And so what did they find? Not surprisingly, sperm concentration increased with longer ejaculatory abstinence intervals.
Motility did not differ significantly across all groups. And then embryo mosaicism, which is the primary outcome of the study, the rates were low and they were similar across all intervals. The adjusted analyses showed no association between abstinence duration and mosaic embryo risk.
And there were some small statistical differences in euploid and aneuploidy rates in some groups, but not a consistent pattern that I would report back. And really, there was no consistent dose response or biologically plausible trend which was identified. And so, you know, basically we can say that the ejaculatory abstinence between one and 10 days is not associated with embryo mosaicism.
And standard IVF outcomes, things like fertilization, blastulation rates, were also unaffected by abstinence interval. And while there were some of these changes in sperm concentration, it didn't translate to anything meaningful in terms of chromosomal integrity. And so I think, you know, what we can say is timing can be guided really by patient convenience rather than concern for mosaicism risk.
And so, you know, I think overall it asks and answers an interesting question. And I'm curious because biologically, I wouldn't have thought when I looked at the title of the paper. I was like, hmm, why would this be? Like, why would we think that ejaculatory abstinence would lead to higher rates of mosaicism? And so I think it's just one more thing we can say.
Yep, we've looked at it. Doesn't seem to impact rates of mosaicism and stick with current practices. So I'm curious, Kate, from your perspective as an author on this paper, some of the behind-the-scenes work on this.
Yeah, thanks, Eva. I do think that this question of how duration of abstinence impacts clinical outcomes in both low and high-tech treatment is an important one. I do think that some of the secondary outcomes in this paper to me were more of the reassurance that I was looking for and would have wanted part of me to evaluate.
I do also think that the, you know, looking at all comers is very different from looking at a population of patients who have had poor outcomes in previously, specifically low fertilization, low blastulation, low rates of euploidy among prior PGT cycles. I know our urologists have really slowly become true believers in a shorter duration of abstinence and its impact on some of these intermediate laboratory outcomes. And I will say though, to be clear, and that might be really important in a population of males with male factor infertility, which were excluded from this.
And so I don't know that we can generalize ejaculatory abstinence interval for that population that's had poor outcomes. So I think for the general population, it probably doesn't matter, and it may be more specific to those who have more severe male factors. A hundred percent.
A hundred percent. So again, I think it's a relatively large sample because it was a generalized sample. And so provide some reassurance about a question that maybe some of us were wondering about, but maybe some other questions that have a little bit higher clinical relevance that we could dig into in the future.
Like that it's a null study. I know people have this impression that null studies are less likely to get published. I actually don't think that's true.
I certainly don't think that's for fertility and sterility. It's reassuring. And Eve, I like that you made two comments, that there was no consistent pattern in the data and that there was no dose response in the data.
So I appreciate that the authors sort of dove deeper into it, sliced up the data in multiple ways, and sort of no matter how you sliced it, it was overall reassuring, which I think is of value to our clinicians and our patients. Yeah. And I will say, I feel like I read so many papers where there are these little differences that people are highlighting and getting lost in the forest, where when you look back and you really look at it from a big picture, that's noise and it's not moving the needle.
But I think that there's a tendency in some papers to really stress the positive findings in the setting of a null paper. And so what I really liked about it was the fact that it was a null finding and it was, even though there was some signal, it didn't interfere with the overall view of the paper. I thought that was really well written.
Yeah, I'll highlight that with you, Eve, that really what makes a paper acceptable to FNS is that you can clearly see a hypothesis and a rationale for that hypothesis. Now, again, I wouldn't have thought of that as a hypothesis, but it's intriguing to see the rationale behind it. And then they had a clear primary outcome and they very effectively and meticulously demonstrated that it was a null finding.
That's good science. You know, to highlight some of the tertiary outcomes that might have been statistically significant due to chance is what many people try to do. And those are the kind of papers I don't want to see in fertility and sterility.
So the appropriate aspect here is, look, the hypothesis made, it hasn't been demonstrated to be true. If you really think, for example, that it might work in severe male factor, then that's a new study for you. So I'm really pleased, again, that good science gets in the journal.
Well said, and a perfect transition. I was actually going to highlight this study. Both of mine had very nice hypotheses stated.
And I do think for those fellows and authors listening, make sure you state your hypothesis. Sometimes that'll tell you that maybe the study shouldn't be being done in the first place, or it helps you refine actually how you're answering the question when you define your hypothesis. So this is the next paper we're sticking to.
Andrology is looking at vitrified and slow frozen donor sperm and IVF. These are authors out of Spain. First author, Cole.
Senior author, Pregio. And friend of the show, Nikos Palizos. Great group looking at whether vitrified sperm versus slow freeze donor sperm makes a difference.
And there's some biologic plausibility here. We know this, I think, from embryos pretty well that slow freezing can cause intracellular ice crystal formation and damaging that organism. Certainly, you would hypothesize that that risk would be greater if we're talking about a single cell, like a sperm or an egg.
There's also some evidence that slow freezing might increase intracellular or cytoplasmic damage by things like reactive oxygen species formation. So they very clearly state their hypothesis that vitrified donor sperm could lead to improved embryologic and clinical outcomes compared to slow freeze. Now of note, this group uses three different sperm banks in Spain that use these various techniques.
And so this is a limitation of the study that perhaps this is a reflection of the quality of the procedures within those three different banks rather than the actual procedure itself. But still, I think this is a very novel study that hasn't been looked at before. So they looked at fertilization, usable blastocysts, and clinical pregnancy as their primary outcomes.
Now of note, there are some people that used ICSI and some people that use conventional IVF. With this donor sperm, it was about 2 to 1 ICSI compared to conventional. And they had 600 IVF cycles in about 460 patients.
Again, about 2 to 1 used vitrified versus conventional. They had some very nice methods looking at fixed and random effects, isolating out patients since they had patients that did contribute multiple cycles. Of note, they did include in their multivariate logistic regression the transfer of a good quality embryo.
And in my mind, that's sort of downstream from vitrification versus slow freeze. If in theory, it affects things like intracellular damage and reactive oxygen species, that could affect your ability to get to a good quality embryo. So that might actually be a mediator in the causal pathway, if you think about your DAG diagram.
So it's a minor nitpicky thing, but I don't know that I would have included that in my adjustment. But overall, what did they find? So overall, fertilization, their primary outcome was 77 versus 76 percent. Not different.
So reassuring that both techniques had good quality outcomes from a fertilization standpoint. When you broke it down, though, with ICSI, it remained the same. No difference between the two, 77 versus 80 percent.
But when you looked at conventional insemination, there was a difference, 76 percent with vitrification, 66 percent with conventional. So in other words, this suggested with their sub-analysis that maybe if you're doing conventional insemination, you're better off with vitrified sperm than slow-free sperm. Their other primary outcomes, blastocyst formation rate, clinical pregnancy, were not different.
Of note, what I mentioned that I don't know that I would have adjusted for embryo quality. Embryo quality was 10 percent higher of having a good quality embryo if you used vitrification, 70 percent versus 60 percent. Again, I think that's in the causal pathway, so they might actually be minimizing a potential effect by adjusting for that.
So overall, they conclude that both techniques seem to work well, but maybe if you're going to use conventional insemination, vitrified sperm is better. Interestingly enough, I Googled AI this, and AI says pretty definitively, vitrified sperm is better if it's donor, and they cite three studies. Actually, it's this study cited three different times on three different platforms that you can get FNS articles.
So AI is convinced that this study in three different citations has proven that vitrified sperm is superior, even though it was only in one outcome in one subgroup. So I think just a warning note to us all, as we try to integrate AI and learning information quickly, that sometimes it can feed us biased information. So I open it up to the group.
Thoughts? Really? AI can be biased, Micah? Is that what you're saying? I always remember you telling me like a decade ago or a long time ago, Kurt, that AI could detect wolves versus certain types of dogs, but then they figured out it was actually seeing snow in the background, and that was telling them that it was a wolf and not a dog that looked like a wolf. I like this study, even though I think it's a question that for most U.S. sperm banks, I think, doesn't come up too much. We're not seeing a lot of, in my practice anyway, slow frozen sperm.
As you very nicely laid out, it's a hypothesis-driven question and well-answered, and again, a null finding. So I guess we have a little bit of a theme, but certainly clinically relevant, particularly for those practitioners that have a choice between cryopreserved and vitrified sperm, that they can reassure their patients, particularly if there are cost differences, et cetera. Yeah, I had a fellow years ago that said when we were doing a lot of the reproductive medicine unit studies, and some of them were reading very seminal papers, and he says, why are you all studying this and telling me what not to do rather than what I should be doing? But that seems to be a theme in our research, is that people come up with a treatment, and we have to spend a lot of time showing that one is better than the other, or something we came up with without evidence was actually wrong.
So maybe that's the theme of good hypothesis generation, and we can end up doing the right thing. Well, and there are infinitely more things not to do than things to do. So true.
All right, Kate, we're moving on to you next. This is right in your wheelhouse. I think you are the queen of talking about luteal phase and natural cycle versus modified natural cycle.
So I was excited to see this meta-analysis and to hear specifically your thoughts on this. So teach us what we should learn from this article. Yeah, thanks, Micah.
This is a really well-done, in my opinion, systematic review and meta-analysis by Vanitas et al., colleagues from Australia and also collaborating with colleagues in Greece in an attempt to answer what is becoming an increasingly important question of to trigger or not to trigger in frozen embryo transfer cycles where a corpus luteum is present. So just to take a step back, this is a question, as I said, that's coming up increasingly more often because we are doing so many more frozen embryo transfers over the last one to two decades. And because of the data suggesting that modified natural or natural cycles may be more both patient-friendly, but also potentially safer.
And so specifically, as we've spoken about on this podcast many times, there is the thought that artificial cycles where the corpus luteum is absent may be more associated with hypertensive disorders of pregnancy. So the other issue, though, is that when clinics are hoping to administer a cycle with a corpus luteum for their patients undergoing frozen embryo transfer, there is a scheduling headache. So true natural cycle would mean that you are watching the follicle grow, waiting for that spontaneous LH surge, and that's a lot harder to plan, and it's a lot more monitoring on average.
So modified natural cycle, just to kind of set out definitions at the outset, means that there's an HCG trigger of a spontaneously developing follicle, and that enables some limited scheduling flexibility. Obviously, not as much as with the program cycle, but still helpful to patients in clinics potentially. So this was, again, a systematic review and meta-analysis of randomized controlled trials only, and that's important.
They did a comprehensive literature review through October 2024 and ended up with six RCTs that totaled 1,708 patients, again, published through 2024. So the range of data were amassed between 2010 and 2024. They did do a rigorous quality assessment of the included studies using the Cochrane ROB2 tool to evaluate risk of bias, the GRADE tool for the overall quality of evidence, and the TRACT checklist for trustworthiness, which is a newer layer of scrutiny for meta-analyses.
They did find that three of the six RCTs had a high risk of bias, but they were all included based on a favorable TRACT assessment. And appropriately, they did a sensitivity analysis where they excluded these high risk of bias studies. So in terms of results, again, reassuring not to, you know, bury the punchline here, but this is another negative study.
So there was the primary outcome of live birth per randomized patient, and they found no difference. So, you know, relative risk was 0.93 with a 95% confidence interval of 0.74 to 1.17. And the I-squared was 0%, meaning pretty consistent results across studies. And then they did take out the high risk of bias studies for the primary outcome that they found two were high risk of bias, and there was still no difference among these.
They looked also at clinical pregnancy, ongoing pregnancy, cycle cancellation, and miscarriage rates, and again, no difference in any of these outcomes. So across the board, triggering did not appear to negatively impact the clinical outcomes that they were assessing. So bottom line here is that, and frankly, not surprising to me, but reassuring is that to trigger your patients who are doing a natural cycle of frozen embryo transfer, hence to choose a modified natural rather than a true natural cycle protocol is appropriate.
You know, a couple of caveats is that, you know, in the four studies that contributed to the primary outcome after removal of the two studies with high risk of bias, there were 1,280 women, which is, you know, a lot of patients, but it's not a huge number when we're talking about a meta-analysis. And, you know, you could imagine that with that type of a sample, while they didn't find any statistically significant difference here, it's not really powered to rule out small differences that could still be clinically meaningful. And then kind of taking a step back from all of this and kind of what my criticism, if any, of this study, which is very well done, is, is this really kind of the right question at this point in time? So I don't know, it's not something I personally have been super worried about is does a trigger hurt? And, you know, again, they looked at, there was a prior Cochrane review that found the exact same thing as this, and that was two RCTs ago.
So, you know, how much is this really adding? I think kind of the question that's more burning for me is this really important question as is there actually a benefit to the corpus luteum at all? You know, I did a deep dive in a talk I gave at PCRS recently on this, and the preponderance of evidence, to my mind, still don't really show a clear lack of birth benefit. But there does seem to be an emerging signal in terms of patient safety. And so I would refer folks to a really great paper in the British Medical Journal from 2026, Damon Way et al., which is a huge sample and did suggest a lower risk of gestational hypertensive disorders of pregnancy.
And I anxiously await Val Baker's study that many of us participated in, the NATPRO study, which is actually a little bit of a smaller study than the Way paper, but kind of more in keeping with contemporary U.S. practice. And I think we'll have some really important clinical impact for our field and the way we practice in the U.S. So, interested in everybody's thoughts here on this paper and whether you think we can kind of put the nail in the coffin of any real benefit for true natural cycles, which are, of course, a lot more arduous? Yeah. I mean, I agree with you.
Two RCTs ago. So, like, I think that we've moved towards modified natural almost exclusively just because the convenience for the lab and being able to better plan the number of transfers that we're doing for verification and safety purposes. I think it's very chaotic to do natural cycles, true natural cycles, because you just have no control over the timing and the numbers that you have.
And so, I think that the data are really reassuring that there's no difference between the two. And I think the bigger question, as you stated, is what is the benefit of a corpus luteum? And yes, there's a lot of signals, but I think that we are all anxiously awaiting NATPRO to really look at those outcomes, live birth outcomes, and not from a success standpoint, but from a preeclampsia and hypertension and pregnancy standpoint. Is modified natural your standard protocol, or is it still a replacement cycle just if they ask for some form of natural at Northwestern? It's very individualized.
We're doing, I think, about 50-50. I think what intrigued me about this article, and again, the reason I advocated for it in the journal, was, again, let's quickly find out if there's a what not to do, right? We like the idea of a natural cycle. Of course, everything, getting back to natural, has this intuitiveness.
People have been reproducing for a long time without ART, so a natural cycle has lots of benefits from that aspect. But very quickly, we have a decision here, our convenience, lab convenience, practice convenience versus natural. And if our convenience really is detrimental, we need to know that early and soon.
I'm glad that RCTs have demonstrated that, and then I'm glad that we have the ability to put that in the journal to reassure people that what we're doing was not a bad choice. That's the rationale for it. But you're right, it doesn't answer all the questions, and there's a lot of questions left, which is, again, the overall safety.
And I firmly believe that the differences here are going to be small, but really important in a public health perspective because so many people are using it, that we really do need, you know, more RCTs on all of these things, rather than just a feeling that we've already studied data and we're done. Ada's a co-investigator on NAPRO. Any guess as to when that study might be out? When will we have an idea of what that data looks like? I think that the data will be ready for publication early in the summer.
When will the actual, when will we see the publication? I'd probably guess late summer, early fall, but it's soon. I mean, we've been waiting for seven years or something. So, you know, we're like 98% of the way there.
Fantastic. I know we are all waiting with bated breath to see what that is. All right, we have one more article.
We're moving into gynecology and surgery. Actually, I'd asked Pietro to present this one. I was curious on his thoughts, but I'm going to do my best to put my surgeon's cap on.
So, this is looking at pre-treatment for laparoscopic myomectomies with Lupron versus Rulagolix, the Mylicar study. So, this is out of a group of authors from Japan. This is a randomized clinical trial at multiple centers.
They had about 30, sorry, 67 patients randomized to those two arms. They were treated for three months, so 12 weeks of treatment with either daily Rulagolix or three separate Lupron injections, monthly injections. And their primary outcome was looking at a reduction in blood loss.
Now, interestingly, this was a non-inferiority study. We don't see a whole lot of non-inferiority studies. Typically, when we're talking about a non-inferiority study, we're talking about a drug that's maybe cheaper or maybe easier to use or maybe more patient friendly.
And that kind of raised my thought on this one a little bit because you would think that Lupron is probably a little bit cheaper than the oral daily antagonists. But this one is looking more at the side effects. And so, how quickly does your hormonal system recover with Lupron versus that? So, that's their argument of why they would do a non-inferiority study.
So, on average, they said that Lupron reduces blood loss by about 90 mLs in a myomectomy. And so, their non-inferiority margin was 50 mLs. And at first, I was kind of critical of that because with a small study, if your non-inferiority margin is more than half of your difference that you're going to expect, you're almost bound statistically to find that it's non-inferior.
Like it's going to be the outcome. But when we teach our fellows how to do non-inferiority studies, we generally tell them what's the minimum clinical difference that would maybe change your practice. And I do think 50 mLs of blood loss, if you're going to suppress someone for three months, might be different.
So, I'm just curious what you guys think as far as is that a reasonable non-inferiority margin? They're arguing clinically it is, which I think is probably right. But Kurt, you're our resident statistical expert. What do you think of that as a non-inferiority margin? Yeah, I was intrigued by why this was a non-inferiority study as well.
Non-inferiority studies tend to require more people, and they're a little bit more complicated than an inferiority study. But the conclusion is different. So, you can really say, in this case, which I think is what they're trying to do, that it really doesn't matter clinically if you use the two, as opposed to trying to prove that one is actually better than the other.
So, in that sense, I agree non-inferiority makes sense. I guess we could argue where the 50 cc is the right margin. It sounds appropriate.
But, you know, I don't know whether 75 or 25 would have been better. Sure. It sounds like you had similar thoughts that I did.
So, they included patients who were over 20. They all had an MRI of their fibroids. They had to have fewer than five, and the fibroids had to be between 2 and 12 centimeters in size.
So, again, these women all had three months of downregulation with one of these two medicines. Interestingly enough, in Japan, you have to be, or you can be, certified to be an expert in doing laparoscopic myomectomies if you have a high enough volume. All of the surgeons did.
They also used vasopressin intraoperatively to help reduce blood loss as well. Again, their primary outcome was intraoperative blood loss, which they measured using cylinders and counting sponge counts and those sorts of things. So, ultimately, what did they find? Well, there was no difference.
Now, I wish they had done it based upon intent to treat. They did not. They did per protocol.
That always kind of bothers me. I think RCTs, especially when you're talking about a three-month treatment, you want to know, can patients actually do that? And so, excluding patients that couldn't do that for whatever reason, I would like to see the intent-to-treat analysis. But they did a per protocol and then a safety analysis based upon patients that actually got the correct treatment.
But the bottom line is that there was no difference in their outcomes. 72 cc's of blood loss versus 84 cc's. The non-inferiority margin, the Religolix group actually did a little bit better, but that non-inferiority margin was 28 or 32 if they adjusted for confounders.
So, it was less than the 50. Interestingly enough, the 72 versus 84 was statistically significant. That surprises me a little bit, given that they only had 30-something patients in each arm, and the difference is only 12 cc's.
But the p-value on that, they report, is statistically significant. So therefore, not only is Religolix non-inferior, it's also superior. So, you can find superiority in a non-inferiority trial, which is what they found.
They didn't state that, but that's what the data actually shows. Looking at side effects, not surprisingly, the antagonists, the Religolix, you rebound your estradiol quicker. So, if you look at estrogen levels, recovery after surgery, it recovers a little bit quicker.
Estrogens, cardioprotective, it's cholesterol protective, and Religolix actually rebounds its cholesterol quicker. So, these women end up with higher cholesterol, more likely, but it rebounds quicker. So, I think that's their argument for why you can do a non-inferiority study.
There's some patient benefits, although you could argue the converse. The Religolix is going to be probably much more expensive, depending upon if your cash pay and what your insurance will or will not cover. So, I love that we have a multi-center RCT.
It's interesting that we get to talk about non-inferiority. I don't generally treat patients for three months prior to a myomectomy unless I'm really worried about blood loss, and we're talking about blood loss here that, on average, was under 100 cc's. I will say they put their data in standard means and standard deviation, and the standard deviation was greater than the mean, which means it's really right skewed.
So, most patients are losing a little bit of blood loss. A few are losing a lot. They really should have said median and IQR.
The whole point of giving that data is to allow the reader to interpret in their mind what the spread of the data looks like. When one standard deviation gets you into gaining blood from a myomectomy, you know that's not possible. You can't gain blood from a myomectomy.
And so, I wish they had said it that way, just so we could understand that spread a little bit. But a really nice RCT. Glad to see gynecology, and surgery, and fertility, and sterility.
I have an off-topic question for you guys. We see a lot of these studies coming from other countries like Japan that are using rural ecologics. Why do you think it hasn't gained traction in the States? Why aren't the United States using these medications, and why aren't we using them more in our fertility practices? Do you have a feeling? For me, it's cost.
It's just so expensive, and if insurance isn't going to cover it, the out-of-pocket cost for these three months, a month of rural ecologics from my searching can be $3,000. So, if you're doing three months of that prior to surgery, that's $9,000 if it's out-of-pocket. And if the insurance is going to come back and say for, you know, 50cc blood loss difference, or in this case, 12cc blood loss difference, it's maybe not cost-effective, would be my guess.
I don't know. Eve, Kate, do you guys have an opinion on that? Yeah, I wholeheartedly agree. And I would actually ask the other question is, why are these other countries using it when the benefits are so minimal? I agree as well.
I would imagine they're less expensive there, but I don't know that. I also think, you know, while, Micah, you make the very astute point that you cannot gain blood from a myomectomy, you can't gain your own blood, right? So, you know, I think really what we care about is not the, again, the small but statistically significant differences in, again, these very low-volume blood losses, but what's the difference in the, as you say, catastrophic blood loss? Who needed a transfusion? As you say, these are skewed data. And so, I think I might be convinced it's worth $9,000 if there were a statistically significant reduction in things like transfusion or really, again, catastrophic blood loss.
Well said. And in this study, there were no transfusions in either arm. However, we don't know what those outliers look like because they didn't really tell us that with how they presented the data, but it was not enough in any of the patients to get a blood transfusion.
Wow, we covered a lot today. So, any final thoughts? So, last thought, Kurt and Eve, because, Kurt, obviously you're Editor-in-Chief. Eve, you were on the Publications Committee of ASRM and the Chair last year.
So, I think there were seven letters of concern this month. Can you just tell us the difference, Kurt, between a letter of concern and a retraction? Yeah, sure. So, let me remind folks that it's still very eye-opening that there's allegations that a lot of the literature, not just OB-GYN or fertility and sterility, but around the world, is not trustworthy and that some of it is skewed, some of it is biased, and some of it has actually never happened and is made up.
So, there's allegations that people put in that this paper might have problems, and it goes through a process, and ASRM clearly has been leading this process across the world, so to speak, in that we have actually a committee, a research integrity committee, that's staffed by lawyers and statisticians and epidemiologists, as well as reproductive endocrinologists, that look at the allegations and look at the paper and then come up with the determination. If you really think the study does not deserve to be in literature, is misleading, is wrong, then the article can be retracted. However, if you think that the allegation has merit, but the allegation of fraud can't be proven, or it's not bad enough to warrant retraction, then what you can do is put on a letter of concern, and what that says is there was an allegation, here's what it is, we couldn't get to the bottom of it, or we got partially got to the bottom of it, and you should take this finding very cautiously when you read this paper.
What really is important, this should absolutely be part of the process of doing a meta-analysis. Papers that have retracted should never be in a meta-analysis at all, and papers that have a letter of concern, at the very least, should be in a sensitivity analysis, only putting them in after your primary analysis is the trustworthy papers. The idea is that readers can identify and understand when you want to be careful in an interpretation of a paper.
Thank you to the Research Integrity Committee for their hard work. We're doing our due diligence to try to make the literature in FNS, not only today, but in the past, have as much integrity as possible. Yeah, thank you, Kurt.
That's very well said. Eve, do you have any other thoughts as the chair of that committee last year? Yeah, I mean, the only thing I will say is that it's an incredibly smart committee with some of the most talented people in our field who are not only making these judgment calls, but really diving into the data, obtaining the data, rerunning the statistical analyses on the data. And I think it's with a lot of gravity that retractions happen.
And when we couldn't quite nail it and say that it doesn't make sense, the next best thing is this expression of concern. And so, I think that it was an honor and a privilege to be part of that committee, but the real work is done by the shepherds for the individual cases who dive in and really just redo these analyses to the point where they're just really well done. And it's scary to me how much concern there has been that's been expressed.
And so, I think it's an evolving landscape. And my hope is that moving forward, we're going to see less and less of it, and that the criteria for publication, especially in FNS, have become more rigorous over time. And I think that methodologic editors are a really nice stopgap that Kurt has employed in this new iteration of the journal, so that hopefully we are going to catch these things prior to initial publication and not retroactively get complaints and investigate it.
But there is a really elegant process. There's a portal through which you submit a complaint. It has to be very specific.
You can't just say, I think this paper is fabricated. You have to give exact reasons why you suspect it, and then it goes to the committee who really does a ton of work in diving into that data. I have one naive question, actually, as someone who's just really appreciative of three of you have really spearheaded putting FNS at the leading edge of this type of work, which is just so important.
What is the standard for a letter of concern being published? Because obviously, we're getting a lot of them. Are there some that you as a committee just decide are completely spurious or vindictive? And what percentage of the submissions that you get would you say fall into legitimately concerning versus noise? That's a great question. And I actually don't have the data in front of me.
But the Publications Committee, along with Jessica Goldstein from ASRM and several others from the RIC have actually put together a manuscript where we've detailed the process that we've developed in creating the committee and the Research Integrity Committee. And we have the data at one point where we looked at the number of submissions and then the ultimate outcome of those submissions. And I will say there were a lot where it was investigated and they were found to be honest mistakes, typographical errors, mistakes in calculation.
And the other thing is we had to actually get the data in order to make an assessment. And so my message to all of the researchers out there are please hold on to your data. Don't discard them.
Some of these papers that were whistleblown were greater than 10 years old. And so a lot of these researchers did not have their data. And so if we didn't have the data to actually look at the data and see whether or not it was fabricated, you can't legitimately attract a paper if you're not actually diving into the data.
And so that's where some of the expressions of concern came in. But yeah, it's a very thorough process. And I think that the RIC took it with an appropriate level of seriousness that, you know, you are really sort of innocent until proven guilty.
And we had to have the burden of proof. Process in place for paternity and sterility is really rigorous. And if you see a letter of concern or a retraction for paternity and sterility, a lot of due diligence went into that.
That's not just an accusation. So I just want to leave it there that, you know, thank you for the service for all the people that are doing it. But there's a lot of thought and due diligence between those actions, so take them seriously is my point.
That's why I asked. So thanks. That's very reassuring for all of the readership out there.
And thanks again for doing the work. 100%. I am so proud to be part of a journal that is not sweeping this under the rug or trying to hide it.
Instead, we're tackling it head on and being very transparent and very robust with the process. Unfortunately, some of these studies have influenced meta-analyses and have influenced practice committee opinions, even those of our own ASRM. So this is why it's so important, because it does affect how we practice.
And this is why FNS On Air podcast is important, because we're learning about the most up-to-date, rigorous research and how it affects our practice. Eve, Kurt, Kate, it is so great to be back with you guys. Thank you for teaching me again today.
I learned a lot and had a great time with you. Until next month, it was great to see everyone. Thanks, everybody.
This concludes our episode of Fertility and Sterility On Air, brought to you by Fertility and Sterility in conjunction with the American Society for Reproductive Medicine. This podcast is produced by Dr. Molly Kornfield, Dr. Adriana Wong, Dr. Elena HogenEsch, Dr. Selina Park, Dr. Carissa Pekny, and Dr. Nicholas Raja.
