White Paper in Response to the "Response to the NEW YORK Magazine” by Santiago Munné, Chief Science Officer of CooperGenomics

Posted on Oct 27, 2017

OPINIONs 011: October 27, 2017


On October 6, 2017, Santiago Munné, PhD, posted a formal response to Stephen S. Hall’s article in the September 18- October 1, 2017 issue of NEW YORK magazine. This was his second response to the article. A prior response in a chain e-mail was distributed by the company CooperGenomics, signed by Santiago Munné, PhD, and Mark Hughes, MD, PhD. Both scientists used to be long-standing owner-laboratory directors of two of the nation’s leading preimplantation genetic screening laboratories, Reprogenetics in New Jersey, and Genesis in Detroit, Michigan, and in 2016 sold their lab-companies to CooperSurgical Inc. Santiago Munné is now the Chief Science Officer of the genetics division of the company, called CooperGenomics.

This background information is important because it suggests that both individuals, whatever their widely recognized scientific achievements in the past, very obviously also have potential commercial conflicts. We here address Munné’s later, October 6, communication because it was more detailed and outrageous.

Munnés Response Memorandum

"the misperceptions in the recent NEW YORK Magazine, which created a lot of anxiety in patients and their doctors by hyping a minority view"

Munné started his commentary by noting that “he wanted to address the misperceptions in the recent NEW YORK Magazine, which created a lot of anxiety in patients and their doctors by hyping a minority view and confusing the majority.”

As we noted in the October issue of the CHR VOICE, we strongly disagree with this statement, especially considering the truly Herculean efforts Stephen S. Hall, the highly regarded medical writer of the article, undertook to quote prominent opinions on both sides of the divide fairly (facts were often double- and sometimes even triple-checked). Indeed, he also spoke extensively to Munné, himself, even though Munné, in his here discussed response, now claims to have been misquoted. Paradoxically, none of the many other physicians and scientists quoted by Hall, however, felt misquoted.

Hall’s article, in our opinion, was extremely objective and did notreflect misperceptions relating to PGS.” We are also unclear how by allowing objective expression of opinions on both sides, an article can be accused of “hyping a view.” Munné apparently believes that only his view (and that of like-minded compatriots) is valid, and any representation of opposite views should be prevented because it would be “confusing” to the public.

This is, of course, not only a patronizing view of scientific discourse but also reveals a rather low opinion of patients and physicians who, he feels, are getting confused by facing alternative opinions. It also demonstrates a rather surprising lack of understanding of science, because, if science taught the world one important fact, it is that majority opinions are not always correct opinions. Otherwise, the world would still be flat!

Studying Munné’s latest memorandum about PGS (in a 3rd rebranding campaign given the new acronym, preimplantation genetic testing for aneuploidy, PGT-A), him still representing a majority opinions, appears increasingly unlikely. The rather disheveled nature of his presentation and arguments, and the detailed responses in this White Paper, we believe, leave him with, unfortunately, little scientific credibility.

"definition of terms"

In keeping with CooperGenomic’s goal of educating and empowering patients,” Munné then claims to offer definition for terms, which Hall, in his opinion “confused.” He, for example, defines aneuploidy as “all cells tested by PGS are abnormal” and differentiates this diagnosis from a diagnosis of mosaicism, where in his opinion “some cells of the embryo are abnormal;” and he defines euploidy as “all cells tested are normal.”

That Munné still offers such simplistic definitions, is astonishing. Not even one of his above quoted definitions is, indeed, correct. Even if all cells in a single trophectoderm biopsy are abnormal, to still argue that this embryo should be outright discarded, is with current knowledge simply absurd. The reason is that mosaicism in trophectoderm (TE) of blastocyst-stage embryos is very common (i.e., many and maybe all embryos have aneuploid cell clusters in their TE; extensively reviewed by 1,2).

Mosaicism is also not evenly distributed but clonal. Therefore, one TE-biopsy of 5-7 cells at an arbitrarily chosen location on the TE globe, may fall either smack in the middle of an aneuploid cluster, smack in the middle of normal euploid TE or in the borderline area between both, getting a few normal as well as abnormal cells. Under Munné’s definitions, the first biopsy would suggest an “aneuploid” embryo, the second biopsy an “euploid” embryo and only the third biopsy would result in diagnosis of a “mosaic” embryo.

In other words, according to Munné, an embryo is only “mosaic” if a single TE biopsy demonstrates mosaicism (i.e., at least 2 different cell lines), while looking at embryos correctly in a biological way, a “mosaic” embryo is characterized by more than one chromosomally normal cell line anywhere within in the embryo; indeed, not only in TE but also including the inner cell mass (ICM).

Because mosaicism is now recognized as a very common phenomenon in blastocyst-stage embryos, it should not surprise that studies demonstrated that the accuracy of PGS in determining whether an embryo can be transferred or should be discarded, is equal to a coin flip (reviewed in 3). Though we do not recommend coin flips to make important medical decisions, a coin flip would at least spare patients approximately $4,000-5,000 in additional expenses for already too costly IVF cycles.

Why does it matter if embryos are normal or abnormal?

Munné then asks an interesting question, “Why does it matter if embryos are normal or abnormal?” He, however, answers his question with a categorically incorrect answer, when stating that, “chromosomal abnormalities result in the embryo not implanting or in a miscarriage.”

To see such an indisputably wrong statement from a leading PGS/PGT-A experts is rather astonishing, but even more astonishing is that CooperGenomics, a subsidiary of CooperSurgical Inc., would permit such a statement from its CSO.

Some chromosomally abnormal embryos, of course, do really not implant and/or lead to miscarriages, but many others do not. Indeed, certain chromosomal abnormalities can lead to live births (i.e., Down’s syndrome, Turner syndrome, etc), and PGS/PGT-A would be of great benefit if it accurately prevented such abnormal births.

The reason why Munné’s statement is so misleading is that a single TE biopsy cannot reliably determine whether an embryo is chromosomally normal or not. Since this was recently in detail discussed in the literature,1-3 and in the CHR VOICE, we will here not be repetitive. Only so much: Close to 100 normal pregnancies have been reported so far after transfer of what, after PGS/PGT-A, were believed to be chromosomally abnormal embryos. By suggesting that PGS/PGT-A has the ability to define which embryos can be transferred and which should be disposed of, Munné is highly misleading! The principal problem with PGS/PGT-A is that the procedure cannot reliably discriminate, at blastocyst-stage, between truly chromosomally abnormal embryos and embryos with clinically irrelevant degrees of chromosomal mosaicism (i.e., islands of abnormal cells in TE).

There are three biological reasons supporting this conclusion:

1 The complete status of the TE cannot be determined by a single TE-biopsy involving only 5-7 cells (the average cell count of a TE biopsy). The reason is that the TE in, likely, most embryos is mosaic. Random biopsies’ results will, therefore, depend on where the biopsied cells come from: If they come from a small area of chromosomally abnormal TE cells, the diagnostic assumption from s single biopsy would be the embryo is chromosomally abnormal (even if the rest of the TE is largely normal), leading to many false-positive assumptions about embryo ploidy. If the cells come from an area of normal cells, suggesting a totally normal euploid TE, even if the rest of the TE is largely abnormal, the result would be false-negative assumptions of embryo ploidy. Statistically least likely, the biopsy is taken from a borderline area of the TE between chromosomally normal and abnormal cells and, therefore, catches some chromosomally normal as well as abnormal cells. Only in this last case, would current PGS/PGT-A guidelines describe such embryos as “mosaic.”

Embryos, however, also would be “mosaic” if, as described above, biopsies were either false- positive or false-negative and one or more other (after a single biopsy unknown) cell clones populated the TE or ICM. Yet, this kind of TE mosaicism would be unknown after only a single random TE biopsy. Indeed, even if the single biopsy is investigated with most state-of-the-art technology (i.e., NGS platforms), mosaicism in single biopsies may also still be overlooked because current equipment detects only DNA volume over 20% of total DNA.

Correct diagnosis of mosaicism is, however, of importance because at last some “mosaic” embryos have been demonstrated to be transferrable and, in surprising numbers, will lead to pregnancy and live birth.4-8 Until July 2016, supposedly “mosaic” embryos, like embryos believed to be “aneuploid,” were, however, uniformly disposed of because laboratories reported embryos as “abnormal,” even if the presence of aneuploidy was minimal. By now, close to 100 chromosomally normal pregnancy have been reported after transfer of supposedly “aneuploid”/”mosaic” embryos, many, indeed, in a recent multicenter study, of which Munné was the lead author.8

Munné’s statement that “chromosomal abnormalities result in failure to implant or in miscarriage,” is, therefore, at best half-truth, and contradicted by his own study. Truly chromosomally abnormal embryos (i.e., true embryo aneuploidy), indeed, as of this point in our knowledge base, should not be transferred. The problem the PGS/PGT-A industry created for IVF providers and their patients, however, is that a PGS/PGT-A based on a single 5-7-cell TE-biopsy, for biological and technical reasons, cannot accurately determine whether an embryo is truly normal, abnormal or mosaic.

2 This conclusion is further strengthened by the recognition that the TE does not perfectly represent the inner cell mas (ICM). Studies have demonstrated discrepancies in the 15 to approximately 30% range.9 And that is not even the end of the story: The TE represents an early cell lineage that forms the placenta, while the ICM forms the embryo. In other words, in PGS/PGT-A, we are biopsying the placenta in an attempt to determine what is going on in the fetus. Yet, it has been known for decades that placentas from term pregnancies contain often islands of chromosomally abnormal cells, while offspring are chromosomally completely normal.

3 Further evidence that a single TE-biopsy cannot reliably determine whether an embryo is chromosomally normal or not, comes from experimental research in animal models and with human stem cells. In a beautiful mouse study reported in 2016 by investigators from Cambridge University in the UK, the ICM at blastocyst stage had to be aneuploid in over two-thirds of cells to result in no normal pups. Even if only one-third of cells at that embryo-stage were chromosomally normal, one-third of pups were born normal. Once the ICM contained over 50% chromosomally normal cells, all pups were born chromosomally normal.10

The investigators further demonstrated that, downstream from blastocyst-stage, cells of the ICM had a rather remarkable ability to “commit suicide” if they were chromosomally abnormal, while chromosomally normal cells prospered and took over, thereby leading to growth and development of normal pups.

This ability to self-correct is of great potential interest not only for here discussed biological processes but may also have great significance for cancer biology because cancer, which like the early embryo, is characterized by significant aneuploidy, very obviously has lost the ability to self-correct. Understanding this process better may, therefore, have great therapeutic potential for invasive cancers.

Proponents always point out that this ability to self-correct has so far only be shown in rodents, and they are correct in this argument. Such experiments with human embryos are, of course, technically as well as ethically difficult to perform. What these proponents, however, overlook when making this argument is that quite a number of studies of human embryonic stem cells (hESCs), derived from the ICM, have demonstrated the same ability of self-correction, with aneuploid ICM cells giving rise to chromosomally completely normal stem cell lines.

In addition to the three biological reasons why PGS/PGT-A cannot reliably determine whether an embryo is normal or not, there is also rapidly increasing and difficult to contradict clinical evidence for this conclusion, and that is the previously noted fact that so-far close to 100 chromosomally normal pregnancies, many already delivered, have been reported in the literature.4-8 As we in last month’s issue of the VOICE in detail discussed, CHR is proud to have reported the first healthy live births in the world after transfers of by PGS/PGT-A aneuploid/mosaic-declared embryos at a time when everybody else, still, simply disposed of these embryos.4,5

The most inexcusable aspect of Munné’s statement about the importance of normal or abnormal embryos is, therefore, the unstated assumption he is suggesting to IVF centers and their patients, that PGS/PGT-A really does have the ability to accurately determine whether an embryo is chromosomally normal or not. If he, indeed, had this ability, CHR would be his first client. Since PGS/PGT-A really does not have this ability, he is only selling the equivalent of snake oil!

He then notes what the PGS/PGT-A industry only as of July 2016, suddenly, discovered, when the PGDIS published new reporting guidelines, stating that, amongst all diagnostic platforms used by PGS laboratories up to that point, only Next Generation Sequencing (NGS) should be used going forward because it was the only platform that could diagnose mosaicism in a single biopsy.11 He, of course, does not mention that for many years he and most other commercial laboratories used other platforms, which they now, suddenly, consider inadequate. At the same time, throughout his memorandum, he repeatedly offers in support of his opinions data that were generated during use of these “inadequate” platforms.

those embryos with 0 normal cells (on TE biopsy) are fully aneuploid, and those with all normal cells are euploid (normal)"

Under the heading, “How does NGS for PGS work?” Munné then makes the remarkable statement that “those embryos with 0 normal cells (on TE biopsy) are fully aneuploid, and those with all normal cells are euploid (normal).”

As in preceding paragraphs explained in detail, considering current knowledge in the field, this is really a remarkably ignorant statement. There is, simply, nothing more to add!

“… we can detect 1 in 5 (20%) to 4 in 5 (80%) abnormal cells in the biopsy."

Under the heading, “How do you detect mosaic embryos?” Munné then continues, “… we can detect 1 in 5 (20%) to 4 in 5 (80%) abnormal cells in the biopsy. Those in-between the 20-80% range, we call then mosaic. Mosaics have lower chances of implanting, higher chances of miscarrying. About 18% in young women have mosaic embryos, but the rate of mosaicism goes down as age goes up because they become fully abnormal for other chromosome defects. Women 40 and above have about 9% mosaic embryos.

He, of course, is again mistaken: Even best current NGS platforms detect aneuploidy in any biopsy specimen only above 20% DNA content. Assuming that the average TE biopsy includes five cells, he here claims that, because of the 20% sensitivity threshold, NGS, therefore, detects even one aneuploid/mosaic cell out of five. As previously noted, the literature, however, suggests that the average cell number in TE biopsies is closer to six or seven cells. Whatever the number really may be, every embryologist will confirm that it is, simply, impossible to limit a TE biopsy exactly to five cells. Following Munné’s logic, in a 6-cell biopsy, one aneuploid cell would not be discovered by NGS because, at 16% of all DNA content, the sensitivity threshold for NGS would not be reached. For a 10-cell biopsy, 20% sensitivity would already require two or more cells for detection, etc.

Similarly, the upper cut-off of 80% DNA content, which defines the cut-off between “mosaic” and true “aneuploidy,” is equally senseless because Munnés argument that this represents four aneuploid cells in a 5-cell biopsy, is for the same simple mathematical reasons not sustainable: Assuming a 6-cell biopsy, 4 aneuploid cells would no longer represent 80% but only 66% of DNA load, well within what even Munné now considers the “mosaic” range. Since no embryologist doing TE biopsies ever knows with certainty how many cells were biopsied, and since cells on many occasions are damaged during the biopsy and, therefore, contain no measurable DNA, it appears astonishing that commercial laboratories would base their diagnostic cut-offs on completely baseless assumptions. One, indeed, has to wonder why, under these circumstances, the Food and Drug Administration for so many years has tolerated a basically unvalidated laboratory service, leading to such significant consequences as disposal of human embryos during IVF.   

Munné’s explanation how his and other PGS/PGT-A laboratories now “detect mosaic embryos,” therefore, makes absolutely no sense. It, however, completely parallels the July 2016 guidelines from the PGDIS.11 Even if by mere chance a TE biopsy is taken in a borderline area between chromosomally normal and abnormal cells, NGS, still, for technical reasons will miss low levels of aneuploid cells and, therefore, mosaicism.

Whatever mosaicism rates are reported even with NGS, therefore, still underestimates real mosaicism prevalence in blastocyst-stage embryos even in single biopsies and, obviously, multiple biopsies of TEs would find more mosaicism than single biopsies. Since single TE- biopsies are taken at random and do not reflect the total TE, by Munné reported alleged statistical facts, therefore, at best, are based on significant underestimates of TE mosaicism in human embryos at blastocyst-stage but, more likely, are really worthless.

mosaic embryos have lower chances of implanting and higher chances of miscarrying

Munné’s statement that, “mosaic embryos have lower chances of implanting and higher chances of miscarrying,” is also unsupported by evidence. Not only are there no validated studies in the literature to support this statement (two studies that made these claims used discredited diagnostic platforms and only single TE biopsies). Indeed, existing evidence suggests surprisingly robust clinical pregnancy and live birth rates and surprisingly low miscarriage rates after transfer of aneuploid/mosaic embryos.4-8

CHR investigators recently also refuted in a manuscript, currently submitted for publication, the claim made by Munné et al in a recent publication in Fertility and Sterility 8 that a 40% mosaicism threshold in a TE biopsy differentiated between better and poorer pregnancy chances. Using the study’s own published data, by constructing ROC curves for different mosaicism percentages, CHR’s investigators demonstrated absolutely no differences in pregnancy rates between degrees of mosaicism in transferred embryos.12 Considering our comment above about the accuracy of mosaicism percentages in TE biopsies, one, indeed, would also not expect any such differences.

This is a very important point to understand because even supporters of PGS/PGT-A no longer claim, as they until very recently did, that PGS/PGT-A improves clinical pregnancy and live birth rates in association with IVF. The new claims in support of the use of PGS/PGT-A are that the procedure (i) shortens time to conception by allowing selection of embryos with higher implantation potential (i.e., lower mosaicism) and (ii) reduces miscarriage rates. Our reanalysis of above cited study by Munné et al,8 establishes that the first claim is incorrect. That PGS/PGT-A reduces miscarriage rates has recently been refuted in at least two studies from highly reputable academic fertility centers on both coasts 13,14 and in a CHR study of donor-recipient cycles, which is in press.15

Can mosaic embryos make babies?

Under the heading, “Can mosaic embryos make babies,” Munné directly addressed CHR’s first publications reporting live births after transfer of “aneuploid” embryos 4,5 by arguing that CHR’s cases were investigated with an “older technique that could not differentiate aneuploidy from mosaics.”

In that statement, he was at least partially correct since CHR transferred so-called “aneuploid” embryos that led to healthy live births for the first time in 2012, when NGS platforms were not yet in use. What he, however, failed to note was that some of CHR’s earliest patients who received such transfers had their embryos evaluated by what then was Munné’s own PGS laboratory in New Jersey, Reprogenetics, which he, since, sold to CooperGenomics. And his (and others’) laboratories in those years signed out these embryos as “aneuploid.”

Whether these embryos, based on the new sign-out guidelines of the PGDIS of July 2016, would now be still classified as “aneuploid” or, potentially, as “mosaic,” is impossible to know but also completely irrelevant, since, as we here in detail explained, these new _PGDIS _guidelines are arbitrary and lack all logical underpinning as well as clinical validation studies.

His comment is, however, particularly inappropriate in view of his own, previously noted recent publication,8 in which the authors reported 50% clinical ongoing pregnancy rates in transfers of mosaic embryos with single monosomies and trisomies in relatively poor prognosis patients who had no euploid embryos for transfer. In other words, Munné, himself, reported unexpectedly high ongoing clinical pregnancy rates after transfers of embryos, which until 2016 would have been uniformly disposed of as “chromosomally abnormal.” How he, therefore, can still question the utility of such transfers is astonishing!

"What was the problem with Array CGH as it relates to mosaicism?

Munné continues his memorandum by asking, “What was the problem with Array CGH as it relates to mosaicism?” The purpose of this question is a rather obvious attempt to whitewash the false information about PGS he and other PGS proponents provided to IVF practitioners and patients over many years. After all, CGH was one of the diagnostic platforms many PGS laboratories, including his own, utilized over many years before, only recently, switching to NGS platforms.

Now, even by him described as “inferior,” he is trying to minimize the very obvious damage from the unvalidated utilization of CGH (and other platforms) over the years. Claims in here discussed memorandum, again, are highly misleading. For example, that, “Of the 80% that would have been classified as euploid/normal with CGH, only 4% now would be classified a true mosaic by NGS”, while, “20% of previously classified mosaic embryos would now be classified as aneuploid,” is simply false!

Before July 2016, when the new PGDIS guidelines were published,11 practically all PGS laboratories reported results only bi-modal, as either “normal/euploid” or “abnormal/ aneuploid.” This, likely, would still be the reporting scheme if CHR investigators and a small number of colleagues in the U.S. and Europe had not started transferring so-called “aneuploid” and/or “mosaic” embryos, reporting healthy chromosomally normal births.4-7 Though, as noted before, for a good number of years evidence already strongly suggested that PGS, for simply biological reasons, was unable to correctly determine which embryos should or should not be transferred, the PGDIS did not revise guidelines for PGS until increasing numbers of healthy births after transfer of “abnormal” embryos could no longer be explained away.

Only after the new PGDIS guidelines were published (and the procedure renamed as PGT-A), did laboratories, suddenly switch to a tri-modal reporting system of “normal/euploid,” “mosaic” and “abnormal/aneuploid,” and was NGS formally declared the “only” diagnostic platform to be used because it was the only platform capable of detecting mosaicism within a single TE biopsy specimen.11

Though even the relatively small discrepancies in testing results claimed by Munné are worrisome, they, of course, do not reflect reality. The difference is dramatically bigger than Munné wants us to believe, and will be discussed shortly. In order to demonstrate Munné’s highly selective use of sources, only so much before that: He then cites a 2012 study by Scott et al as “the best so-far,” even though it utilized a PGS platform, likely, even inferior to CGH, and also had considerable other shortcomings, detailed elsewhere.1-3

Highly selected citations are, of course, very frequently the backbone of arguments in the medical literature. In the PGS/PGT-A debate, the dispute between proponents and opponents of PGS/PGT-A can, however, be easily whittled down to a very simple question: What is the accuracy of PGS/PGT-A in determining whether an embryo can be transferred or should not be transferred?

Though not spelling it out, Munné indirectly addressed the question by asking, “How many embryos are (mistakenly) discarded?”

How many embryos are (mistakenly) discarded?”

He starts his answer by accusing Richard Paulson, MD (also this year’s President of the ASRM), who was extensively quoted in the NEW YORK magazine article (and also offered an excellent personal explanation of his study in a video attached to the article), of “guessing from thin air” that “40% of embryos are discarded (because of false-positive diagnoses), while solid data point to a mere 2-4%.” Expressing the hope that “he was misquoted” by the author of the article, as he claimed to have been himself, Munné, however, does not mention that the information attributed to Paulson in the article was exactly what Paulson had published just weeks earlier in Fertility & Sterility as a well thought through mathematical model,16 and what he presented in the attached video. In other words, Hall did not misquote Paulson in his article!

We noted in last month’s VOICE that, based on CHR’s own research data, Paulson’s 40% are, likely, still somewhat conservative, and that the real rate of false-positive diagnoses may even be higher. But what is really fascinating about this Munné statement, is that an expert of his standing, considering what is now known about early developmental stages of human embryos, would, instead, suggest a bizarrely unrealistic 2-4% rate!

He then, however, under the heading, “What if my lab is wrong?” notes that, “each test reported (by a laboratory) should also note its error rate.” We, of course, agree with this statement with the one caveat that the reported error rate also has to be accurate. If quoted error rates are false, referring physicians and patients are obviously misled.

"only aneuploidy increases with maternal age, not mosaicism"

Under the next heading, “Do the number of mosaics increase with age like aneuploidy does?” Munné again becomes personal with CHR investigators and some colleagues, when he notes that, “the argument of Gleicher, Braverman and Vidali is that with advancing maternal age the likelihood of having normal embryos diminishes and the risk of throwing away mosaic embryos (which they mixed up with aneuploid) increases. However, only aneuploidy increases with maternal age, not mosaicism.”

Munné is, of course, again incorrect, and rudely misquotes Gleicher et al.: First, CHR investigators did not mix up mosaic and aneuploid embryos because they reported embryos as they were reported out by leading PGS laboratories at the time, including Munné’s own laboratory, Reprogenetics. Again, until July 2016, PGS laboratories did not report “mosaic” embryos, and reported the presence of any aneuploidy as “abnormal” and “not recommended for embryos transfer.”

As already extensively discussed before, the error lies with Munné and likeminded proponents of PGS/PGT-A, who still claim that a single TE-biopsy can reliably determine whether an embryo is 100% normal/euploid, mosaic, or 100% abnormal/aneuploid. PGS/PGT-A cannot do this in either younger or older women.

CHR investigators and colleagues also never in any of their publications or, for that matter in The VOICE, made the “argument” ascribed to them by Munné. What they really have published on many occasions is that losing an embryo to a false-positive diagnosis (i.e., disposing of an embryo incorrectly and unnecessarily) affects older women and younger women with low functional ovarian reserve (FOR) statistically more severely than younger women with good FOR. This is an absolutely correct statement because older women and women with low FOR usually produce small embryo numbers. Each embryo, therefore, is relatively more important for statistical outcomes.

All of this, of course, has absolutely nothing to do with whether mosaicism is age-dependent or not. For readers who, nevertheless, are interested in a thorough discussion of the subject, we recommend an excellent recent review by a geneticist who really knows what he is talking about.17

"a mosaic embryo only has a 1.6% chance in an IVF clinic of success

Munné concludes this paragraph of his memorandum by addressing his readership directly with the following sentence: “Please understand, a mosaic embryo only has a 1.6% chance in an IVF clinic of success.” In other words, after, himself, reporting a 50% ongoing clinical pregnancy rates for women wo received embryo transfers with monosomic or trisomic mosaic embryos,8 he here, in a communication to his “clients,” claims only a 1.6% chance for such embryos.

"we can prioritize transferring normal embryos, which now have lower chances of being mosaic

But self-evident contradictions do not end here. Under the next heading, “What are the success rates with the NGS technique?” Munné initiates the paragraph with the following statement:  “Now that we can identify mosaics better with NGS, we can prioritize transferring normal embryos, which now have lower chances of being mosaic.”

It is difficult to know, where to start in demonstrating how incorrect this single sentence is: (i) When Munné talks about “mosaic” embryos, he really, again, only refers to embryos with a “mosaic” TE-biopsy. He does not consider the previously discussed fact that mosaicism may not be apparent in a single TE-biopsy. (ii) As we also already in detail discussed, even best NGS platforms still miss mosaic TE-biopsies since their sensitivity threshold is 20% of total DNA load. This means that, even with NGS, at least some so-called “normal” embryos will, still be “mosaic.” Similarly, since the definition “aneuploidy” in a single TE-biopsy by over 80% mosaicism is also non-sustainable, NGS is also unable to reliably differentiate between “mosaic” and “aneuploid” TE-biopsies. (iii) There is no evidence in the literature that transfers of so-called “mosaic” embryos achieve lower pregnancy rates than transfers of by PGS declared “normal” embryos. Indeed, Munné’s own recent publication in Fertility & Sterility suggests otherwise, considering the surprisingly high ongoing pregnancy rates after transfer of so-called “mosaic” embryos.8 Before that, CHR investigators and Italian as well as Spanish investigators also reported unexpectedly high pregnancy and live birth rates with transfer of such embryos.4-7

abnormal mosaic (not aneuploid) embryos are now expected to have even fewer chances than the 2-4%, previously reported to produce a viable pregnancy

Munné then, however, even doubles down by stating that “abnormal mosaic (not aneuploid) embryos are now expected to have even fewer chances than the 2-4%, previously reported to produce a viable pregnancy.” Considering his own, above repeatedly cited, publication,8 one is left truly speechless by the very obvious contradictions between his own published research and the statements he offers in support of PGS/PGT-A in the memorandum we are here addressing.

He then asks the very appropriate question, “Should IVF cycles include PGS?” and, not surprisingly, his answer is a resounding yes. The first argument he makes in support is that PGS facilitates elective single embryo transfer (eSET). While this, in principle, is a correct statement, eSET, in itself, has remained a highly controversial subject. Especially in older women and/or women with low FOR, eSET, however, is not even by most proponents considered an appropriate clinical option because in such patients, embryo losses from extended embryo cultures and false-positive PGS/PGT-A diagnoses often prevent patients from even reaching embryo transfer.18 Munné here, again demonstrates a complete lack of clinical understanding of some of the most basic clinical dynamics in IVF practice.

Without PGS, IVF cycles result in more miscarriages, especially in patients over age 40

This is also apparent in the next statement that, “Without PGS, IVF cycles result in more miscarriages, especially in patients over age 40.” Not only is there no evidence in the literature to support such a statement but at least three recent studies (Stanford, CA,13 Cornell, NY 14 and CHR, NY 15) suggested no such outcome benefits from PGS. But what really demonstrates Munné’s clinical ignorance best, is his argument that the NEW YORK magazine “article failed to mention that having no normal embryos and no mosaic embryos leads usually to the patient choosing egg donation, a procedure that has very high success rates.”

To take his totally distorted view of clinical IVF, demonstrated by this one sentence, to the extreme, why then not take every fertility patient straight into egg donation? No fertility patient’s IVF outcomes, practically, can ever compete with the pregnancy chances offered by a 20-year-old egg donor! The here expressed notion that any patient would benefit in any measure from prematurely being “pushed” into egg donation is, indeed, so bizarre that it could only come from the pen of a non-physician.

The real answer to Munné’s question whether IVF cycles should include PGS, therefore is an emphatic no.

Munné’s conclusions about the NEW YORK magazine article

Munnés conclusion section is also rather bizarre: He starts by claiming that, “there is no solid evidence that aneuploid embryos detected by the most advanced techniques (NGS) can self- correct (downstream after blastocyst stage).” As already noted, he, again, is misrepresenting facts: There is solid evidence in animal studies and there is also solid evidence from stem cell studies in humans that aneuploid cells from the ICM can result in chromosomally normal cell lines. For further detail, the reader is referred again to previously noted recent review.17

Though demanding “solid evidence” here, Munné and other PGS/PGT-A proponents, interestingly, never expressed the same demand for solid evidence for the effectiveness of PGS/PGT-A. Had they done so before introducing the procedure as an add-on to IVF, PGS/PGT-A, likely, would never have entered clinical IVF practice because, to this day, it is still seeking a clinical indication. It is difficult to understand how an important test, meant to decide whether an embryo should be transferred or disposed of, is permitted to enter clinical practice without prior clinical validation. It is even more difficult to understand how this has been allowed on three consecutive occasions, after prior versions were found to be clinically ineffective.

Even more remarkably, as Munné again does in his memorandum, PGS/PGT-A proponents over all those years succeeded in putting the burden of proof on opponents of the procedure, while proof of concept, of course, should be provided by proponents of PGS/PGT-A. The burden of proof that human embryos do not self-correct downstream from blastocyst stage, really lies with him and likeminded proponents because a TE-biopsy at blastocyst-stage, of course, would be senseless if such corrections are possible.

This is, however, how the PGS/PGT-A laboratory community has been marketing the procedure since first introducing the concept without prior validation. Once, after years of clinical use, PGS 1.0 was finally pronounced worthless by professional societies,19-21 there was a smooth transition to PGS 2.0, again without prior validation studies. Now, with PGS 2.0 by births of healthy offspring after transfer of allegedly chromosomally abnormal embryos demonstrated to be ineffective in differentiating normal from abnormal embryos, PGS proponents, again without prior validation studies, came up with a new name (PGT-A; i.e., PGS 3.0) and new indications for the procedure (I.e., quicker time to pregnancy and lower miscarriage rates).

Munné then attempts to further absolve the PGS/PGT-A laboratory community from responsibility for the tens of thousands of healthy embryos that were over the years mistakenly disposed of by stating that, “Genetic testing labs do not make transfer recommendations nor do they discard embryos.”

Technically this is, of course, correct; practically, however, this sentence, as every IVF center will attest to, is a pretty outrageous misrepresentation because IVF centers explained PGS to their patients based on information they received from the PGS/PGT-A laboratory community. Moreover, when IVF centers disposed of embryos after receiving biopsy reports from their PGS/PGT-A laboratories, they did so because they were advised by those laboratories that embryos were “abnormal” and not suited for transfer. For the laboratory community now to suggest that, “laboratories do not make transfer recommendations nor do they discard embryos” is, therefore, not only misleading but rather despicable. IVF centers and their patients should, however, take note of Munné’s reassignment of responsibility when in the future submitting TE-biopsies for testing.

In making this comment, Munné also ignores that the PGDIS, for all practical purposes the PGS/PGT-A community’s professional organization, published distinct guidelines for all aspects of PGS/PGT-A, including which embryos should or should not be transferred and, even, in which order.11 Many of Munné’s statements in his memorandum, indeed, fully reflect the most recent PGDIS modification of July 2016. It, therefore, is rather remarkable that this laboratory community is now simply shrugging off all responsibility for the unnecessary disposal of tens of thousands of potentially healthy embryos!

Munné then criticizes the New York Magazine article for not mentioning four randomized clinical trials, “all supporting PGS as improving ongoing pregnancies (with IVF).” Where this statement suddenly comes from in the conclusion section is unclear because, as we previously noted, even proponents of PGS/PGT-A no longer make this claim (indeed, Munné, himself, in a recent conference in Milan, Italy, distanced himself from this claim). Those alleged prospectively randomized studies he is referring to, uniformly, were either poorly designed and/or misinterpreted in their results.1-3

And then, again for unclear reasons in the conclusion section, he attacked the credibility of CHR’s publications on the subject of PGS when stating, “The Gleicher paper reporting 7 babies born after replacing abnormal embryos did not follow the standard procedure that we have for a discrepant result” then going onto “how they reassess discrepant results.”

He, however, once again, is only trying to obfuscate: There were no discrepant results in the seven live births CHR (and colleagues Braverman and Vidali) published. Those cases involved patients who sent their embryos to reputable laboratories for PGS, including Munné’s own laboratory, and were told that all of their embryos were “aneuploid.” CHR (and colleagues) then, nevertheless, selectively, transferred those embryos, starting in 2012, when the concept of a “mosaic” PGS result was not yet on the horizon because NGS platforms were not yet in use.

He then also insinuates that, “pregnancies may have been conceived spontaneously in these patients (”in vivo”), that embryos may have been switched within or between cycles and patients” and that “other errors” may have occurred. This comment is not only insulting but truly outlandish because he, of course, never doubted the pregnancies he reported 8 as similarly “suspicious.” His comment, however, again demonstrates that the PGS/PGT-A community, simply, has no shame!

The ASRM may be interested in finding out that Munné, furthermore, claims in his document that, “The ASRM has produced guidelines which further detail and recommend the PGS approach.” To the best of our knowledge, no such guidelines exist, and the ASRM has not recommended “the PGS approach.” Indeed, a still preliminary opinion that has been circulating among ASRM members, voiced exactly the opposite sentiments, namely that current evidence does not support the utilization of PGS.

Practically the only sentence in this memorandum in which Munné speaks to the truth, is his concluding sentence, when he states, “It’s very important patients and clinics have all the facts and are not misled.” We completely agree and, for exactly this reason, are issuing this White Paper because Munné’s memorandum is nothing but one long list of, at times, rather outrageous misrepresentations and distortions of facts.


  1. Orvieto R, Gleicher N., Should preimplantation genetic screening (PGS) be implemented in routine IVF practice? J Assist Reprod Genet 2016; 33:1445-1446
  2. Gleicher N, Orvieto R., Is the hypothesis of preimplantation genetic screening (PGS) still supportable? A review. J Ov Res 2017; 10(1):212016;
  3. Gleicher N, Kushnir VA, Barad DH, Orvieto R. Recent reporting changes for preimplantation genetic screening (PGS) within the context of transferring mosaic embryos. J Assist Reprod Genet; In press;
  4. Gleicher N, Vidali A, Braverman J, Kushnir VA, Albertini DF, Barad DH., 2015. Further evidence against use of PGS in poor prognosis patients: report of normal births after transfer of embryos reported as aneuploid. Fertil Steril 2015;104(Suppl) 3:e9
  5. Gleicher N, Vidali A, Braverman J, Kushnir VA, Barad DH., Hudson C, Wu YG, Wang Q, Zhang L, Albertini DF. Accuracy of preimplantation genetic screening (PGS) is compromised by degree of mosaicism of human embryos. Reprod Biol Endocrinol 2016;14:54
  6. Greco E, Giulia Minasi M, Florentino F., Healthy babies after intrauterine transfer of mosaic aneuploid blastocysts. N Engl J Med 2015; 373:2989-2090
  7. Morales R, Lledó B, Ortiz JA, Ten J, Lláce J, Bernabeu R. Embryos showing mosaicism in trophectoderm cells can achieve good pregnancy rates. Hum Reprod 2016;31 (Supl 1): i14, O-030
  8. Munné S, Blazek J, Large M, Martinez-Ortiz PA, Nisson H, Liu E, Tarozzi N, Borini A, Becker A, Zhang J, Maxwell S, Grifo J, Barbariya D, Wells D, Fragouli E. Detailed investigation into the cytogenic constitution and pregnancy outcome of replacing mosaic blastocysts detected with the use of high-resolution next-generation sequencing. Fertil Steril 2017; 2017.05.002
  9. Orvieto R, Shuly Y, Brengauz M, Feldman B., Should preimplantation genetic screening be implemented in routine clinical practice? Gynecol Endocrinol 2016;12:1-3
  10. Bolton H, Graham SJ, Van der Aa N, Kumar P, Theunis K, Fernandez Gallardo E, Voet T, Zernicka-Goetz M., Mouse model of chromosome mosaicism reveals lineage-specific depletion of aneuploid cells and normal developmental potential. Nat Commun.2016;29;7:11165.
  11. PGDIS, Preimplantation Genetic Diagnosis Society (PGDIS( position statement on chromosome mosaicism and preimplantation aneuploidy testing at the blastocyst stage, Chicago, Illinois; July 19, 2016; accessed April 5, 2017
  12. Kushnir VA, Darmon SK, Albertini DF, Barad DA, Gleicher N. Sgree of mosaicism in trophectoderm does not predict pregnancy potential: a corrected analysis of pregnancy outcomes following transfer of mosaic embryos. Submitted for publication;
  13. Murigappan G, Shahine LK, Perfetto CO, Hickok LR, Lathi RB., Intent to treat analysis of in vitro fertilization and preimplantation genetic screening versus expectant management in patients with recurrent pregnancy loss. Hum Reprod. 2016; 31:1668-1674.
  14. Kang HJ, Melnick AP, Stewart JD, Xu K, Rosenwaks Z. Preimplantation genetic screening: who benefits? Fertil Steril 2016;106(3):597-602
  15. Barad DH, Darmon SK, Kushnir VA, Albertini DF, Gleicher N. Impact of preimplantation genetic screening on donor oocyte-recipient cycles. Am J Obstet Gynecol; In press;
  16. Paulson RJ. Preimplantation genetic screening: what is the clinical efficiency? Fertil Steril 2017;108(2):228-230
  17. McCoy RC. Mosaicism in preimplantation human embryos: When chromosomal abnormalities are the norm. Trend Genet 2017;33:448-463
  18. Adashi EY, Gleicher N. Is a blanket elective single embryo transfer policy defensible? Rambab Maimonides Med J 2017;8(2): doi 10.5041/RMMJ.10299
  19. Practice Committee of the American Society for Reproductive Medicine, Preimplantation genetic testing: a Practice Committee opinion. Fertil Steril 2008; 90:S136-143
  20. ACOG, Committee Opinion No 430. Preimplantation genetic screening for aneuploidy Obstet Gynecol 2009; 113:766-767
  21. Harton G, Braude P, Lashwood A, Schmutzler A, Traeger-Synodinos J, Wilton L, Harper JC., [10,1ESHRE PGD consortium best practice guidelines for organization of a PGD centre for PGD/preimplantation genetic screening. Hum Reprod 2011; 26:14-24
Norbert Gleicher, MD, FACOG, FACS

Norbert Gleicher, MD, FACOG, FACS

Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.

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