Worldwide live births following the transfer of chromosomally "Abnormal" embryos after PGT/A: results of a worldwide web-based survey

The PGS/PGT-A controversy in IVF addressed as a formal conflict resolution analysis

PURPOSE

To use conflict resolution analysis on the conflict between proponents and opponents of preimplantation genetic testing for aneuploidy (PGT-A), previously called preimplantation genetic screening (PGS).

METHODS

Considered in conflict analysis a case study, we reviewed the English literature based on key-word searches at www.pubmed.com and www.google.com, and interviewed professional opinion leaders and other actor-representatives. This analysis was the product of a mandated externship by L.M. at the Foundation for Reproductive Medicine (FRM), as part of the Master of Science Program in Negotiations and Conflict Resolution at Columbia University, New York, NY.

RESULTS

Initially a typical difference of opinion, conflict evolved after proponents rejected studies that failed to confirm expected benefits, and authors felt demeaned by their criticism. Becoming "destructive," the conflict evolved according to Glasl's escalation model stages. Proponents became continuous attractors. Unable to produce validations for PGT-A, proponents moved goal posts through 3 stages (PGS 1.0-PGS 3.0). Ultimately concurring that pregnancy and live birth rates are unaffected, they started claiming new benefits.

CONCLUSIONS

The FRM underwrote this study as a starting tool for a conflict resolution process. A consensus building conference of stakeholders appears as of this point to represent the most promising potential intervention. The goal of such a conference should be sustainable consensus about clinical utilization of PGS/PGT-A in IVF, based on transparent and validated criteria. A potential date for such a conference is set for 2020.

Hidden in plain sight: the overstated benefits and underestimated losses of potential implantations associated with advertised PGT-A success rates

The utilization of preimplantation genetic testing for aneuploidy (PGT-A) has understandable intuitive appeal in reassuring the clinician that ‘everything possible’ has been done to assure the birth of a healthy baby. Whereas the development of the PGT-A technology is still in a relatively early stage, great strides have nevertheless been made in the understanding of the genetics of the preimplantation human embryo. The problem lies not in the progress that has been achieved, but rather, in the reality that PGT-A is being actively marketed as a mature technology. Those that market the technology overstate its benefits and underestimate the losses of potential implantations that are the consequence of the practice of PGT-A. The implication is that the PGT-A technology is accurate, has minimal errors and is ready to be applied to every case of IVF. This approach is not evidence-based. Substantial losses of potential implantations are even evident in the analysis of the numbers presented by marketing materials themselves. In order to provide accurate, evidence-based counseling for patients undergoing IVF, we need to apply an appropriate level of scientific scrutiny to the data that are available and apply PGT-A selectively to those cases in which the benefits clearly outweigh the costs.

Preliminary assessment of aneuploidy rates between the polar, mid and mural trophectoderm

The objective of this study is to compare aneuploidy rates between three distinct areas of the human trophectoderm: mural, polar and a region in between these two locations termed the ‘mid’ trophectoderm. This is a cohort study on in vitro fertilization (IVF) patients undergoing comprehensive chromosome screening at the blastocyst stage at a private IVF clinic. All embryos underwent assisted hatching on day 3 with blastocyst biopsy and comprehensive chromosome screening. Biopsied blastocysts were divided into three groups depending on which area (polar, mid, or mural) of the trophectoderm was protruding from the zona pellucida and biopsied. Aneuploidy rates were significantly higher with cells from the polar region of the trophectoderm (56.2%) compared with cells removed from the mural region of the trophectoderm (30.0%; P = 0.0243). A comparison of all three areas combined also showed a decreasing trend, but this did not reach clinical significance, polar (56.2%), mid (47.4%) and mural trophectoderm (30.0%; P = 0.1859). The non-concordance demonstrated between polar and mural trophectoderm can be attributed to biological occurrences including chromosomal mosaicism or procedural differences between embryologists.

The mechanisms and clinical application of mosaicism in preimplantation embryos

Embryos containing distinct cell lines are referred to as mosaic embryos, which are considered to be caused by mitotic errors in chromosome segregation during preimplantation development. As the accuracy and resolution of detection techniques improve, more and more mosaic embryos were identified recently. The impacts of mosaic embryos on survival and potential pregnancy outcome have been reported to be diverse in different studies. Because of the universality and clinical significance of mosaicism, it is essential to unravel the mechanisms and consequences with regard to this phenomenon in human pre- and post-implantation embryos. The purpose of this review is to explore the mechanisms, causes of mosaicism, and the development of pre- and post-implantation mosaic embryos in the light of recent emerging data, with the aim of providing new references for clinical applications.