National mosaic embryo transfer practices: a survey

Preimplantation genetic testing for aneuploidy: A Canadian Fertility and Andrology Society Guideline

“…These platforms include array comparative genomic hybridization (aCGH), single nucleotide polymorphism (SNP) array, quantitative polymerase chain reaction (qPCR), and most recently next generation sequencing (NGS). A discussion of the differences among these methods with respect to their ability to detect polyploidy, uniparental disomy, balanced translocations, and mitochondrial copy number is beyond the scope of this guideline; however, it should be noted that NGS is currently the most commonly utilized platform (Kim et al, 2018).…”

“…Some laboratories do not report mosaicism at all, considering any biopsy with greater than 40-50% abnormal cells aneuploid and anything below that threshold euploid (Kim et al, 2018;Mamas et al, 2012).…”

“…In the absence of available euploid embryos after IVF with PGT-A, many patients and physicians struggle with the decision on whether to transfer available mosaic embryos. A survey of 405 IVF clinics in the United States reported that only 36.1% of clinics that do PGT-A receive mosaicism data on their reports and of these clinics, 42.9% have transferred a mosaic embryo (Kim et al, 2018). Quantifying the outcomes of mosaic embryo transfer has been challenging not only due to the above issues with diagnostic accuracy and thresholds, but also because gold standard randomized studies comparing mosaic to unscreened or euploid embryo transfer cannot be performed due to ethical reasons.…”

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“…Rather, it offers an evidenced‐based tool for decision‐making when counseling patients dealing with mosaic embryos . Such a tool seems timely given the recent findings from a USA‐based survey of 417 respondents that indicated that 42.1% of the IVF clinics (that answered the survey) have transferred mosaic embryos, and the majority (63.2%) would opt to transfer mosaic embryos in the future . The same survey revealed that the most common PGT‐A technology utilized was next generation sequencing, which is regarded as the most sensitive technique for uncovering mosaicism.…”

Aneuploid embryo transfer: clinical policies and provider opinions at United States fertility clinics

“…For example, fewer than 30% of attendees said that they would transfer an embryo with a positive result for trisomy 21. In addition, a 2018 survey of 269 US Assisted Reproductive Technology (ART) clinic medical directors indicated that 41% of clinics have transferred a mosaic embryo and 60% said they would if asked (30). Our study expands upon this topic by surveying a larger sample of U.S. ART providers about their current clinical policies and personal opinions regarding transfer of chromosomally abnormal embryos, as well as what degree of mosaicism, if any, would affect this decision.…”