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

Impact of inactivated SARS-CoV-2 vaccination on embryo ploidy: a retrospective cohort study of 133 PGT-A cycles in China

“…Early pregnancy outcomes were also unaltered in subsequent euploid blastocyst transfer cycles, which provides further reassurance for vaccinated women who are planning to conceive. Ploidy status of embryos has been recognized as a principal contributing factor in implantation failure and spontaneous abortion [18]. Generally, aneuploidy is caused by meiotic errors during gametogenesis, which generates nullisomic or disomic oocytes or sperms and later leads to abnormal numerical chromosomal constitution in embryos [25].…”

“…On the contrary, mosaicism results from mitotic segregation errors in cleaving embryos after fertilization, involving a variety of mechanisms such as anaphase lag, mitotic nondisjunction, inadvertent chromosome demolition, and premature cell division before DNA duplication [26]. In IVF practice, different studies have shown that both ovarian stimulation parameters (e.g., stimulation protocol and treatment duration) and culture conditions (e.g., media type, pH, oxygen, osmolality and temperature) are closely associated with the incidence of aneuploidy and mosaicism, apart from the major influence of maternal age [18,[27][28][29].…”

“…With a specific focus on in vitro fertilization (IVF) cycles using preimplantation genetic testing for aneuploidy (PGT-A), one study further demonstrated similar euploidy rate after mRNA COVID-19 vaccination on adjusted analysis [17]. Nonetheless, it remains unclear whether inactivated SARS-CoV-2 vaccine results in any measurable influence on the status of euploidy, which is a critical indicator for both embryo quality and pregnancy chance [18].…”

Genetic testing of products of conception in recurrent pregnancy loss evaluation

“…In contrast, PGT-A improved the ongoing pregnancy rate per embryo transfer in patients between 35 and 40 years of age with at least two blastocysts available for biopsy (Munne et al, 2019), showing a potential benefit of PGT-A in this subgroup of patients. However, miscarriage rates per transfer were similar (approximately 10%), irrespective of female age, in both the PGT-A arm (11.2% at <35 years, 8.2% at ≥35 years) and the control arm (8.3% at <35 years, 11.0% at ≥35 years) (Munne et al, 2019), Consequently, the current available evidence and societies' guidelines do not support the routine use of PGT-A in all IVF cycles or in patients with unexplained RPL (Chan et al, 2020;Cornelisse et al, 2020;Dahdouh, 2021; Practice Committees of the American Society for Reproductive Medicine and the Society for Assisted Reproductive Technology, 2018;ACOG Committee, 2020). More data from a current ongoing multicentre RCT are needed to clarify the role of PGT-A in the RPL population (http://clinicaltrials.gov/show/ NCT03214185) (Lei et al, 2020).…”

The number of prior pregnancy losses does not impact euploidy rates in young patients with idiopathic recurrent pregnancy loss

“…Furthermore, in a recently published Society for Assisted Reproductive Technology Clinical Outcomes Reporting System (SART-CORS) study, the bene t of PGT-A was greater in women of advanced maternal age who suffered from RPL [16]. However, there is insu cient evidence on whether PGT-A improves the clinical outcomes in couples with idiopathic RPL [17,18]. In addition, as PGT-A is a costly treatment strategy, a detailed evaluation would determine which subgroups of patients with idiopathic RPL would bene t more from PGT-A.…”