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Study Question: What is the clinical validity and utility of preconception Expanded Carrier Screening (ECS) application on the management of prospective parents?, Summary Answer: The high detection rate of at-risk couples (ARCs) and the high proportion opting for IVF/preimplantation genetic testing (PGT) treatment demonstrate the clinical utility of ECS in the preconception space in IVF and general population., What Is Known Already: About 2-4% of couples are at risk of conceiving a child with an autosomal recessive or X-linked genetic disorder. In recent years, the increasing cost-effectiveness of genetic diagnostic techniques has allowed the creation of ECS panels for the simultaneous detection of multiple recessive disorders. Comprehensive preconception genetic screening holds the potential to significantly improve couple's genetic risk assessment and reproductive planning to avoid detectable inheritable genetic offspring., Study Design, Size, Duration: A total of 3877 individuals without a family history of genetic conditions were analyzed between January 2017 and January 2020. Of the enrolled individuals, 1212 were gamete donors and 2665 were patients planning on conceiving from both the IVF and the natural conception group. From the non-donor cohort, 1133 were analyzed as individual patients, while the remaining ones were analyzed as couples, for a total of 766 couples., Participants/materials, Setting, Methods: A focused ECS panel was developed following American College of Obstetrics and Gynecology ACOG-recommended criteria (prevalence, carrier rate, severity), including highly penetrant severe childhood conditions. Couples were defined at-risk when both partners carried an autosomal recessive pathogenic/likely pathogenic variant (PLP) on the same gene or when the woman was a carrier of an X-linked PLP variant. ARC detection rate defined the clinical validity of the ECS approach. Clinical utility was evaluated by monitoring ARCs reproductive decision making., Main Results and the Role of Chance: A total of 402 individuals (10.4%) showed PLP for at least one of the genes tested. Among the 766 couples tested, 173 showed one carrier partner (22.6%), whereas 20 couples (2.6%) were found to be at increased risk. Interestingly, one ARC was identified as a result of cascade testing in the extended family of an individual carrying a pathogenic variant on the Survival Of Motor Neuron 1SMN1 gene. Of the identified ARCs, 5 (0.7%) were at risk for cystic fibrosis, 5 (0.7%) for fragile X syndrome, 4 (0.5%) for spinal muscular atrophy, 4 (0.5%) for Beta-Thalassemia/Sickle Cell Anemia, 1 (0.1%) for Smith-Lemli-Opitz Syndrome and 1 (0.1%) for Duchenne/Becker Dystrophy. Fifteen ARCs were successfully followed up from both the IVF and the natural conception groups. All of these (15/15) modified their reproductive planning by undergoing ART with Preimplantation Genetic Testing for Monogenic disease and Aneuploidies (PGT-M and PGT-A). To date, 6/15 (40%) couples completed their PGT cycle with euploid/unaffected embryos achieving a pregnancy after embryo transfer and three of them have already had an unaffected baby., Limitations, Reasons for Caution: The use of a limited panel of core gene-disease pairs represents a limitation on the research perspective as it can underestimate the rate of detectable carriers and ARCs in this cohort of prospective parents. Expanding the scope of ECS to a larger panel of conditions is becoming increasingly feasible, thanks to a persistent technological evolution and progressive cataloging of gene-disease associations., Wider Implications of the Findings: These results highlight the potential clinical validity and utility of ECS in reducing the risk of a pregnancy affected by a detectable inheritable genetic condition. The steady reduction in the costs of genetic analyses enables the expansion of monogenic testing/screening applications at the preimplantation stage, thus, providing valid decisional support and reproductive autonomy to patients, particularly in the context of IVF., Study Funding/competing Interest(s): No external funding was used for this study. A.C., M.F., S.C., M.P., L.G., and C.P. are employees of Igenomix Italy. C.S. is the head of the scientific board of Igenomix., Trial Registration Number: N/A., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: What is the potential of applying non-invasive preimplantation genetic testing (niPGT) for chromosome abnormalities in blastocysts reported with a mosaic trophectoderm (TE) biopsy?, Summary Answer: niPGT of cell-free DNA in blastocyst culture medium exhibited a good diagnostic performance in putative mosaic blastocysts., What Is Known Already: Advances in niPGT have demonstrated the potential reliability of cell-free DNA as a resource for genetic assessment, but information on mosaic embryos is scarce because the mosaicism may interfere with niPGT. In addition, the high incidence of mosaicism reported in the context of PGT and the viability of mosaic blastocysts raise questions about whether mosaicism really exists., Study Design, Size, Duration: The study was performed between May 2020 and July 2020. First, clinical data collected by a single-center over a 6-year period on PGT for chromosome aneuploidies (PGT-A) or chromosomal structural rearrangements (PGT-SR) were analyzed. After confirming the reliability of niPGT, 41 blastocysts classified as mosaics by trophectoderm (TE) biopsy were re-cultured. The chromosomal copy number of the blastocyst embryo (BE, the gold standard), TE re-biopsy, and corresponding cell-free DNA in the culture medium was assessed., Participants/materials, Setting, Methods: Data on patients enrolled for PGT at a single center from 2014 to 2019 were collected and the cycles with available putative mosaic blastocysts were evaluated. To verify the diagnostic validity of niPGT, eight aneuploid blastocysts were thawed and re-cultured for 14-18 h. The concordance of the niPGT diagnosis results and the whole blastocyst testing results was analyzed. Forty-one blastocysts reported as mosaics from 22 patients were included and re-cultured for 14-18 h. The genetic material of the BE, TE re-biopsy, and corresponding cell-free DNA in the culture medium was amplified using multiple annealing and looping-based amplification cycles. The karyotype data from niPGT and TE re-biopsy were compared with that from the whole blastocyst, and the efficiency of niPGT was assessed., Main Results and the Role of Chance: Data on 3738 blastocysts from 785 PGT-A or PGT-SR cycles of 677 patients were collected. According to the TE biopsy report, of the 3662 (98%) successfully amplified samples, 24 (0.6%) yielded no results, 849 (23.2%) were euploid, 2245 (61.3%) were aneuploid, and 544 (14.9%) were mosaic. Sixty patients without euploid blastocysts opted for a single mosaic blastocyst transfer, and 30 (50%) of them obtained a clinical pregnancy. With the BE chromosome copy number as the gold standard, niPGT and TE re-biopsy showed reliable detection ability and diagnostic efficiency in eight putative aneuploid blastocysts. Of the 41 putative mosaic blastocysts re-cultured and re-tested, 35 (85.4%) showed euploid BE results. All but two of the blastocysts previously diagnosed with segmental chromosomal mosaic were actually euploid. In addition, all blastocysts previously classified as low degree (20-50%) mosaics were identified as euploid by BE PGT, whereas four of the six putative high degree (50-80%) mosaic blastocysts showed chromosomal abnormalities. The raw concordance rates of spent culture medium (SCM) and TE re-biopsies compared with BE were 74.4% and 82%, respectively, in terms of overall ploidy and 96.2% and 97.6%, respectively, per single chromosome when considering all degree mosaic results as true positives. However, when we set a mosaicism identification threshold of 50%, the concordance rates of SCM and TE re-biopsies compared with BE were 87.2% and 85% at the overall ploidy level and 98.8% and 98.3% at the chromosomal level, respectively. At the full ploidy level, the sensitivity and false negative rates for niPGT were 100% and 0, respectively. After adjustment of the threshold for mosaicism, the specificity of niPGT increased from 69.7% to 84.8% in terms of overall ploidy and from 96.1% to 98.9% at the chromosomal level., Limitations, Reasons for Caution: The primary limitation of this study is the small sample size, which decreases the strength of our conclusions. If possible, identifying the clinical outcome of niPGT on reassessed mosaic blastocysts would be further progress in this field., Wider Implications of the Findings: This study is the first to explore the practicability of niPGT in diagnostic reassessment of putative mosaicism. The present study provides a novel opportunity for patients with only mosaic blastocysts and no euploid blastocysts, regardless of the technical or biological basis of mosaicism. Employing niPGT after 14-18 h of re-culturing might be a superior option for the best use of blastocysts because of its minimally invasive nature., Study Funding/competing Interest(s): This work was supported by grants from National Key Technology Research and Development Program of China (No. 2017YFC1002004), the Central Guiding the Science and Technology Development of the Local (2018080802D0081) and College Natural Science Project of Anhui Province (KJ2019A0287). There are no competing interests to declare., Trial Registration Number: N/A., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: What is the true incidence of chromosomal mosaicism in embryos analyzed by preimplantation genetic testing (PGT)., Summary Answer: The true incidence of chromosomal mosaicism is much lower than we usually surmise., What Is Known Already: In recent years, contemporary methods for chromosome analysis, along with the biopsy of more than one cell, have given rise to an increased rate of chromosomal mosaicism detection after preimplantation genetic testing for aneuploidy. However, the exorbitant incidence of mosaicism represents a dilemma and imposes restrictions on the application of PGT treatment. Concern has been raised about the possibility that the incidence of chromosomal mosaicism is overestimated and quite a few of the results are false-positive errors. However, studies verifying the diagnosis of chromosomal mosaicism and assessing the true incidence of chromosomal mosaicism are limited., Study Design, Size, Duration: A total of 1719 blastocysts from 380 patients who underwent PGT treatment were retrospectively analyzed to evaluate the typical incidence of mosaicism. Then 101 embryos donated by 70 couples were re-biopsied and dissected into three portions if available: trophectoderm (TE), inner cell mass (ICM), and the remaining portions. All the portions were tested using next-generation sequencing (NGS), and the results were compared to the original diagnosis., Participants/materials, Setting, Methods: The setting for this study was a university-affiliated center with an in-house PGT laboratory. All samples were amplified with multiple annealing and looping-based amplification cycles (MALBACs) and the NGS was carried out on a Life Technologies Ion Proton platform., Main Results and the Role of Chance: A clinical TE biopsy revealed an incidence of 11.9% for diploid-aneuploid mosaicism (DAM), 17.3% for aneuploid mosaicism (AM) and 29.1% in total. After rebiopsy, 94.1% whole-chromosome aneuploidies and 82.8% segmental-chromosome aneuploidies were confirmed in the embryos. As for the mosaic errors, only 32 (31.7%) out of 101 embryos presented with uniform chromosomal aberrations in agreement with the original biopsy results, 15 (14.8%) embryos presented with de novo chromosomal aberrations, and 54 (53.5%) embryos showed a euploid profile in all portions. Among the 32 uniform embryos, the true mosaicism was confirmed in only 4 cases, where a reciprocal chromosomal aberration was identified; 14 embryos presented with identical mosaicism, providing the moderate evidence for true mosaicism; and 14 embryos displayed uniform full aneuploidies in all portions of embryo, revealing a high-grade mosaicism or a false-negative diagnosis. Logistical regression analysis revealed that the concordance rate with ICM was associated with the type and level of mosaicism. The concordance rate of segmental-chromosome mosaicism was significantly lower than whole-chromosome mosaicism (adjusted Odds Ratio (aOR): 5.137 (1.061, 24.876), P = 0.042) and compared to DAM, the concordance rate of AM was significantly higher (aOR: 6.546 (1.354, 31.655), P = 0.019). The concordance rate also increased with increasing levels of mosaicism (P < 0.001)., Limitations, Reasons for Caution: This study was limited by a small sample size and the use of a single whole-genome amplification (WGA) method and NGS platform. These findings are only applicable to samples subjected to MALBAC amplification and Ion Proton platform, and studies involving larger sample sizes and multiple WGA methods and NGS platforms are required to prove our findings., Wider Implications of the Findings: TE biopsy is reliable to detect whole-chromosome aneuploidies, but the ability to diagnose mosaicism is doubtful. More attention should be paid to false-positive and false-negative errors in NGS-based PGT, especially for laboratories using less stringent criteria for mosaicism classification (i.e. 20-80%), which might be subject to a much higher false-positive mosaicism rate in the practice., Study Funding/competing Interest(s): This study was supported by grants from the National Key R&D Program of China (No. 2016YFC1000206-5) and the National Natural Science Foundation of China (No. 81701509)., Trial Registration Number: N/A., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Do embryos with different developmental competence exhibit different DNA methylation profiles at the blastocyst stage?, Summary Answer: We established genome-wide DNA methylome analysis for embryo trophectoderm (TE) biopsy samples and our findings demonstrated correlation of methylation profile of trophectoderm with euploidy status and with maternal age, indicating that genome-wide methylation level might be negatively correlated with embryo quality., What Is Known Already: DNA methylation is a fundamental epigenetic regulatory mechanism that affects differentiation of cells into their future lineages during pre-implantation embryo development. Currently there is no established approach available to assess the epigenetic status of the human preimplantation embryo during routine IVF treatment., Study Design, Size, Duration: In total, we collected trophectoderm biopsy samples from 30 randomly selected human blastocysts and conducted whole-genome bisulfite sequencing (WGBS) to evaluate their DNA methylation profile. Nested linear models were used to assess association between DNA methylation level and ploidy status (aneuploidy [n = 20] vs. euploidy [n = 10]), maternal age (29.4-42.5 years old), and time of blastulation (day 5 [n = 16] vs. day 6 [n = 14]), using embryo identity as a covariate., Participants/materials, Setting, Methods: TE biopsy samples were obtained and submitted to bisulfite conversion. For WGBS, whole-genome sequencing libraries were then generated from the converted genome. An average of 75 million reads were obtained for each sample, and about 63% of the reads aligned to human reference. An average of 40 million reads used for the final analysis after the unconverted reads were filtered out., Main Results and the Role of Chance: We revealed an increase of genome-wide DNA methylation level in aneuploid embryo TE biopsies compared to euploid embryos (25.4% ± 3.2% vs. 24.7% ± 3.2%, P < 0.005). We also found genome-wide DNA methylation level to be increased with the maternal age (P < 0.005). On a chromosomal scale, we found monosomic embryos have lower methylation levels on the involved chromosome while no drastic change was observed for the involved chromosome in trisomies. Additionally, we revealed that WGBS data precisely revealed the chromosome copy number variance., Limitations, Reasons for Caution: Though our results demonstrated a negative correlation of genome-wide methylation level and embryo quality, further WGBS analysis on a greater number of embryos and specific investigation of its correlation with implantation and live birth are needed before any practical use of this approach for evaluation of embryo competence., Wider Implications of the Findings: This study revealed a change in genome-wide DNA methylation profile among embryos with different developmental potentials, reinforcing the critical role of DNA methylation in early development., Study Funding/competing Interest(s): No external funding was received for this study. Intramural funding was provided by the Foundation for Embryonic Competence (FEC). E.S. is a consultant for and receives research funding from the Foundation for Embryonic Competence; he is also co-founder and a shareholder of ACIS LLC and coholds patent US2019/055906 issued for utilizing electrical resistance measurement for assessing cell viability and cell membrane piercing., Trial Registration Number: N/A., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Human embryos utilise an array of processes to eliminate the very high prevalence of aneuploid cells in early embryo stages. Human embryo self-correction was recently demonstrated by their ability to eliminate/expel abnormal blastomeres as cell debris/fragments. A whole genome amplification study has demonstrated that 63.6% of blastocysts expelled cell debris with abnormal chromosomal rearrangements. Moreover, 55.5% of euploid blastocysts expel aneuploid debris, strongly suggesting that the primary source of cell free DNA in culture media is expelled aneuploid blastomeres and/or their fragments. Such a substantial ability to self-correct downstream from the blastocyststage, therefore, renders any chromosomal diagnosis at the blastocyststage potentially useless, and this, unfortunately, also must particularly include non-invasive PGT-A based on cell-free DNA in spent medium. High rates of false-positive diagnoses of human embryos often lead to non-use and/or disposal of embryos with entirely normal pregnancy potential. Before adopting yet another round of unvalidated PGT-A as a routine adjunct to IVF, we here present facts that deserve to be considered., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: To what extent do characteristics of germline genome editing (GGE) determine whether the general public supports permitting the clinical use of GGE?, Summary Answer: The risk that GGE would cause congenital abnormalities had the largest effect on support for allowing GGE, followed by effectiveness of GGE, while costs, the type of application (disease or enhancement) and the effect on child well-being had moderate effects., What Is Known Already: Scientific progress on GGE has increased the urgency of resolving whether and when clinical application of GGE may be ethically acceptable. Various expert bodies have suggested that the treatment characteristics will be key in determining whether GGE is acceptable. For example, GGE with substantial risks (e.g. 15% chance of a major congenital abnormality) may be acceptable to prevent a severe disease but not to enhance non-medical characteristics or traits of an otherwise healthy embryo (e.g. eye colour or perhaps in the future more complex traits, such as intelligence). While experts have called for public engagement, it is unclear whether and how much the public acceptability of GGE is affected by the treatment characteristics proposed by experts., Study Design, Size, Duration: The vignette-based survey was disseminated in 2018 among 1857 members of the Dutch general public. An online research panel was used to recruit a sample representing the adult Dutch general public., Participants/materials, Setting, Methods: A literature review identified the key treatment characteristics of GGE: the effect on the well-being of the future child, use for disease or enhancement, risks for the future child, effectiveness (here defined as the chance of a live birth, assuming that if the GGE was not successful, the embryo would not be transferred), cost and availability of alternative treatments/procedures to prevent the genetic disease or provide enhancement (i.e. preimplantation genetic testing (PGT)), respectively. For each treatment characteristic, 2-3 levels were defined to realistically represent GGE and its current alternatives, donor gametes and ICSI with PGT. Twelve vignettes were created by fractional factorial design. A multinominal logit model assessed how much each treatment characteristic affected participants' choices., Main Results and the Role of Chance: The 1136 respondents (response rate 61%) were representative of the Dutch adult population in several demographics. Respondents were between 18 and 89 years of age. When no alternative treatment/procedure is available, the risk that GGE would cause (other) congenital abnormalities had the largest effect on whether the Dutch public supported allowing GGE (coefficient = -3.07), followed by effectiveness (coefficient = 2.03). Costs (covered by national insurance, coefficient = -1.14), the type of application (disease or enhancement; coefficient = -1.07), and the effect on child well-being (coefficient = 0.97) had similar effects on whether GGE should be allowed. If an alternative treatment/procedure (e.g. PGT) was available, participants were not categorically opposed to GGE, however, they were strongly opposed to using GGE for enhancement (coefficient = -3.37). The general acceptability of GGE was higher than participants' willingness to personally use it (P < 0.001). When participants considered whether they would personally use GGE, the type of application (disease or enhancement) was more important, whereas effectiveness and costs (covered by national insurance) were less important than when they considered whether GGE should be allowed. Participants who were male, younger and had lower incomes were more likely to allow GGE when no alternative treatment/procedure is available., Limitations, Reasons for Caution: Some (e.g. ethnic, religious) minorities were not well represented. To limit complexity, not all characteristics of GGE could be included (e.g. out-of-pocket costs), therefore, the views gathered from the vignettes reflect only the choices presented to the respondents. The non-included characteristics could be connected to and alter the importance of the studied characteristics. This would affect how closely the reported coefficients reflect 'real-life' importance., Wider Implications of the Findings: This study is the first to quantify the substantial impact of GGE's effectiveness, costs (covered by national insurance), and effect on child well-being on whether the public considered GGE acceptable. In general, the participants were strikingly risk-averse, in that they weighed the risks of GGE more heavily than its benefits. Furthermore, although only a single study in one country, the results suggests that-if sufficiently safe and effective-the public may approve of using GGE (presumably combined with PGT) instead of solely PGT to prevent passing on a disease. The reported public views can serve as input for future consideration of the ethics and governance of GGE., Study Funding/competing Interest(s): Young Academy of the Royal Dutch Academy of Sciences (UPS/RB/745), Alliance Grant of the Amsterdam Reproduction and Development Research Institute (2017-170116) and National Institutes of Health Intramural Research Programme. No competing interests., Trial Registration Number: N/A., (Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology 2020. This work is written by US Government employees and is in the public domain in the US.)

Study Question: Can whole genome sequencing (WGS) offer a relatively cost-effective approach for embryonic genome-wide haplotyping and preimplantation genetic testing (PGT) for monogenic disorders (PGT-M), aneuploidy (PGT-A) and structural rearrangements (PGT-SR)?, Summary Answer: Reliable genome-wide haplotyping, PGT-M, PGT-A and PGT-SR could be performed by WGS with 10× depth of parental and 4× depth of embryonic sequencing data., What Is Known Already: Reduced representation genome sequencing with a genome-wide next-generation sequencing haplarithmisis-based solution has been verified as a generic approach for automated haplotyping and comprehensive PGT. Several low-depth massively parallel sequencing (MPS)-based methods for haplotyping and comprehensive PGT have been developed. However, an additional family member, such as a sibling, or a proband, is required for PGT-M haplotyping using low-depth MPS methods., Study Design, Size, Duration: In this study, 10 families that had undergone traditional IVF-PGT and 53 embryos, including 13 embryos from two PGT-SR families and 40 embryos from eight PGT-M families, were included to evaluate a WGS-based method. There were 24 blastomeres and 29 blastocysts in total. All embryos were used for PGT-A. Karyomapping validated the WGS results. Clinical outcomes of the 10 families were evaluated., Participants/materials, Setting, Methods: A blastomere or a few trophectoderm cells from the blastocyst were biopsied, and multiple displacement amplification (MDA) was performed. MDA DNA and bulk DNA of family members were used for library construction. Libraries were sequenced, and data analysis, including haplotype inheritance deduction for PGT-M and PGT-SR and read-count analysis for PGT-A, was performed using an in-house pipeline. Haplotyping with a proband and parent-only haplotyping without additional family members were performed to assess the WGS methodology. Concordance analysis between the WGS results and traditional PGT methods was performed., Main Results and the Role of Chance: For the 40 PGT-M and 53 PGT-A embryos, 100% concordance between the WGS and single-nucleotide polymorphism (SNP)-array results was observed, regardless of whether additional family members or a proband was included for PGT-M haplotyping. For the 13 embryos from the two PGT-SR families, the embryonic balanced translocation was detected and 100% concordance between WGS and MicroSeq with PCR-seq was demonstrated., Limitations, Reasons for Caution: The number of samples in this study was limited. In some cases, the reference embryo for PGT-M or PGT-SR parent-only haplotyping was not available owing to failed direct genotyping., Wider Implications of the Findings: WGS-based PGT-A, PGT-M and PGT-SR offered a comprehensive PGT approach for haplotyping without the requirement for additional family members. It provided an improved complementary method to PGT methodologies, such as low-depth MPS- and SNP array-based methods., Study Funding/competing Interest(s): This research was supported by the research grant from the National Key R&D Program of China (2018YFC0910201 and 2018YFC1004900), the Guangdong province science and technology project of China (2019B020226001), the Shenzhen Birth Defect Screening Project Lab (JZF No. [2016] 750) and the Shenzhen Municipal Government of China (JCYJ20170412152854656). This work was also supported by the National Natural Science Foundation of China (81771638, 81901495 and 81971344), the National Key R&D Program of China (2018YFC1004901 and 2016YFC0905103), the Shanghai Sailing Program (18YF1424800), the Shanghai Municipal Commission of Science and Technology Program (15411964000) and the Shanghai 'Rising Stars of Medical Talent' Youth Development Program Clinical Laboratory Practitioners Program (201972). The authors declare no competing interests., Trial Registration Number: N/A., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Questions continue to be raised regarding the benefit of genetic assessment of embryos prior to transfer in IVF, specifically with regards to preimplantation genetic testing for aneuploidy (PGT-A). To evaluate and quantify these concerns, we appraised the most recent (2012-2019) randomized controlled trials on the topic. Only two of these six studies listed cumulative live birth rates per started cycle, with both eliciting a statistically non-significant result. This article describes the concern that a focus on results from the first embryo transfer compared to cumulative outcomes falsely construes PGT-A as having superior outcomes, whilst its true benefit is not confirmed, and it cannot actually improve the true pregnancy outcome of an embryo pool., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Does preimplantation genetic testing for aneuploidy (PGT-A) increase the likelihood of live birth among women undergoing autologous IVF who have fertilized embryos?, Summary Answer: PGT-A is associated with a greater probability of live birth among women 35 years old and older who are undergoing IVF., What Is Known Already: Previous studies evaluating the association between PGT-A and the incidence of live birth may be prone to confounding by indication, as women whose embryos undergo PGT-A may have a lower probability of live birth due to other factors associated with their increased risk of aneuploidy (e.g. advancing age, history of miscarriage). Propensity score matching can reduce bias where strong confounding by indication is expected., Study Design, Size, Duration: We conducted a retrospective cohort study utilizing data from women who underwent autologous IVF treatment, had their first oocyte retrieval at our institution from 1 January 2011 through 31 October 2017 and had fertilized embryos from this retrieval. If a woman elected to use PGT-A, all good quality embryos (defined as an embryo between Stages 3 and 6 with Grade A or B inner or outer cell mass) were tested. We only evaluated cycles associated with the first oocyte retrieval in this analysis., Participants/materials, Setting, Methods: Our analytic cohort included 8227 women. We used multivariable logistic regression to calculate a propensity score for PGT-A based on relevant demographic and clinical factors available to the IVF provider at the time of PGT-A or embryo transfer. We used the propensity score to match women who did and did not utilize PGT-A in a 1:1 ratio. We then used log-binomial regression to compare the cumulative incidence of embryo transfer, clinical pregnancy, miscarriage and live birth between women who did and did not utilize PGT-A. Because the risk of aneuploidy increases with age, we repeated these analyses among women <35, 35-37 and ≥38 years old based on the Society for Assisted Reproductive Technology's standards., Main Results and the Role of Chance: Overall, women with fertilized embryos who used PGT-A were significantly less likely to have an embryo transfer (risk ratios (RR): 0.78; 95% CI: 0.73, 0.82) but were more likely to have a cycle that resulted in a clinical pregnancy (RR: 1.15; 95% CI: 1.04, 1.28) and live birth (RR: 1.21; 95% CI: 1.08, 1.35) than women who did not use PGT-A. Among women aged ≥38 years, those who used PGT-A were 67% (RR: 1.67; 95% CI: 1.31, 2.13) more likely to have a live birth than women who did not use PGT-A. Among women aged 35-37 years, those who used PGT-A were also more likely to have a live birth (RR: 1.27; 95% CI: 1.05, 1.54) than women who did not use PGT-A. In contrast, women <35 years old who used PGT-A were as likely to have a live birth (RR: 0.91; 95% CI: 0.78, 1.06) as women <35 years old who did not use PGT-A., Limitations, Reasons for Caution: We were unable to abstract several potential confounding variables from patients' records (e.g. anti-Mullerian hormone levels and prior IVF treatment), which may have resulted in residual confounding. Additionally, by restricting our analyses to cycles associated with the first oocyte retrieval, we were unable to estimate the cumulative incidence of live birth over multiple oocyte retrieval cycles., Wider Implications of the Findings: Women aged 35 years or older are likely to benefit from PGT-A. Larger studies might identify additional subgroups of women who might benefit from PGT-A., Study Funding/competing Interest(s): No funding was received for this study. D.S. reports that he is a member of the Cooper Surgical Advisory Board. The other authors report no conflicts of interest., Trial Registration Number: N/A., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Is there a difference in level of decision regret following IVF treatment between those who choose to complete or not complete preimplantation genetic testing for aneuploidy [PGT-A]?, Summary Answer: Approximately one-third of the participants expressed moderate to severe regret (MSR) following their decision to either complete or not complete PGT-A; notably, decision regret was higher in those who chose not to complete PGT-A, primarily driven by significantly higher regret scores in those that experienced a miscarriage after not testing., What Is Known Already: Previous research has found that 39% of participants who completed PGT-A expressed some degree of decision regret and that negative clinical outcomes, such as lack of euploid embryos, negative pregnancy test or miscarriage, were associated with a higher level of decision regret. To date, there are no published studies assessing the possible disparity in decision regret surrounding PGT-A in a population of IVF patients that either chose to pursue PGT-A or not., Study Design, Size, Duration: An anonymous online survey was distributed to 1583 patients who underwent IVF with or without PGT-A at a single university institution between January 2016 and December 2017. In total, 335 women accessed the survey, 220 met eligibility criteria and 130 completed the full study survey. Six participants were excluded due to refusal of medical record review, and nine participants were excluded after record review due to not meeting eligibility based on cycle start date or completing only embryo banking without attempting transfer. One hundred and fifteen participants were included in the final analysis., Participants/materials, Setting, Methods: Of the 115 participants included, 55 (48%) completed PGT-A and 60 (52%) did not complete PGT-A. The online survey included four sections: Demographics; Perceptions about PGT-A risks and benefits [scale from 0 (absolutely not true) to 100 (absolutely true)]; Decision-making factors [scale from 0 (not important) to 100 (very important)]; and Brehaut Decision Regret Scale [DRS] [range 0-100, with >25 indicating MSR]. A retrospective chart review was conducted to confirm study eligibility and collect cumulative clinical outcomes of consenting participants who completed the survey., Main Results and the Role of Chance: Demographics of the PGT-A and no PGT-A cohorts were similar, with the majority of respondents being Caucasian or Asian, unaffiliated with any religion and with a graduate or professional degree. The two groups differed significantly in mean age, with the PGT-A group being slightly older (mean ± SD: 37 ± 3.7 versus 36 ± 3.4; P = 0.048), and in rate of miscarriages, with fewer participants in the PGT-A cohort experiencing a miscarriage (5% versus 22%; P = 0.012). The majority of participants in both PGT-A and no PGT-A cohorts strongly believed in the purported benefits of PGT-A, including that it decreases the risk of birth defects (median 82 versus 77; P = 0.046), improves the chances of having a healthy baby (median 89 versus 74; P = 0.002) and selects the best embryo for transfer (median 85 versus 80; P = 0.049). When asked to report their motivating factors for decision-making, both groups cited physician counseling as important (median 70 versus 71; P = 0.671); however, the PGT-A cohort was more strongly motivated by a desire to not transfer abnormal embryos (median 84 versus 53; P = 0.0001). Comparison of DRS score between those who did or did not undergo PGT-A showed significantly higher median DRS score after not completing PGT-A (median 15 versus 0; P = 0.013). There was a significantly higher proportion of participants who did not complete PGT-A that expressed mild (36% versus 16%) and MSR (32% versus 24%) compared to those who completed PGT-A (χ2 = 9.03, df = 2; P = 0.011). Sub-group analyses of DRS scores by outcomes of clinical pregnancy, miscarriage and live birth revealed that the higher DRS score in those not completing PGT-A was driven by a large increase in regret noted by those with history of a miscarriage (median 45 versus 0; P = 0.018). Multivariate logistic regression modeling found no evidence that any specific demographic factor, clinical outcome or perception/motivation surrounding PGT-A was independently predictive of increased risk for MSR., Limitations, Reasons for Caution: The retrospective nature of data collection incurs the possibility of sampling and recall bias. As only 59% of eligible respondents completed the full survey, it is possible that mainly those with very positive or negative sentiments following treatment felt compelled to complete their response. This bias, however, would apply to the whole of the population, and not simply to those who did or did not complete PGT-A., Wider Implications of the Findings: The proportion of participants expressing any degree of decision regret in this PGT-A cohort was 40%, which is comparable to that shown in prior research. This study adds to prior data by also assessing decision regret experienced by those who went through IVF without PGT-A, and showed that 68% expressed some level of regret with their decision-making. These results should not be interpreted to mean that all patients should opt for PGT-A to pre-emptively mitigate their risk of regret. Instead, it suggests that drivers of decision regret are likely multifactorial and unique to the experience of one's personal expectations regarding PGT-A, motivations for pursuing or not pursuing it and resultant clinical outcome. Highlighting the complex nature of regret, these data should encourage physicians to more carefully consider individual patient values toward risk-taking or risk-averse behavior, as well as their own positions regarding PGT-A. Until there are clear recommendations regarding utilization of PGT-A, a strong collaboration between physicians and genetic counselors is recommended to educate patients on the risks and potential benefits of PGT-A in a balanced and individualized manner., Study Funding/competing Interest(s): No funding was utilized for study completion and the authors have no competing interests., Trial Registration Number: N/A., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Has the number of preimplantation genetic testing (PGT) cycles in the UK and USA changed between 2014 and 2016?, Summary Answer: From 2014 to 2016, the number of PGT cycles in the UK has remained the same at just under 2% but in the USA has increased from 13% to 27%., What Is Known Already: PGT was introduced as a treatment option for couples at risk of transmitting a known genetic or chromosomal abnormality to their child. This technology has also been applied as an embryo selection tool in the hope of increasing live birth rates per transfer. ART cycles are monitored in the UK by the Human Fertilisation and Embryology Authority (HFEA) and in the USA by the Society for Assisted Reproductive Technology (SART). Globally, data are monitored via the ESHRE PGT Consortium., Study Design, Size, Duration: This cross-sectional study used the HFEA and SART databases to analyse PGT cycle data and make comparisons with IVF data to examine the success of and changes in patient treatment pathways. Both data sets were analysed from 2014 to 2016. The UK data included 3385 PGT cycles and the USA data included 94 935 PGT cycles., Participants/materials, Setting, Methods: Following an extensive review of both databases, filters were applied to analyse the data. An assessment of limitations of each database was also undertaken, taking into account data collection by the ESHRE PGT Consortium. In the UK and USA, the publicly available information from these datasets cannot be separated into different indications., Main Results and the Role of Chance: The proportion of PGT cycles as a total of ART procedures has remained the same in the UK but increased annually in the USA from 13% to 27%. Between 2014 and 2016 inclusive, 3385 PGT cycles have been performed in the UK, resulting in 1074 PGT babies being born. In the USA 94 935 PGT cycles have been performed, resulting in 26 822 babies being born. This gave a success rate per egg collection for PGT of 32% for the UK and 28% for the USA. Analysis of the data by maternal age shows very different patient populations between the UK and USA. These differences may be related to the way PGT is funded in the UK and USA and the lack of HFEA support for PGT for aneuploidy., Limitations, Reasons for Caution: Data reported by the HFEA and SART have different limitations. As undertaken by the ESHRE PGT Consortium, both data sets should separate PGT data by indication. Although the HFEA collects data from all IVF clinics in the UK, SART data only represent 83% of clinics in the USA., Wider Implications of the Findings: Worldwide, a consistent reporting scheme is required in which success rates can convey the effectiveness of PGT approaches for all indications., Study Funding/competing Interest(s): No specific funding was obtained and there are no competing interests to declare that are directly related to this project. Joyce Harper is the director of the Embryology and PGD Academy, which offers education in these fields., (© The Author(s) 2020. Published by Oxford University Press.)

Study Question: Is de novo segmental aneuploidy (SA) a biological event or an artifact that is erroneously interpreted as partial chromosome imbalance?, Summary Answer: The detection of de novo SA in sequential biopsies of preimplantation embryos supports the biological nature of SA., What Is Known Already: Although some SAs are detected in oocytes and in blastocysts, the highest incidence is observed in cleavage-stage embryos. Based on these findings, we can postulate that the majority of cells affected by SAs are eliminated by apoptosis or that affected embryos mainly undergo developmental arrest., Study Design, Size, Duration: This retrospective study includes 342 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed between January 2014 and December 2018. Chromosome analysis was performed on 331 oocytes, 886 cleavage-stage embryos and 570 blastocysts (n = 1787). From 268 expanded blastocysts, the blastocoelic fluid (BF) was also analyzed (resulting in 2025 samples in total). In cases of SAs involving loss or gain in excess of 15 Mb, embryos were not considered for transfer and sequential biopsies were performed at following stages. This resulted in 66 sets where the initial diagnosis of SAs (4 made in polar bodies, 25 in blastomeres and 37 in trophectoderm (TE) cells) was followed up., Participants/materials, Setting, Methods: A total of 2082 samples (2025 + 27 whole embryos) were processed by whole genome amplification followed by array comparative genomic hybridization., Main Results and the Role of Chance: The incidence of SAs was 6.3% in oocytes, increased to 16.6% in cleavage-stage embryos (P < 0.001) and decreased to 11.2% in blastocysts (P < 0.025 versus oocytes; P < 0.01 versus cleavage-stage embryos). The highest incidence of SAs was found in BFs (26.1%, P < 0.001). The analysis of 66 sets of sequential biopsies revealed that the initial finding was confirmed in all following samples from 39 sets (59.1% full concordance). In 12 additional sets, SAs were detected in some samples while in others the interested chromosome had full aneuploidy (18.2%). In three more sets, there was a partial concordance with the initial diagnosis in some samples, but in all TE samples the interested chromosome was clearly euploid (4.5%). In the remaining 12 sets, the initial SA was not confirmed at any stage and the corresponding chromosomes were euploid (18.2% no concordance). The pattern of concordance was not affected by the number of SAs in the original biopsy (single, double or complex) or by the absence or presence of concomitant aneuploidies for full chromosomes., Limitations, Reasons for Caution: Chromosome analyses were performed on biopsies that might not be representative of the true constitution of the embryo itself due to the occurrence of mosaicism., Wider Implications of the Findings: The permanence of SAs throughout the following stages of embryo development in more than half of the analyzed sets suggests for this dataset a very early origin of this type of chromosome imbalance, either at meiosis or at the first mitotic divisions. Since SAs remained in full concordance with the initial diagnosis until the blastocyst stage, a corrective mechanism seems not to be in place. In the remaining cases, it is likely that, as for full chromosome aneuploidy, mosaicism derived from mitotic errors could have occurred. In following cell divisions, euploid cell lines could prevail preserving the embryo chances of implantation. Due to the scarcity of data available, the transfer of embryos with SAs should be strictly followed up to establish possible clinical consequences related to this condition., Study Funding/competing Interest(s): No specific funding was obtained. There are no conflicts of interest., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

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., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Study Question: Is it possible to haplotype parents using parental siblings to leverage preimplantation genetic testing (PGT) for monogenic diseases and aneuploidy (comprehensive PGT) by genome-wide haplotyping?, Summary Answer: We imputed identity-by-state (IBS) sharing of parental siblings to phase parental genotypes., What Is Known Already: Genome-wide haplotyping of preimplantation embryos is being implemented as a generic approach for genetic diagnosis of inherited single-gene disorders. To enable the phasing of genotypes into haplotypes, genotyping the direct family members of the prospective parent carrying the mutation is required. Current approaches require genotypes of either (i) both or one of the parents of the affected prospective parent or (ii) an affected or an unaffected child of the couple. However, this approach cannot be used when parents or children are not attainable, prompting an investigation into alternative phasing options., Study Design, Size, Duration: This is a retrospective validation study, which applied IBS-based phasing of parental haplotypes in 56 embryos derived from 12 PGT families. Genome-wide haplotypes and copy number profiles generated for each embryo using the new phasing approach were compared with the reference PGT method to evaluate the diagnostic concordance., Participants/materials, Setting, Methods: This study included 12 couples with a known hereditary genetic disorder, participating in the comprehensive PGT program and with at least one parental sibling available (e.g. brother and/or sister). Genotyping data from both prospective parents and the parental sibling(s) were used to perform IBS-based phasing and to trace the disease-associated alleles. The outcome of the IBS-based PGT was compared with the results of the clinically implemented reference haplotyping-based PGT method., Main Results and the Role of Chance: IBS-based haplotyping was performed for 12 PGT families. In accordance with the theoretical prediction of allele sharing between sibling pairs, 6 out of 12 (50%) couples or 23 out of 56 embryos could be phased using parental siblings. In families where phasing was possible, haplotype calling in the locus of interest was 100% concordant between the reference PGT method and IBS-based approach using parental siblings., Large Scale Data: N/A., Limitations, Reasons for Caution: Phasing of parental haplotypes will only be possible when the disease locus lies in an informative region (categorized as IBS1). Phasing prospective parents using relatives with reduced genetic relatedness as a reference (e.g. siblings) decreases the size and the occurrence of informative IBS1 regions, necessary for haplotype calling. By including more than one extended family member, the chance of obtaining IBS1 coverage in the interrogated locus can be increased. A pre-PGT work-up can define whether the carrier couple could benefit from this approach., Wider Implications of the Findings: Phasing by relatives extends the potential of comprehensive PGT, since it allows the inclusion of couples who do not have access to the standard phasing references, such as parents or offspring., Study Funding/competing Interest(s): The study was funded by the KU Leuven grant (C14/18/092), Research Foundation Flanders (FWO; GA09311N), Horizon 2020 innovation programme (WIDENLIFE, 692065) and Agilent Technologies. J.R.V., T.V. and M.Z.E. are co-inventors of a patent ZL910050-PCT/EP2011/060211-WO/2011/157846 'Methods for haplotyping single-cells' and ZL913096-PCT/EP2014/068315-WO/2015/028576 'Haplotyping and copy number typing using polymorphic variant allelic frequencies' licensed to Agilent Technologies. The other authors have no conflict of interest to declare., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Mosaic embryos have the potential to implant and develop into healthy babies. The transfer of mosaic embryos is now considered to be a possible option for women undergoing ART with preimplantation genetic testing for aneuploidies and in the absence of euploid embryos, particularly those with diminished ovarian reserve and/or advanced maternal age. It can aid in avoiding the discard of potentially viable embryos, which might otherwise result in healthy babies. In over 500 studies on mosaicism, there have been no reports of mosaicism in babies born following the transfer of mosaic embryos. Here, we present a case report of a 39-year-old woman with diminished ovarian reserve with only one blastocyst available for trophectoderm biopsy. The transfer of the embryo, which showed 35% mosaicism of monosomy 2, resulted in pregnancy. Amniocentesis revealed a mosaic trisomic mos46,XX(98)/47,XX,+2(2) karyotype. There were no pathological findings in detailed ultrasonography, and the fetus showed a normal fetal growth with no evidence of intrauterine growth retardation. A healthy female baby was born at Week 37. The peripheral blood chromosome analysis validated with fluorescence in situ hybridization showed 2% mosaic monosomy 2 [mos45,XX,-2(2)/46,XX(98)]. This is the first reported case of true fetal mosaicism resulting in a live birth following the transfer of a known mosaic embryo. Worldwide, prenatal diagnosis has shown the depletion of mosaicism in embryos transferred after they have been reported as mosaics. Our case demonstrates the need for close prenatal monitoring and diagnosis by early amniocentesis, preferably at >14 weeks gestation., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.)

Study Question: Is it cost-effective to use in vitro fertilisation and preimplantation genetic testing of monogenic defects (IVT/PGT-M) to prevent transmission of BRCA1/2 mutations to second-generation new births in comparison with naturally conceived births?, Summary Answer: In this cost-effectiveness analysis, we found that IVF/PGT-M is cost-effective for BRCA1 and BRCA2 mutation carriers if using a willingness to pay of $50 000 per quality-adjusted life-year (QALY)., What Is Known Already: Carriers of a BRCA1 or BRCA2 mutation have a significantly increased risk of several types of cancer throughout their lifetime. The cost of risk reduction, screening and treatment of cancer in this population is high. In addition, there is a 50% chance of passing on this genetic mutation to each child. One option to avoid transmission of an inherited deleterious gene to one's offspring involves in vitro fertilisation with preimplantation genetic testing., Study Design, Size, Duration: We implemented a state transition model comparing the healthcare impact of a cohort of healthy children born after IVF/PGT-M, who have a population risk of developing cancer, to a cohort of naturally conceived live-births, half of whom are carriers of the BRCA mutation. Transition probabilities are based on published sources, a lifetime horizon and a perspective of a provincial Ministry of Health in Canada., Participants/materials, Setting, Methods: The target population is the second-generation new births who have at least one parent with a known BRCA1 or BRCA2 mutation., Main Results and the Role of Chance: At a willingness-to-pay threshold of $50 000 per QALY, IVF/PGT-M is a cost-effective intervention for carriers of either BRCA mutation. For BRCA1, the incremental cost-effectiveness ratio (ICER) for IVF/PGT-M is $14 242/QALY. For BRCA2, the ICER of intervention is $12 893/QALY. Probabilistic sensitivity analysis results show that IVF/PGT-M has a 98.4 and 97.3% chance of being cost-effective for BRCA1 and BRCA2 mutation carriers, respectively, at the $50 000/QALY threshold., Limitations, Reasons for Caution: Our model did not include the short-term negative effect of IVF/PGT-M on the woman's quality of life; in addition, our model did not consider any ethical issues related to post-implantation genetic testing., Wider Implications of the Findings: In countries in which the healthcare of a large segment of the population is covered by a single payer system such as the government, it would be cost-effective for that payer to cover the cost of IVF/PGT-M for couples in which one member has a BRCA mutation, in order to avoid the future costs and disutility of managing offspring with an inherited BRCA mutation., Study Funding/competing Interest(s): Dr Wong's research program was supported by the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council (NSERC), the Canadian Liver Foundation and an Ontario Ministry of Research, Innovation and Science Early Researcher Award. All authors declared no conflict of interests., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Study Question: Can preimplantation genetic testing for aneuploidy (PGT-A) improve the live birth rate and reduce the miscarriage rate in patients with recurrent pregnancy loss (RPL) caused by an abnormal embryonic karyotype and recurrent implantation failure (RIF)?, Summary Answer: PGT-A could not improve the live births per patient nor reduce the rate of miscarriage, in both groups., What Is Known Already: PGT-A use has steadily increased worldwide. However, only a few limited studies have shown that it improves the live birth rate in selected populations in that the prognosis has been good. Such studies have excluded patients with RPL and RIF. In addition, several studies have failed to demonstrate any benefit at all. PGT-A was reported to be without advantage in patients with unexplained RPL whose embryonic karyotype had not been analysed. The efficacy of PGT-A should be examined by focusing on patients whose previous products of conception (POC) have been aneuploid, because the frequencies of abnormal and normal embryonic karyotypes have been reported as 40-50% and 5-25% in patients with RPL, respectively., Study Design, Size, Duration: A multi-centre, prospective pilot study was conducted from January 2017 to June 2018. A total of 171 patients were recruited for the study: an RPL group, including 41 and 38 patients treated respectively with and without PGT-A, and an RIF group, including 42 and 50 patients treated respectively with and without PGT-A. At least 10 women in each age group (35-36, 37-38, 39-40 or 41-42 years) were selected for PGT-A groups., Participants/materials, Setting, Methods: All patients and controls had received IVF-ET for infertility. Patients in the RPL group had had two or more miscarriages, and at least one case of aneuploidy had been ascertained through prior POC testing. No pregnancies had occurred in the RIF group, even after at least three embryo transfers. Trophectoderm biopsy and array comparative genomic hybridisation (aCGH) were used for PGT-A. The live birth rate of PGT-A and non-PGT-A patients was compared after the development of blastocysts from up to two oocyte retrievals and a single blastocyst transfer. The miscarriage rate and the frequency of euploidy, trisomy and monosomy in the blastocysts were noted., Main Result and the Role of Chance: There were no significant differences in the live birth rates per patient given or not given PGT-A: 26.8 versus 21.1% in the RPL group and 35.7 versus 26.0% in the RIF group, respectively. There were also no differences in the miscarriage rates per clinical pregnancies given or not given PGT-A: 14.3 versus 20.0% in the RPL group and 11.8 versus 0% in the RIF group, respectively. However, PGT-A improved the live birth rate per embryo transfer procedure in both the RPL (52.4 vs 21.6%, adjusted OR 3.89; 95% CI 1.16-13.1) and RIF groups (62.5 vs 31.7%, adjusted OR 3.75; 95% CI 1.28-10.95). Additionally, PGT-A was shown to reduce biochemical pregnancy loss per biochemical pregnancy: 12.5 and 45.0%, adjusted OR 0.14; 95% CI 0.02-0.85 in the RPL group and 10.5 and 40.9%, adjusted OR 0.17; 95% CI 0.03-0.92 in the RIF group. There was no difference in the distribution of genetic abnormalities between RPL and RIF patients, although double trisomy tended to be more frequent in RPL patients., Limitations, Reasons for Caution: The sample size was too small to find any significant advantage for improving the live birth rate and reducing the clinical miscarriage rate per patient. Further study is necessary., Wider Implication of the Findings: A large portion of pregnancy losses in the RPL group might be due to aneuploidy, since PGT-A reduced the overall incidence of pregnancy loss in these patients. Although PGT-A did not improve the live birth rate per patient, it did have the advantage of reducing the number of embryo transfers required to achieve a similar number live births compared with those not undergoing PGT-A., Study Funding/competing Interest(s): This study was supported by the Japan Society of Obstetrics and Gynecology and grants from the Japanese Ministry of Education, Science, and Technology. There are no conflicts of interest to declare., Trial Registration Number: N/A., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Study Question: Which are the clinical benefits and risks of including poor-quality blastocysts (PQBs) in the cohort of biopsied embryos during a cycle with preimplantation genetic testing for aneuploidies (PGT-A)?, Summary Answer: PQBs show a worse prognosis with respect to sibling non-PQBs, but their clinical use allows an overall 2.6% increase in the number of live births (LBs) achievable after PGT-A., What Is Known Already: PQBs (

Study Question: Are meiotic segregation patterns of reciprocal translocations affected by the combined effect of chromosome type and carrier's sex?, Summary Answer: Interaction of an acrocentric chromosome (Acr-ch) involved in the translocation and sex of the carrier influences the proportion of alternate segregation for normal or balanced chromosome contents during meiotic segregation in autosomal reciprocal translocations., What Is Known Already: Carriers of reciprocal translocations are at a significantly increased risk of fertility problems due to the generation of unbalanced gametes in meiotic segregation of a quadrivalent. Previous studies have reported that meiotic segregation patterns of a quadrivalent can be affected by factors such as a carrier's sex and age and the chromosome type. However, the reported proportion of alternate segregation does not differ significantly, except in one study, and whether combined effects between these factors exist is unclear., Study Design, Size, Duration: A retrospective study of array comparative genomic hybridization (aCGH) outcome data from patients with autosomal reciprocal translocations was conducted to analyse meiotic segregation patterns and blastocyst euploidy rates. We enroled 473 couples whose embryos were tested between January 2013 and September 2016., Participants/materials, Setting, Methods: Meiotic segregation patterns of 2101 blastocysts from 243 female carriers, including 76 cases with translocations involving Acr-ch, and 230 male carriers, including 88 cases with translocations involving Acr-ch, were analysed according to chromosome type, carrier's sex and age., Main Results and the Role of Chance: In cases with translocations involving the Acr-ch subgroup, the proportion of alternate segregation (53.9 vs 33.4%, P < 0.0001) was significantly higher in male carriers than in female carriers, with the proportion of 3:1 segregation (6.8 vs 16.3%, P < 0.0001) being significantly lower. The proportions of alternate segregation were similar between sexes in cases with translocations not involving the Acr-ch subgroup. Meanwhile, in the female carrier subgroup, the proportion of alternate segregation (33.4 vs 45.2%, P < 0.001) was significantly lower and the proportion of 3:1 segregation (16.3 vs 8.2%, P < 0.001) was significantly higher in cases with translocations involving Acr-ch than in those not. In the male carrier subgroup, the proportion of alternate segregation (53.9 vs 46.9%, P = 0.031) was higher and the proportion of adjacent-1 segregation (27.1 vs 37.3%, P < 0.001) was significantly lower in cases with translocations involving Acr-ch than in those not. Carrier's age did not affect the meiotic segregation patterns. However the euploidy rates were significantly lower in couples with advanced compared to young maternal age respectively., Limitations, Reasons for Caution: Mosaic embryos were not identified using aCGH in this study. Patients with complex chromosome rearrangements and translocations involving sex chromosomes were excluded. Interchromosomal effect was not analysed., Wider Implications of the Findings: The findings of this study provide detailed information for genetic counselling of couples with autosomal reciprocal translocations on their chances of producing euploid gametes., Study Funding/competing Interest(s): This research was supported by the National Key Research and Development Program of China (2016YFC1000202); the National Natural Science Foundation of China (81671522); the Natural Science Foundation of Shandong Province in China (ZR2016HP09); and the Innovative Foundation of Reproductive Hospital Affiliated to Shandong University (20171114, 20171111). No competing interests are declared., Trial Registration Number: N/A.

The accurate genetic screening of pre-implantation embryos currently entails the use of technically challenging and biologically invasive biopsies of the human embryos. Investigating a more conservative sampling approach has emerged as a timely and desired alternative. Circulating cell-free embryonic DNA is present in the blastocoel fluid and spent culture media of blastocysts, and this has lately been sought as an attractive source of genetic information. The genetic analysis of cell-free embryonic DNA has been reported, to be useful in evaluating the genetic constitution of embryos; thus, providing a potential alternative to conventional biopsy-derived pre-implantation genetic testing (PGT). In this review, we have summarized these non-invasive alternative applications of PGT and discussed their current limitations and future clinical implications.

Study Question: Does PGD increase the risk on adverse cognitive and socio-emotional development?, Summary Answer: The cognitive and socio-emotional development in children born after PGD seems to be normal when compared to control groups., What Is Known Already: A limited number of studies with small sample sizes indicate that the cognitive and socio-emotional development of (pre)school-aged children born after either PGD or PGS seem to be comparable to those of children born after IVF/ICSI and to naturally conceived (NC) children from the general population., Study Design, Size, Duration: For this study we invited 72 5-year-old PGD children, 128 5-year-old IVF/ICSI children and 108 5-year-old NC children from families with a genetic disorder. All children were invited between January 2014 and July 2016., Participants/materials, Setting, Methods: In total, 51 PGD children, 52 IVF/ICSI children and 35 NC children underwent neuropsychological testing (WPPSI-III-NL and AWMA). The children's parent(s) and teachers filled in questionnaires evaluating children's executive functioning (Behaviour Rating Inventory of Executive Functions; BRIEF) and socio-emotional development (Child Behaviour Checklist; CBCL and Caregiver-Teacher Report Form; C-TRF)., Main Results and the Role of Chance: The mean full-scale intelligence quotient scores (P = 0.426) and performance on the AWMA Listening Span task (P = 0.873) and Spatial Span task (P = 0.458) were comparable between the three groups. Regarding socio-emotional development, the teachers' scores revealed more externalizing (P = 0.011) and total problem (P = 0.019) behaviour in PGD children than for IVF/ICSI children; both groups did not differ significantly from the NC children (P = 0.11). More children (13%) with an affected first-degree family member (mostly parent) were included in the PGD group than in the NC group. Scores in all groups fell within the normal population range and should be considered normal., Limitations, Reasons for Caution: The number of NC children from families with a genetic disorder was relatively small. Furthermore, the fathers' CBCL results were based on small samples., Wider Implications of the Findings: PGD children show levels of cognitive and socio-emotional development at 5 years that are within the normal range, despite the biopsy involved in PGD and the potential extra psychological burden associated with the presence of a genetic disorder in the family., Study Funding/competing Interest(s): This study was funded by ZonMw (70-71300-98-106). None of the authors have any competing interests to declare., Trial Registration Number: NCT02149485.

Study Question: Is the total dose of exogenous gonadotropins associated with blastocyst aneuploidy or live-birth rates in PGS cycles in Chinese women?, Summary Answer: The total dose of exogenous gonadotropins is not significantly associated with blastocyst aneuploidy or live-birth rates in PGS cycles in Chinese women., What Is Known Already: The administration of gonadotropins in ovarian stimulation leads to supraphysiological steroid concentrations compared with those seen during natural cycles. The rate of euploid blastocytes is negatively associated with female age., Study Design, Size, Duration: This is a retrospective study using anonymised data on PGS cycles performed in China from 2013 to 2017. Data from 1088 PGS cycles and 3219 embryos were analysed by array-comparative genomic hybridization (array-CGH)., Participants/materials, Setting, Methods: The study included 944 women who underwent PGS cycles with COH. All cycles were analysed by the total dose of exogenous gonadotropins (<1500, 1500-3000 and >3000 IU), patient age (<35 and ≥35 y.o.) and number of oocytes retrieved (1-5, 6-10, 11-15 and >15 oocytes)., Main Results and the Role of Chance: In the group of younger women (<35 y.o., 537 PGS cycles), the incidence of aneuploidy ranged from 36.9 to 43.4% when data was stratified by gonadotropins dose. After adjusting for confounding factors, the dose of exogenous gonadotropins was not associated with the blastocyst aneuploidy rate. Similar results were shown in the group of women with advanced maternal age (≥35 y.o., 551 PGS cycles), with no difference in the rate of blastocyst aneuploidy among different gonadotropins dose groups (<1500 IU, 58.0%; 1500-3000 IU, 59.8%; and >3000 IU, 59.8%; P = 0.86). The live-birth rates after single cryopreserved blastocyst transfers were also not significantly associated with the gonadotropins dose., Limitations, Reasons for Caution: Limitations include the retrospective study design and the heterogeneity of the included patients. Additionally, array-CGH may not be able to correctly identify mosaicism., Wider Implications of the Findings: The finding that gonadotropin dosage is not associated with embryonic aneuploidy or live-birth rates in Chinese women suggests that the high doses of gonadotropins used in ART cycles may be safe. The findings are consistent with those of prior studies in other populations., Study Funding/competing Interest(s): This study was supported by the National Natural Science Foundation of China (81671522) and National Key Research and Development Program of China (2016YFC1000202)., Trial Registration Number: N/A.

Study Question: Which is the prevalence of a 47,XXY karyotype in human blastocysts biopsied during preimplantation genetic testing for aneuploidies (PGT-A) cycles?, Summary Answer: The prevalence of a 47,XXY karyotype amongst male blastocysts without autosomal aneuploides is ~1%., What Is Known Already: The prevalence of Klinefelter syndrome is estimated as 0.1-0.2% in male newborns. However, the KS phenotype is extremely variable and there are men with a 47,XXY karyotype and less evident signs, who may go undetected. No risk factor for the 47,XXY karyotype in products of conception has been yet clearly defined, and no data are available regarding the prevalence of this karyotype among human preimplantation embryos., Study Design, Size, Duration: This multicentre cohort study involved 7549 blastocysts obtained during 2826 PGT-A cycles performed between April 2013 and September 2017 at six IVF clinics in Italy., Participants/materials, Setting, Methods: During 2826 PGT-A cycles, 7549 blastocysts underwent trophectoderm biopsy and quantitative-PCR-based comprehensive chromosomal testing to predict the karyotype of the corresponding embryos. The results were also presented according to ranges of maternal and paternal age at oocyte retrieval as well as sperm factor and blastocyst quality. Univariate and multivariate logistic regression analyses were conducted to investigate the correlation of possible confounding factors with the prevalence of 47,XXY karyotype., Main Results, the Role of Chance: Overall, 62 blastocysts were 47,XXY or had an XXY karyotype associated with autosomal aneuploidies. After exclusion of the latter, the prevalence of a 47,XXY karyotype among male blastocysts without autosomal aneuploidies was 0.9% (n = 17/1794). A significant correlation was only found for maternal age and blastocyst quality (OR: 1.20, 95% CI: 1.01-1.42; P = 0.04 and OR: 1.6, 95% CI: 1.13-2.45; P = 0.01)., Limitations, Reasons for Caution: These retrospective data have been produced based on a population of infertile couples undergoing IVF and PGT-A, and the women were mainly of advanced maternal age. Moreover, the qPCR technique is validated only to detect full-chromosome uniform aneuploidies in trophectoderm biopsies., Wider Implications of the Findings: The 0.9% prevalence of the 47,XXY karyotype among male blastocysts, when compared with the 0.1-0.2% prevalence reported in the prenatal and postnatal periods, suggests four possible scenarios that require further investigations: (i) the latter prevalence is underestimated; (ii) 47,XXY blastocysts result in a lower implantation rate than euploid embryos (estimated to be ≈50%); (iii) 47,XXY blastocysts result in a higher early miscarriage rate than euploid embryos (estimated to be ≈10%); or (iv) infertile patients of advanced maternal age and referred to IVF/PGT-A produce a higher rate of 47,XXY blastocysts., Study Funding/competing Interest(s): None., Trial Registration Number: N/A.

Study Question: Do specific factors affect the segregation patterns of a quadrivalent structure and can the quadrivalent affect genome stability during meiosis?, Summary Answer: Meiotic segregation patterns can be affected by the carrier's gender and age, location of breakpoints and chromosome type, and the quadrivalent structure can increase genome instability during meiosis., What Is Known Already: Carriers of reciprocal translocations have an increased genetic reproductive risk owing to the complex segregation patterns of a quadrivalent structure. However, the results of previous studies on the factors that affect segregation patterns seem to be contradictory, and the effect of a quadrivalent on genome stability during meiosis is unknown., Study Design, Size, Duration: We designed a retrospective study to analyze the segregation patterns of 24 chromosomes from reciprocal translocation and non-translocation patients. Data for 356 reciprocal translocation carriers and 53 patients with the risk to transmit monogenic inherited disorders (RTMIDs) undergoing PGD-single nucleotide polymorphism array analysis were collected. The study was performed between March 2014 and July 2017., Participants/materials, Setting, Methods: Segregation patterns of a quadrivalent in 1842 blastocysts from 466 assisted reproduction cycles of reciprocal translocation carriers were analyzed according to the location of chromosome breakpoints, the carrier's gender and age, and chromosome type. In addition, to analyze the effect of quadrivalent structure on genome stability, segregation products of chromosomes which are not involved in the translocation from translocation carriers were compared with those of 23 pairs of chromosomes in 318 blastocysts from 72 assisted reproduction cycles of patients with RTMIDs., Main Results and the Role of Chance: The percentage of adjacent-2 products with severe asymmetric quadrivalent was significantly higher than those with mild asymmetric quadrivalent (P = 0.020) while, in contrast, the incidence of 4:0/others was lower (P = 0.030). The frequencies of adjacent-1, adjacent-2 and 3:1 products differed between male and female carriers (P < 0.001, P = 0.015 and P = 0.001, respectively), and also for adjacent-1 and 4:0/others products in young versus older carriers (P = 0.04 and P = 0.002, respectively). In addition, adjacent-1 products of a quadrivalent with an acrocentric chromosome were significantly higher than those of a quadrivalent without an acrocentric chromosome (P = 0.001). Moreover, a quadrivalent could significantly increase the frequencies of abnormal chromosomes compared to patients with RTMIDs (P = 0.048, odds ratio (OR) = 1.43, 95% CI = 1.01-2.43), especially for the male carriers (P = 0.018, OR = 1.58, 95% CI = 1.08-2.25). In contrast, for older carriers, no difference was found in both aneuploidy and segmental anomalies compared to patients with RTMIDs., Limitations, Reasons for Caution: The study contained appropriate controls, yet the analysis was limited by a small number of control patients and embryos., Wider Implications of the Findings: Until now, there had been no definite report about the effect of quadrivalents on genome stability in reciprocal translocation carriers compared with control samples, and in the present study the large sample size ensured a detailed analysis of factors with a possible impact on segregation patterns. These data provide a better insight into the meiotic mechanisms involved in non-disjunction events in gametes from reciprocal translocation carriers. In addition, our results will help to provide each reciprocal translocation carrier couple undergoing PGD with more appropriate genetic counseling and a better understanding of the large numbers of abnormal embryos with chromosome aneuploidy., Study Funding/competing Interest(s): The research was supported by the Research Funding of Shanghai Ji Ai Genetics & IVF Institute and the authors declare a lack of competing interests in this study.

Study Question: Has PGD-HLA been successful relative to diagnostic and clinical efficacy?, Summary Answer: The diagnostic efficacy of PGD-HLA protocols was found lower in this study in comparison to published PGD-HLA protocols and to that reported for general PGD by ESHRE (78.5 vs 94.1% and vs 92.6%, respectively), while the clinical efficacy has proven very difficult to assess due to inadequate follow-up of both the ART/PGD and HSCT procedure outcomes., What Is Known Already: The first clinical cases for PGD-HLA were reported in 2001. It is now a well-established procedure, with an increasing number of cycles performed every year. However, PGD-HLA is still offered by relatively few PGD centres, the currently available data is fragmented and most reports on PGD-HLA applications are limited in number and scope. Published systematic details on methodology, diagnostic results, overall ART success and haematopoietic stem cell transplantation (HSCT) outcomes are limited, precluding an evaluation of the true clinical utility of PGD-HLA cycles., Study Design, Size, Duration: This retrospective multi-centre cohort study aimed to investigate the diagnostic and clinical efficacy of the PGD-HLA procedure and the aspects of PGD-HLA cycles influencing positive outcomes: birth of genetically suitable donor-baby (or babies) and HSCT. In April 2014, 32 PGD centres (Consortium members and non-members) with published/known PGD-HLA activity were invited to participate. Between February and September 2015, 14 centres submitted their data, through a custom-designed secure database, with unique login access for each centre. Data parameters covered all aspects of PGD-HLA cycles (ART, embryology and genetic diagnosis), donor-babies born and HSCT., Participants/materials, Setting, Methods: From 716 cycles submitted by 14 centres (performed between August 2001 and September 2015), the quality evaluation excluded 12 cycles, leaving 704, from 364 couples. The online database, based on REDCap, a free, secure, web-based data-capture application, was customized by Centre for Clinical Epidemiology and Outcomes Research (CLEO), Athens. Continuous variables are presented using mean, standard deviation, median and interquartile range, and categorical variables are presented as absolute and relative frequencies., Main Results and the Role of Chance: The data included 704 HLA-PGD cycles. Mean maternal age was 33.5 years. Most couples (81.3%) requested HLA-typing with concurrent exclusion of a single monogenic disease (58.6% for beta-thalassaemia). In 92.5% couples, both partners were fertile, with an average 1.93 HLA-PGD cycles/couple. Overall, 9751 oocytes were retrieved (13.9/cycle) and 5532 embryos were analysed (7.9/cycle). Most cycles involved fresh oocytes (94.9%) and Day 3 embryo biopsy (85.3%). In 97.5% of cycles, the genotyping method involved PCR only. Of 4343 embryos diagnosed (78.5% of analysed embryos), 677 were genetically suitable (15.4% of those analysed for HLA alone, 11.6% of those analysed for HLA with exclusion of monogenic disease). Of the 364 couples, 56.6% achieved an embryo transfer (ET) and 598 embryos were transferred in 382 cycles, leading to 164 HCG-positive pregnancies (pregnancy rate/ET 41.3%, pregnancy rate/initiated cycle 23.3%) and 136 babies born (live birth rate/ET 34.3%, live birth rate/initiated cycle 19.3%) to 113 couples. Data analysis identified the following limitations to the overall success of the HLA-PGD procedure: the age of the mother undergoing the treatment cycle, the number of oocytes collected per cycle and genetic chance. HSCT was reported for 57 cases, of which 64.9% involved combined umbilical cord-blood and bone marrow transplantation from the HLA-identical sibling donor; 77.3% of transplants reported no complications., Limitations Reasons for Caution: The findings of the study may be limited as not all PGD centres with PGD-HLA experience participated. Reporting bias on completion of the online database may be another potential limitation. Furthermore, the study is based on retrospective data collection from centres with variable practices and strategies for ART, embryology and genetic diagnosis., Wider Implications of the Findings: This is the first multi-centre study evaluating the clinical utility of PGD-HLA, indicating variations in practice and outcomes throughout 15 years and between centres. The study highlights parameters important for positive outcomes and provides important information for both scientists and couples interested in initiating a cycle. Above all, the study underlines the need for better collaboration between all specialists involved in the ART-PGD/HLA procedure, as well as the need for comprehensive and prospective long-term data collection, and encourages all specialists to aim to properly evaluate and follow-up all procedures, with the ultimate aim to promote best practice and encourage patient informed decision making., Study Funding/competing Interest(s): The study wishes to acknowledge ESHRE for funding the customization of the REDCap database. There are no competing interests., Trial Registration Number: N/A.

Fertility issues have become critical in the management and counseling of BRCA mutation carriers. In this setting four points deserve consideration. (1) Women in general lose their ability to conceive at a mean age of 41 years, thus the suggested policy of prophylactic bilateral salpingo-oophorectomy at age 40 for BRCA mutation carriers does not affect the chances of natural pregnancy. Conversely, if the procedure is chosen at 35 years old, oocyte cryopreservation prior to surgery should be considered. (2) Some evidence suggests that ovarian reserve may actually be partly reduced in BRCA mutations carriers and that the mutation may affect ovarian responsiveness to stimulation. However, these findings are still controversial. (3) Breast cancer is not rare before the age of 40 and fertility preservation after diagnosis can be requested in a significant proportion of BRCA mutation carriers. Thus, a policy of oocyte cryopreservation in young healthy carriers deserves consideration. The procedure could be considered at a young age and in an elective setting, when ovarian stimulation may yield more oocytes of better quality. (4) Preimplantation genetic diagnosis (PGD) could be considered in BRCA mutations carriers, particularly when good quality oocytes have been stored at a young age. Based on the current knowledge, a univocal approach cannot be recommended; in depth patient counseling is warranted., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Study Question: Does high gonadotropin dosage affect euploidy and pregnancy rates in PGS cycles with single embryo transfer?, Summary Answer: High gonadotropin dosage does NOT affect euploidy and pregnancy rates in PGS cycles with single embryo transfer., What Is Known Already: PGS has been proven to be the most effective and reliable method for embryo selection in IVF cycles. Euploidy and blastulation rates decrease significantly with advancing maternal age. In order to recruit an adequate number of follicles, the average dosage of gonadotropins administered during controlled ovarian stimulation in IVF cycles often increases significantly with advancing maternal age., Study Design, Size, and Duration: A retrospective study of SNP (Single Nucleotide Polymorphism) PGS outcome data from blastocysts biopsied on day 5 or day 6 was conducted to identify differences in euploidy and clinical pregnancy rates. Seven hundred and ninety four cycles of IVF treatment with PGS between January 2013 and January 2017 followed by 651 frozen embryo transfers were included in the study (506 patients, maternal age (y.o.) - 37.2 ± 4.31)., Participants/materials, Setting, Methods: A total of 4034 embryos were analyzed (5.1 ± 3.76 per case) for euploidy status. All embryos were vitrified after biopsy, and selected embryos were subsequently thawed for a hormone replacement frozen embryo transfer cycle. All cycles were analyzed by total gonadotropin dosage (<3000 IU, 3000-5000 IU and >5000 IU), by number of eggs retrieved (1-5, 5-10, 10-15 and >15 eggs) and patient's age (<35, 35-37, 38-40 and ≥41 y.o.). Clinical pregnancy rate was defined by the presence of a fetal heartbeat at 6-7 weeks of gestation., Main Results and the Role of Chance: Euploidy rates within the same age group were not statistically different regardless of the total dosage of gonadotropins used or the number of eggs retrieved. In the youngest group of patients (<35 y.o. - 187 IVF cycles) euploidy rates ranged from 62.3% (<3000 IU were used in the IVF cycle) to 67.5% (>5000 IU were used in the IVF cycle) (OR = 0.862, 95% CI 0.687-1.082, P = 0.2) and from 69.5% (1-5 eggs retrieved) to 60.0% (>15 eggs retrieved) (OR = 0.658, 95% CI 0.405-1.071, P = 0.09). Similar data were obtained in the oldest group of patients (≥41 y.o. - 189 IVF cycles): euploidy rates ranged from 30.7 to 26.4% (OR = 0.811, 95% CI 0.452-1.454, P = 0.481) when analyzed by total dosage of gonadotropins used in the IVF cycle and from 40.0 to 30.7% (OR = 0.531, 95% CI 0.204-1.384, P = 0.19), when assessed by the total number of eggs retrieved. Ongoing pregnancy rates were similar, not only within particular age groups, but also between different age groups regardless of the total dosage of gonadotropins used: ranging from to 63.6% (<3000 IU, < 35 y.o.) to 54.8% (>5000 IU, ≥41 y.o) (OR = 0.696, 95% CI 0.310-1.565, P = 0.38)., Limitations, Reasons for Caution: Retrospective study and heterogeneity of patients included., Wider Implications of the Findings: These data are reassuring for the common practice of increasing gonadotropin dosages in PGS cycles, particularly in older woman., Study Funding/competing Interest(s): No formal funding has been received for this study., Trial Registration Number: N/A., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com)

Study Question: What is the association between the ovarian response and the number of CGG repeats among full mutation and premutation carriers of fragile X (FMR1), undergoing controlled ovarian hyperstimulation (COH) for PGD?, Summary Answer: Ovarian response was normal in full mutation patients but decreased in premutation carriers, although the number of repeats was not statistically significantly associated with the number of oocytes retrieved., What Is Known Already: There is inconsistent data in the literature regarding ovarian response in FMR1 carriers. Studies exploring the ovarian response of full mutation patients are lacking., Study Design, Size, Duration: Retrospective study, a university affiliated tertiary hospital, IVF unit, PGD referral center., Participants/materials, Setting, Methods: We examined the medical records of all women undergoing fresh IVF-PGD cycles due to fragile X. Data recorded included demography, duration of stimulation, amount of gonadotropins administered, number of dominant follicles, maximal E2 levels and number of oocytes retrieved. Data were analyzed using univariate and multivariate mixed models. P-values <0.05 were considered significant. Data were collected from the medical records of 21 patients with a full mutation on the FMR1 gene and 51 premutation carriers. Overall 309 fresh cycles were analyzed., Main Results and the Role of Chance: Premutation carriers displayed reduced ovarian response, as demonstrated by fewer oocytes retrieved. In contrast, full mutation patients had a normal response. Comparison of premutation carriers and full mutation patients showed: mean oocytes retrieved per cycle (8.4 ± 1.1 versus 14.1 ± 1.7, P = 0.005), lower levels of estradiol (E2; 1756 ± 177, versus 2928 ± 263, P = 0.0004), respectively. There was no significant difference between premutation carriers and full mutation patients in regard to fertilization rate, cleavage rate or biopsy rate. No correlation was found between the number of repeats in the premutation carriers and the number of oocytes retrieved or E2 levels. Age and the type of protocol were the only factors found to be in correlation with the number of the oocyte retrieved (P = 0.037, and P = 0.003, respectively) among the premutation carriers. Similarly, no association was found between the number of repeats and the fertilization rate, cleavage rate or biopsy rate among premutation carriers., Limitations, Reasons for Caution: We had a relatively low number of premutation carriers with >100 repeats, which made it challenging to draw a firm conclusions from this group., Wider Implications of the Findings: Physicians must address the increased risk for reduced ovarian response and  primary ovarian insufficiency (POI) among carriers and consider surveillance of ovarian reserve markers. The last, might expedite family plans completion or fertility preservation., Study Funding/competing Interest(s): None., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Study Question: Do external factors affect euploidy in egg donor cycles?, Summary Answer: The study demonstrates that during human assisted reproduction, embryonic chromosome abnormalities may be partly iatrogenic., What Is Known Already: Chromosome abnormalities have been linked in the past to culture conditions such as temperature and Ph variations, as well as hormonal stimulation. Those reports were performed with older screening techniques (FISH), or ART methods no longer in use, and the subjects studied were not a homogeneous group., Study Design, Size, Duration: A total of 1645 donor oocyte cycles and 13 282 blastocyst biopsies from 42 fertility clinics were included in this retrospective cohort study. Samples from donor cycles with PGS attempted between September 2011 and July 2015 were included., Participants/materials, Setting, Methods: PGS cycles from multiple fertility clinics referred to Reprogenetics (Livingston, NJ) that involved only oocyte donation were included in this study. Testing was performed by array comparative genomic hybridization (aCGH). Ploidy data were analyzed using Generalized Linear Mixed Models with logistic regression using a logit link function considering a number of variables that represent fixed and random effects., Main Results and the Role of Chance: Euploidy rate was associated with the referring center and independent of almost all the parameters examined except donor age and testing technology. Average euploidy rate per center ranged from 39.5 to 82.5%. The mean expected rate of euploidy was 68.4%, but there are variations in this rate associated with the center effect., Limitations, Reasons for Caution: Data set does not include details of the donor selection process, donor race or ethnic origin, ovarian reserve or ovarian responsiveness. Due to the retrospective nature of the study, associations are apparent, however, causality cannot be established. Discrepancies in regard to completeness and homogeneity of data exist due to data collection from over 40 different clinics., Wider Implications of the Findings: This is the first study to show a strong association between center-specific ART treatment practices and the incidence of chromosome abnormality in human embryos, although the meiotic or mitotic origin of these abnormalities could not be determined using these technologies. Given the widespread applications of ART in both subfertile and fertile populations, our findings should be of interest to the medical community in general as well as the ART community in particular., Study Funding/competing Interest(s): No external funds were used for this study. S. Munne is a founding principle of Reprogenetics/current employee of Cooper Genomics. M Alikani's spouse is a founding principle of Reprogenetics/current consultant for Cooper Genomics. The remaining authors have no conflicts to declare., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Study Question: To what extent are BRCA mutation carriers and their partners in the Netherlands aware about preimplantation genetic diagnosis (PGD) and prenatal diagnosis (PND) as reproductive options and what is their attitude towards these options?, Summary Answer: Awareness of PGD (66%) and PND (61%) among BRCA mutation carriers and their partners is relatively high and 80% and 26%, respectively, of BRCA carriers and their partners find offering PGD and PND for hereditary breast and ovarian cancer (HBOC) acceptable., What Is Known Already: Internationally, awareness of PGD among persons with a genetic cancer predisposition appears to be relatively low (35%) and although acceptability is generally high (71%), only a small proportion of mutation carriers would consider using PGD (36%). However, for HBOC, there are no studies available that investigated the perspective of individuals with a confirmed BRCA1/2 mutation and their partners about PGD and PND including demographic and medical correlates of awareness and acceptability., Study Design, Size, Duration: A cross-sectional survey was completed by 191 participants between July 2012 and June 2013. Participants were recruited through patient organizations (88%) and the databases of two Clinical Genetics departments in the Netherlands (12%)., Participants/materials, Setting, Methods: Male and female BRCA carriers and their partners completed an online survey, which assessed demographic and medical characteristics, and awareness, knowledge, acceptability and consideration of PGD and PND as main outcomes. Correlations between demographic and medical characteristics and the main outcomes were investigated., Main Results and Role of Chance: The majority of respondents were female (87%), of reproductive age (86%) and about half reported a desire for a child in the future. About two-thirds (66%) were aware of PGD and 61% of PND for HBOC. PGD knowledge was moderate (5.5 on a 9-point scale) and acceptability of PGD and PND for HBOC was 80% and 26%, respectively. A minority would personally consider using PGD (39%) or PND (20%). Individuals with a higher educational level were more likely to be aware of PGD (P < 0.001) and PND (P < 0.001) and persons with a more immediate child wish were more often aware of PGD (P = 0.044) and had more knowledge about PGD (P = 0.001). PGD acceptability was positively associated with knowledge about PGD (P = 0.047), and PND acceptability was higher among partners in comparison to carriers (P = 0.001). Participants with a history of cancer and with a higher perceived seriousness of breast and ovarian cancer were more likely to consider using PGD (P = 0.003 and P < 0.001 respectively) or PND (P = 0.021 and P = 0.017 respectively)., Limitations, Reasons for Caution: The response rate (23%) of participants invited by the clinical genetics departments was low, probably related to a simultaneous study that used a similar recruitment strategy within the same target group, which may have resulted in selection bias. Moreover, PGD knowledge was measured with an instrument that is not yet validated since to date such an instrument is not available in the literature. Finally, the cross-sectional design of this study limits us from drawing any causal conclusions., Wider Implications of the Findings: Improvement of information provision remains needed, in order to timely inform all couples with HBOC about the available reproductive options and enable them to make a balanced reproductive decision. This may limit the risk of negative psychological impact due to decisional conflict and possible regret., Study Funding/competing Interest(s): The Dutch breast cancer foundation Stichting Pink Ribbon (grant number 2010.PS11.C74). None of the authors have competing interests to declare., Trial Registration Number: Not applicable., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

We report on the first PGD performed for the m.14487 T>C mitochondrial DNA (mtDNA) mutation in the MT-ND6 gene, associated with Leigh syndrome. The female carrier gave birth to a healthy baby boy at age 42. This case adds to the successes of PGD for mtDNA mutations., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Embryonic mosaicism, defined as the presence of karyotypically distinct cell lines within an embryo, has been frequently reported with a high incidence in preimplantation embryos derived from IVF and is thought to be one of the major biological limitations for the routine application of PGD for aneuploidies (PGD-A). The incidence of mosaicism in preimplantation embryos is in fact reported to be between 4 and 90%. However, these data are in sharp contrast with what is known from clinical pregnancies, where true foetal mosaicism is observed in less than 0.5% of cases. Here, we challenge these previous observations in preimplantation embryos, presenting an alternative perspective, which also considers the impact of technical variation to diagnose mosaicism as one possible cause contributing to overestimation of the incidence of mosaicism in embryos. Although euploid/aneuploid mosaicism may be present in blastocysts, the possibility of detecting this phenomenon within a single trophectoderm biopsy represents a contemporary challenge to bring about improvement to the practice of PGD-A. The purpose of this opinion paper is to provide a critical review of the literature, provide a possible alternative interpretation of the data, and discuss future challenges with diagnosing mosaicism in PGD-A cycles., (© The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.)

Study Question: In an intent to treat analysis, are clinical outcomes improved in recurrent pregnancy loss (RPL) patients undergoing IVF and preimplantation genetic screening (PGS) compared with patients who are expectantly managed (EM)?, Summary Answer: Among all attempts at PGS or EM among RPL patients, clinical outcomes including pregnancy rate, live birth (LB) rate and clinical miscarriage (CM) rate were similar., What Is Known Already: The standard of care for management of patients with RPL is EM. Due to the prevalence of aneuploidy in CM, PGS has been proposed as an alternate strategy for reducing CM rates and improving LB rates., Study Design, Size, Duration: Retrospective cohort study of 300 RPL patients treated between 2009 and 2014., Participants/materials, Setting, Methods: Among two academic fertility centers, 112 RPL patients desired PGS and 188 patients chose EM. Main outcomes measured were pregnancy rate and LB per attempt and CM rate per pregnancy. One attempt was defined as an IVF cycle followed by a fresh embryo transfer or a frozen embryo transfer (PGS group) and 6 months trying to conceive (EM group)., Main Results and the Role of Chance: In the IVF group, 168 retrievals were performed and 38 cycles canceled their planned PGS. Cycles in which PGS was intended but cancelled had a significantly lower LB rate (15 versus 36%, P = 0.01) and higher CM rate (50 versus 14%, P < 0.01) compared with cycles that completed PGS despite similar maternal ages. Of the 130 completed PGS cycles, 74% (n = 96) yielded at least one euploid embryo. Clinical pregnancy rate per euploid embryo transfer was 72% and LB rate per euploid embryo transfer was 57%. Among all attempts at PGS or EM, clinical outcomes were similar. Median time to pregnancy was 6.5 months in the PGS group and 3.0 months in the EM group., Limitations, Reasons for Caution: The largest limitation is the retrospective study design, in which patients who elected for IVF/PGS may have had different clinical prognoses than patients who elected for expectant management. In addition, the definition of one attempt at conception for PGS and EM groups was different between the groups and can introduce potential confounders. For example, it was not confirmed that patients in the EM group were trying to conceive for each month of the 6-month period., Wider Implications of the Finding: Success rates with PGS are limited by the high incidence of cycles that intend but cancel PGS or cycles that do not reach transfer. Counseling RPL patients on their treatment options should include not only success rates with PGS per euploid embryo transferred, but also LB rate per initiated PGS cycle. Furthermore, patients who express an urgency to conceive should be counseled that PGS may not accelerate time to conception., Study Funding/competing Interests: None., Trial Registration Number: N/A., Trial Registration Date: N/A., Date of First Patient's Enrollment: N/A., (© The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)