Which factors affect the live birth outcome of the first single euploid frozen-thawed blastocyst transfer in couples with balanced chromosomal translocations?

Objective: The objective of this study is to investigate the factors that influence the live birth rate (LBR) of the first single euploid frozen-thawed blastocyst transfer (FBT) cycles after preimplantation genetic testing for structural rearrangements (PGT-SR) in couples with balanced chromosomal translocations (BCT). Design: Single center, retrospective and observational study. Methods: A total of 336 PGT-SR and the first single euploid FBT cycles between July 2016 and December 2022 were included in this study. The patients were divided into two groups according to the live birth outcomes. The parameters of the study population, controlled ovarian stimulation cycles, and FBT cycles were analyzed. Multivariable binary logistic regression was performed to find the factors that affected the LBR. Results: The percentage of blastocysts at developmental stage Day 5 compared to Day 6 (51.8% vs. 30.8%; P<0.001) and with morphology ≥BB compared to

Embryology with precision: effective quality control in the in vitro fertilization laboratory.

The purpose of this review is to address the critical need for standardization and clarity in the use of key performance indicators (KPIs) within the realm of in vitro fertilization (IVF), particularly emphasizing the integration of preimplantation genetic testing (PGT) processes. This review is timely and relevant given the persistently modest success rates of IVF treatments, which stand at approximately 30%, and the growing complexity of IVF procedures, including PGT practices. The review synthesizes recent findings across studies focusing on technical and clinical KPIs in embryology and genetic laboratories, identifying gaps in current research and practice, particularly the lack of standardized KPIs and terminology. Recent findings highlighted include the critical evaluation of technical KPIs such as Intracytoplasmic Sperm Injection (ICSI) fertilization rates, embryo development rates, and laboratory performance metrics, alongside clinical KPIs like the proportion of mature oocytes and clinical pregnancy rates. Notably, the review uncovers a significant gap in integrating and standardizing KPIs for PGT applications, which is essential for improving IVF outcomes and genetic diagnostic accuracy. The implications of these findings are profound for both clinical practice and research. For clinical practice, establishing a standardized set of KPIs, especially for PGT, could significantly enhance the success rates of IVF treatments by providing clearer benchmarks for quality and performance. For research, this review underscores the necessity for further studies to close the identified gaps, promoting a more integrated and standardized approach to KPIs in IVF and PGT processes. This comprehensive approach will not only aid in improving clinical outcomes but also in advancing the field of reproductive medicine.

Successful preimplantation genetic testing for fibrodysplasia ossificans progressiva: a case report.

PURPOSE OF THE STUDY: Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant condition that leads to significant disability and morbidity, characterised by the formation of heterotopic hard tissues within connective tissues. The condition has an incidence of approximately one per two million people worldwide. There is no known single effective treatment available for FOP. We report the world's first case of a healthy infant born following in vitro fertilisation (IVF) and preimplantation genetic testing for monogenic disorder (PGT-M) using Karyomapping for FOP. CASE PRESENTATION: A 30-year-old Caucasian female with FOP presented with her partner seeking IVF with PGT-M to achieve a healthy pregnancy with an embryo unaffected by FOP. METHODS: The couple underwent IVF and PGT-M using Karyomapping as the testing method. A multi-disciplinary team approach was utilised in planning this case, considering the additional risks of oocyte retrieval, pregnancy and childbirth in women with FOP. MAIN FINDINGS: The oocyte retrieval was covered with a 5-day course of prednisolone to reduce the risk of a localised inflammatory reaction, which could result in subsequent heterotopic ossification. This was subsequently weaned down with reducing doses every two days. The patient underwent uncomplicated oocyte retrieval, yielding 12 mature oocytes. Following intracytoplasmic sperm injection (ICSI), ten zygotes having two pro-nuclei were cultured, and six underwent trophoectoderm biopsy and vitrification 5-6 days after retrieval. PGT-M via Karyomapping revealed four out of six (66.7%) of blastocysts were not carriers of the maternal high-risk FOP allele. In total, the patient had three separate embryo transfers. Pregnancy was achieved following the third frozen embryo transfer, which went to 37 weeks' gestation, and delivered by Caesarean section. The baby was born in excellent condition and is unaffected by FOP. CONCLUSION: IVF/ICSI and PGT-M using Karyomapping was successfully implemented to identify embryos carrying the high-risk FOP allele resulting in a healthy livebirth.

What Do Prospective Parents Owe to Their Children?

I consider the question of what moral obligations prospective parents owe to their future children. It is taken as an almost axiomatic premise of a wide range of philosophical arguments that prospective parents have a moral obligation to take such steps as ensuring their own financial stability or waiting until they are emotionally mature before conceiving. This is because it is assumed that parents have a moral obligation to lay the groundwork for their children's lives to go well. While at first glance such a premise seems benign, I will argue that when it is applied to arguments in assisted reproductive technology, as it is in Julian Savulescu's procreative beneficence argument or as it is in Daniel Groll's recent argument for open gamete donation, we see problems with this premise. Problems in Groll's argument also become apparent when it is scrutinized in connection with this premise.

[Preimplantation genetic testing for a Chinese pedigree affected with Rett syndrome].

OBJECTIVE: To carry out preimplantation genetic testing (PGT) for a Chinese pedigree affected with Rett syndrome (RTT). METHODS: A pedigree affected with RTT who had presented at the First Hospital of Jilin University on June 4, 2021 was selected as the study subject. Variant of the MECP2 gene was analyzed by next generation sequencing (NGS) and Sanger sequencing. Direct sequencing was also used to determine the carrier status for the c.925C>T variant of the MECP2 gene in the blastocysts, and Sanger sequencing was used to validate the results. The MECP2 gene and 168 effective single nucleotide polymorphism (SNP) loci within 2 Mb ranges up- and downstream of the gene were used to construct a haplotype for analyzing the variant site in the embryos, and embryos without the variant were subjected to the analysis for chromosomal aneuploidies. RESULTS: PGT analysis revealed that five out of seven blastocysts did not harbor the pathogenic variant. The results of aneuploidy analysis indicated that two out of five blastocysts without the variant were euploid. Following genetic counselling, the couple had opted to transplant the optimal blastocyst. Following clinical pregnancy, prenatal diagnosis showed that the fetus has a normal chromosomal karyotype, and the c.925C>T variant was not detected in the amniotic fluid sample. A healthy girl was born by Cesarean section at full term. CONCLUSION: NGS can attain efficient PGT detection and reduce the risk of disease recurrence in families affected with RTT.

Influence of the number of washings for embryos on non-invasive preimplantation chromosome screening results.

Objective: To explore the effect of varying numbers of embryo washings prior to blastocyst formation in non-invasive preimplantation chromosome screening (NICS) on the accuracy of NICS results. Methods: In this study, 68 blastocysts from preimplantation genetic testing (PGT)-assisted pregnancy were collected at our institution. On the fourth day of embryo culture, the embryos were transferred to a new medium for blastocyst culture and were washed either three times (NICS1 group) or ten times (NICS2 group). A trophectoderm (TE) biopsy was performed on the blastocysts, and the corresponding embryo culture media were collected for whole genome amplification (WGA) and high-throughput sequencing. Results: The success rate of WGA was 100% (TE biopsy), 76.7% (NICS1 group), and 89.5% (NICS2 group). The success rate of WGA in embryo medium on days 5 and 6 of culture was 75.0% (33/44) and 100% (24/24), respectively. Using TE as the gold standard, the karyotype concordance rate between the results of the NICS1 and NICS2 groups' embryo culture medium samples and TE results was 43.5% (10/23) and 73.5% (25/34), respectively. The sensitivity and specificity of detecting chromosomal abnormalities were higher in the NICS2 group than in the NICS1 group when TE was used (83.3% vs 60.0%; 62.5% vs 30.8%, respectively). The false-positive rate and false-negative rate (i.e., misdiagnosis rate and missed diagnosis rate, respectively) were lower in the NICS2 group than in the NICS1 group (37.5% vs 69.2%; 16.7% vs 40.0%, respectively). Conclusion: The NICS yielded favorable results after ten washings of the embryos. These findings provide a novel method for lowering the amount of cell-free DNA contamination from non-embryonic sources in the medium used for embryo development, optimizing the sampling procedure and improving the accuracy of the NICS test.

[Analysis of related factors influencing the detection rate of mosaic embryo and the pregnancy outcomes with mosaic embryo transfers].

Objective: To explore the related factors influencing the detection rate of mosaic embryo and the pregnancy outcomes of mosaic embryo transfer in preimplantation genetic testing for aneuploidy (PGT-A) based on next generation sequencing (NGS) technology. Methods: A retrospective study was performed to analyze the clinical data of patients in 745 PGT-A cycles from January 2019 to May 2023 at Chongqing Health Center for Women and Children, including 2 850 blastocysts. The biopsy cells were tested using NGS technology, and the embryos were divided into three groups based on the test results, namely euploid embryos, aneuploid embryos and mosaic embryos. The influence of population characteristics and laboratory-related parameters on the detection rate of mosaic embryo were analyzed, and the pregnancy outcomes of 98 mosaic embryo transfer cycles and 486 euploid embryo transfer cycles were compared during the same period, including clinical pregnancy rate and live birth rate. Results: Among the embryos tested (n=2 850), the number and proportion of euploid embryos, aneuploid embryos and mosaic embryos were 1 489 (52.2%, 1 489/2 850), 917 (32.2%, 917/2 850) and 444 (15.6%, 444/2 850), respectively. Among mosaic embryos, 245 (55.2%, 245/444) were segmental mosaic embryos, 118 (26.6%, 118/444) were whole-chromosome mosaic embryos, and 81 (18.2%, 81/444) were complex mosaic embryos. NGS technology was performed in 4 genetic testing institutions and the detection rate of mosaic embryo fluctuated from 13.5% to 27.0%. The distributions of female age, level of anti-Müllerian hormone, PGT-A indications, ovulation-inducing treatments, gonadotropin (Gn) dosage, Gn days, inner cell mass grade, trophectoderm cell grade, genetic testing institutions and developmental stage of blastocyst were significantly different among the three groups (all P<0.05). Multi-factor analysis showed that the trophectoderm cell grade and genetic testing institutions were significantly related to the detection rate of mosaic embryo; compared with the trophectoderm cell graded as A, the detection rate of mosaic embryo was significantly increased in the trophectoderm cell graded as B-(OR=1.59, 95%CI: 1.04-2.44, P=0.033); compared with genetic testing institution a, the detection rate of mosaic embryo was significantly higher (OR=2.89, 95%CI: 2.10-3.98, P<0.001) in the testing institution c. The clinical pregnancy rate and live birth rate with mosaic embryos transfer were significantly lower than those of euploid embryos transfer (clinical pregnancy rate: 51.0% vs 65.2%, P=0.008; live birth rate: 39.4% vs 53.2%, P=0.017). After adjustment for age, PGT-A indications, trophectoderm cell grade and days of embryo culture in vitro, the clinical pregnancy rate and live birth rate with mosaic embryos transfer were significantly lower than those of euploid embryos transfer (clinical pregnancy rate: OR=0.52, 95%CI: 0.32-0.83, P=0.007; live birth rate: OR=0.50, 95%CI: 0.31-0.83, P=0.007). Conclusions: The trophectoderm cell grade and genetic testing institutions are related to the detection rate of mosaic embryo. Compared with euploid embryos transfer, the clinical pregnancy rate and live birth rate with mosaic embryos transfer are significantly reduced. For infertile couple without euploid embryos, transplantable mosaic embryos could be recommended according to the mosaic ratio and mosaic type in genetic counseling to obtain the optimal pregnancy outcome.

Diagnóstico genético de la hipoacusia neurosensorial infantil / Genetic diagnosis of childhood sensorineural hearing loss

Introducción: La hipoacusia neurosensorial (HNS) congénita o de inicio precoz es una de las enfermedades hereditarias más frecuentes en nuestro medio y es la deficiencia sensorial más frecuente. Es importante realizar un estudio etiológico de la hipoacusia y el estudio genético mediante la secuenciación de nueva generación (NGS) es la prueba con mayor rendimiento diagnóstico. Nuestro estudio muestra los resultados genéticos obtenidos en una serie de pacientes con HNS congénita/de inicio precoz bilateral. Material y método: Se incluyeron 105 niños diagnosticados de HNS bilateral a los que se les realizó un estudio genético entre los años 2019 y 2022. El estudio genético consistió en una secuenciación masiva del exoma completo, filtrando el análisis para los genes incluidos en un panel virtual de hipoacusia con 244 genes. Resultados: Se obtuvo un diagnóstico genético en 48% (50/105) de los pacientes. Se detectaron variantes patogénicas y probablemente patogénicas en 26 genes diferentes, siendo los genes más frecuentemente afectados el gen GJB2, USH2A y STRC. De las variantes detectadas 52% (26/50) se asociaron a una hipoacusia no sindrómica, 40% (20/50) una hipoacusia sindrómica y 8% restante (4/50) se podían asociar tanto a una hipoacusia sindrómica como no sindrómica. Conclusiones: El estudio genético constituye una parte fundamental del diagnóstico etiológico de la HNS bilateral. Nuestra serie muestra que el estudio genético de la hipoacusia mediante NGS tiene un alto rendimiento diagnóstico y nos proporciona información de gran utilidad en la práctica clínica.(AU)

Introduction: Congenital/early-onset sensorineural hearing loss (SNHL) is one of the most common hereditary disorders in our environment. There is increasing awareness of the importance of an etiologic diagnosis, and genetic testing with next-generation sequencing (NGS) has the highest diagnostic yield. Our study shows the genetic results obtained in a cohort of patients with bilateral congenital/early-onset SNHL. Materials and methods: We included 105 children with bilateral SNHL that received genetic testing between 2019 and 2022. Genetic tests were performed with whole exome sequencing, analyzing genes related to hearing loss (virtual panel with 244 genes). Results: 48% (50/105) of patients were genetically diagnosed. We identified pathogenic and likely pathogenic variants in 26 different genes, and the most frequently mutated genes were GJB2, USH2A and STRC. 52% (26/50) of variants identified produced non-syndromic hearing loss, 40% (20/50) produced syndromic hearing loss, and the resting 8% (4/50) could produce both non-syndromic and syndromic hearing loss. Conclusions: Genetic testing plays a vital role in the etiologic diagnosis of bilateral SNHL. Our cohort shows that genetic testing with NGS has a high diagnostic yield and can provide useful information for the clinical workup of patients.(AU)

Clinical Guideline for Preimplantation Genetic Testing in Inherited Cardiac Diseases.

BACKGROUND: Preimplantation genetic testing (PGT) is a reproductive technology that selects embryos without (familial) genetic variants. PGT has been applied in inherited cardiac disease and is included in the latest American Heart Association/American College of Cardiology guidelines. However, guidelines selecting eligible couples who will have the strongest risk reduction most from PGT are lacking. We developed an objective decision model to select eligibility for PGT and compared its results with those from a multidisciplinary team. METHODS: All couples with an inherited cardiac disease referred to the national PGT center were included. A multidisciplinary team approved or rejected the indication based on clinical and genetic information. We developed a decision model based on published risk prediction models and literature, to evaluate the severity of the cardiac phenotype and the penetrance of the familial variant in referred patients. The outcomes of the model and the multidisciplinary team were compared in a blinded fashion. RESULTS: Eighty-three couples were referred for PGT (1997-2022), comprising 19 different genes for 8 different inherited cardiac diseases (cardiomyopathies and arrhythmias). Using our model and proposed cutoff values, a definitive decision was reached for 76 (92%) couples, aligning with 95% of the multidisciplinary team decisions. In a prospective cohort of 11 couples, we showed the clinical applicability of the model to select couples most eligible for PGT. CONCLUSIONS: The number of PGT requests for inherited cardiac diseases increases rapidly, without the availability of specific guidelines. We propose a 2-step decision model that helps select couples with the highest risk reduction for cardiac disease in their offspring after PGT.

Single-cell sequencing shows mosaic aneuploidy in most human embryos.

Mammalian preimplantation embryos often contain chromosomal defects that arose in the first divisions after fertilization and affect a subpopulation of cells - an event known as mosaic aneuploidy. In this issue of the JCI, Chavli et al. report single-cell genomic sequencing data for rigorous evaluation of the incidence and degree of mosaic aneuploidy in healthy human in vitro fertilization (IVF) embryos. Remarkably, mosaic aneuploidy occurred in at least 80% of human blastocyst-stage embryos, with often less than 20% of cells showing defects. These findings confirm that mosaic aneuploidy is prevalent in human embryos, indicating that the process is a widespread event that rarely has clinical consequences. There are major implications for preimplantation genetic testing of aneuploidy (PGT-A), a test commonly used to screen and select IVF embryos for transfer. The application and benefit of this technology is controversial, and the findings provide more cause for caution on its use.

Effects of first and second division modes on euploidy acquisition in human embryo.

The aim of this study was to non-invasively investigate euploid embryos using methods other than pre-implantation genetic testing for aneuploidy. The study focused on direct cleavage (DC) observed during early embryo development. We also investigated the relationship between the mode of early embryo division and embryo ploidy. Embryos were divided into the normal cleavage (NC) and DC groups, and the DC group was further subdivided into the DC-First (DC-F) and DC-Second (DC-S) groups, depending on whether DC was observed at the first or second cleavage, respectively. The acquisition rates of euploid embryos and embryos appropriate for transfer were compared between the groups. Our results revealed that the timing of the first division did not differ between blastocyst grades or in embryos with varying degrees of ploidy. Further, the timing of the first cleavage did not affect the acquisition rate of embryos appropriate for transfer and euploid embryo formation rate did not significantly differ between the DC and NC groups. We also noted that for embryos appropriate for transfer, euploidy acquisition rate did not differ significantly between the DC and NC groups. Further, the euploidy acquisition rate of embryos did not differ between the DC-F and DC-S groups. However, the acquisition rate of embryos appropriate for transfer, including those with low mosaicism, was significantly higher in the DC-S group than in the DC-F group. These findings indicated that the number of good-quality blastocysts formed was significantly higher in the NC group than in the DC group and the acquisition rate of embryos appropriate for transfer, including those with low mosaicism, was significantly higher in the DC-S group than in the DC-F group.

Economic evaluations of assisted reproductive technologies in high-income countries: a systematic review.

STUDY QUESTION: Which assited reproductive technology (ART) interventions in high-income countries are cost-effective and which are not? SUMMARY ANSWER: Among all ART interventions assessed in economic evaluations, most high-cost interventions, including preimplantation genetic testing for aneuploidy (PGT-A) for a general population and ICSI for unexplained infertility, are unlikely to be cost-effective owing to minimal or no increase in effectiveness. WHAT IS KNOWN ALREADY: Approaches to reduce costs in order to increase access have been identified as a research priority for future infertility research. There has been an increasing number of ART interventions implemented in routine clinical practice globally, before robust assessments of evidence on economic evaluations. The extent of clinical effectiveness of some studied comparisons has been evaluated in high-quality research, allowing more informative decision making around cost-effectiveness. STUDY DESIGN, SIZE, DURATION: We performed a systematic review and searched seven databases (MEDLINE, PUBMED, EMBASE, COCHRANE, ECONLIT, SCOPUS, and CINAHL) for studies examining ART interventions for infertility together with an economic evaluation component (cost-effectiveness, cost-benefit, cost-utility, or cost-minimization assessment), in high-income countries, published since January 2011. The last search was 22 June 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Two independent reviewers assessed publications and included those fulfilling the eligibility criteria. Studies were examined to assess the cost-effectiveness of the studied intervention, as well as the reporting quality of the study. The chosen outcome measure and payer perspective were also noted. Completeness of reporting was assessed against the Consolidated Health Economic Evaluation Reporting Standard. Results are presented and summarized based on the intervention studied. MAIN RESULTS AND THE ROLE OF CHANCE: The review included 40 studies which were conducted in 11 high-income countries. Most studies (n = 34) included a cost-effectiveness analysis. ART interventions included medication or strategies for controlled ovarian stimulation (n = 15), IVF (n = 9), PGT-A (n = 7), single embryo transfer (n = 5), ICSI (n = 3), and freeze-all embryo transfer (n = 1). Live birth was the mostly commonly reported primary outcome (n = 27), and quality-adjusted life years was reported in three studies. The health funder perspective was used in 85% (n = 34) of studies. None of the included studies measured patient preference for treatment. It remains uncertain whether PGT-A improves pregnancy rates compared to IVF cycles managed without PGT-A, and therefore cost-effectiveness could not be demonstrated for this intervention. Similarly, ICSI in non-male factor infertility appears not to be clinically effective compared to standard fertilization in an IVF cycle and is therefore not cost-effective. Interventions such as use of biosimilars or HMG for ovarian stimulation are cheaper but compromise clinical effectiveness. LIMITATIONS, REASONS FOR CAUTION: Lack of both preference-based and standardized outcomes limits the comparability of results across studies. The selection of efficacy evidence offered for some interventions for economic evaluations is not always based on high-quality randomized trials and systematic reviews. In addition, there is insufficient knowledge of the willingness to pay thresholds of individuals and state funders for treatment of infertility. There is variable quality of reporting scores, which might increase uncertainty around the cost-effectiveness results. WIDER IMPLICATIONS OF THE FINDINGS: Investment in strategies to help infertile people who utilize ART is justifiable at both personal and population levels. This systematic review may assist ART funders decide how to best invest to maximize the likelihood of delivery of a healthy child. STUDY FUNDING/COMPETING INTEREST(S): There was no funding for this study. E.C. and R.W. receive salary support from the National Health and Medical Research Council (NHMRC) through their fellowship scheme (EC GNT1159536, RW 2021/GNT2009767). M.D.-T. reports consulting fees from King Fahad Medical School. All other authors have no competing interests to declare. REGISTRATION NUMBER: Prospero CRD42021261537.

Evaluation of Nanopore Sequencing on Polar Bodies for Routine Pre-Implantation Genetic Testing for Aneuploidy.

BACKGROUND: Preimplantation genetic testing for aneuploidy (PGT-A) using polar body (PB) biopsy offers a clinical benefit by reducing the number of embryo transfers and miscarriage rates but is currently not cost-efficient. Nanopore sequencing technology opens possibilities by providing cost-efficient and fast sequencing results with uncomplicated sample preparation work flows. METHODS: In this comparative experimental study, 102 pooled PB samples (99 passing QC) from 20 patients were analyzed for aneuploidy using nanopore sequencing technology and compared with array comparative genomic hybridization (aCGH) results generated as part of the clinical routine. Samples were sequenced on a Nanopore MinION machine. Whole-chromosome copy-numbers were called by custom bioinformatic analysis software. Automatically called results were compared to aCGH results. RESULTS: Overall, 96/99 samples were consistently detected as euploid or aneuploid in both methods (concordance = 97.0%, sensitivity = 0.957, specificity = 1.0, positive predictive value = 1.0, negative predictive value = 0.906). On the chromosomal level, concordance reached 98.7%. Chromosomal aneuploidies analyzed in this trial covered all 23 chromosomes with 98 trisomies, and 97 monosomies in 70 aCGH samples.The whole nanopore work flow is feasible in under 5 h (for one sample) with a maximum time of 16 h (for 12 samples), enabling fresh PB-euploid embryo transfer. A material cost of US$ 165 (EUR 150)/sample possibly enables cost-efficient aneuploidy screening. CONCLUSIONS: This is the first study systematically comparing nanopore sequencing with standard methods for the detection of PB aneuploidy. High concordance rates confirmed the feasibility of nanopore technology for this application. Additionally, the fast and cost-efficient work flow reveals the clinical utility of this technology, making it clinically attractive for PB PGT-A.

Ready for polygenic risk scores? An analysis of regulation of preimplantation genetic testing in European countries.

STUDY QUESTION: Would the different regulatory approaches for preimplantation genetic testing (PGT) in Europe permit the implementation of preimplantation genetic testing using polygenic risk scores (PGT-P)? SUMMARY ANSWER: While the regulatory approaches for PGT differ between countries, the space provided for potential implementation of PGT-P seems limited in all three regulatory models. WHAT IS KNOWN ALREADY: PGT is a reproductive genetic technology that allows the testing for hereditary genetic disorders and chromosome abnormalities in embryos before implantation. Throughout its history, PGT has largely been regarded as an ethically sensitive technology. For example, ethical questions have been raised regarding the use of PGT for adult-onset conditions, non-medical sex selection, and human leukocyte antigen typing for the benefit of existing siblings. Countries in which PGT is offered each have their own approach of regulating the clinical application of PGT, and a clear overview of legal and practical regulation of PGT in Europe is lacking. An emerging development within the field of PGT, namely PGT-P, is currently bringing new ethical tensions to the forefront. It is unclear whether PGT-P may be applied within the current regulatory frameworks in Europe. Therefore, it is important to investigate current regulatory frameworks in Europe and determine whether PGT-P fits within these frameworks. STUDY DESIGN, SIZE, DURATION: The aim of this study was to provide an overview of the legal and practical regulation of the use of PGT in seven selected European countries (Belgium, France, Germany, Italy, the Netherlands, Spain, and the UK) and critically analyse the different approaches with regards to regulatory possibilities for PGT-P. Between July and September 2023, we performed a thorough and extensive search of websites of governments and governmental agencies, websites of scientific and professional organizations, and academic articles in which laws and regulations are described. PARTICIPANTS/MATERIALS, SETTING, METHODS: We investigated the legal and regulatory aspects of PGT by analysing legal documents, regulatory frameworks, scientific articles, and guidelines from scientific organizations and regulatory bodies to gather relevant information about each included country. The main sources of information were national laws relating to PGT. MAIN RESULTS AND THE ROLE OF CHANCE: We divided the PGT regulation approaches into three models. The regulation of PGT differs per country, with some countries requiring central approval of PGT for each new indication (the medical indication model: the UK, the Netherlands), other countries evaluating each individual PGT request at the local level (the individual requests model: France, Germany), and countries largely leaving decision-making about clinical application of PGT to healthcare professionals (the clinical assessment model: Belgium, Italy, Spain). In the countries surveyed that use the medical indication model and the individual requests model, current legal frameworks and PGT criteria seem to exclude PGT-P. In countries using the clinical assessment model, the fact that healthcare professionals and scientific organizations in Europe are generally negative about implementation of PGT-P due to scientific and socio-ethical concerns, implies that, even if it were legally possible, the chance that PGT-P would be offered in the near future might be low. LIMITATIONS, REASONS FOR CAUTION: The results are based on our interpretation of publicly available written information and documents, therefore not all potential discrepancies between law and practice might have been identified. In addition, our analysis focuses on seven-and not all-European countries. However, since these countries are relevant players within PGT in Europe and since they have distinct PGT regulations, the insights gathered give relevant insights into diverse ways of PGT regulation. WIDER IMPLICATIONS OF THE FINDINGS: To the best of our knowledge, this is the first paper that provides a thorough overview of the legal and practical regulation of PGT in Europe. Our analysis of how PGT-P fits within current regulation models provides guidance for healthcare professionals and policymakers in navigating the possible future implementation of PGT-P within Europe. STUDY FUNDING/COMPETING INTEREST(S): This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 813707. The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Primary sex ratio in euploid embryos of consanguine couples after IVF/ICSI.

PURPOSE: To assess the primary sex ratio (males-to-females at time of conception) in blastocysts from consanguine couples undergoing IVF/ICSI treatments and its correlation with chromosomal constitution. METHOD: A total of 5135 blastocysts were analyzed by preimplantation-genetic testing for aneuploidy (PGT-A) with next-generation sequencing (NGS) from November 2016 to December 2020. From those, a total of 1138 blastocysts were from consanguine couples (CS) and 3997 from non-consanguine couples (NCS). Only blastocysts presenting normal sex chromosome constitution with or without autosomal aneuploidies were included. Primary sex ratio (PSR) of biopsied blastocysts was compared between CS and NCS couples. RESULTS: Expanded blastocysts derived from CS had 47.7% XY versus 52.3% XX constitutions, presenting a PSR of 0.91. In NCS, 48.9% of expanded blastocysts were XY and 51.2% XX, with a less pronounced PSR of 0.95. When stratifying embryos by ploidy, euploid embryos from CS had the lowest PSR (0.87) with 46.6% XY versus 53.4% XX blastocysts (OR 0.89, 95% CI 0.70-1.14; NS), but it did not achieve statistical significance. The lower PSR seemed rather related to euploid embryos from first-degree cousins (PSR = 0.80 versus 0.98 in second-degree cousins, NS). Euploid embryos from NCS presented a PSR of 0.96, with 49.1% XY versus 50.9% XX blastocysts (OR 0.98, 95% CI 0.79-1.22; NS). Significant differences in prevalence of euploidy of specific chromosomes were encountered between CS and NCS. CONCLUSIONS: The primary sex ratio was generally similar in expanded blastocysts from consanguine and non-consanguine couples, with a slight decrease in primary sex ratio of euploid blastocysts from consanguine couples.

Blastocysts from partial compaction morulae are not defined by their early mistakes.

RESEARCH QUESTION: Is partial compaction during morula formation associated with an embryo's developmental ability and implantation potential? DESIGN: Retrospective analysis of data from 196 preimplantation genetic testing for aneuploidy (PGT-A) cycles. Embryos starting compaction were grouped according to the inclusion or not of all the blastomeres in the forming morula (full compaction or partial compaction). The possible effect of maternal age and ovarian response on compaction was analysed. Morphokinetic characteristics, blastocyst formation rate, morphology and cytogenetic constitution of the obtained blastocysts were compared. Comparisons of reproductive outcomes after the transfer of euploid blastocysts from both groups were established. Finally, in a subset of embryos, the chromosomal constitution concordance of the abandoned cells and the corresponding blastocyst through trophectoderm biopsies was assessed. RESULTS: A total of 430 embryos failed to include at least one cell during compaction (partial compaction group [49.3%]), whereas the 442 remaining embryos formed a fully compacted morula (full compaction group [50.7%]). Neither female age nor the number of oocytes collected affected the prevalence of partial compaction morulae. Morphokinetic parameters were altered in embryos from partial compaction morulae compared with full compaction. Although an impairment in blastocyst formation rate was observed in partial compaction morulae (57.2% versus 70.8%, P < 0.001), both chromosomal constitution (euploidy rate: partial compaction [38.4%] versus full compaction [34.2%]) and reproductive outcomes (live birth rate: partial compaction [51.9%] versus full compaction [46.2%]) of the obtained blastocysts were equivalent between groups. A high ploidy correlation of excluded cells-trophectoderm duos was observed. CONCLUSIONS: Partial compaction morulae show a reduced developmental ability compared with full compaction morulae. Resulting blastocysts from both groups, however, have similar euploidy rates and reproductive outcomes. Cell exclusion might be a consequence of a compromised embryo development regardless of the chromosomal constitution of the excluded cells.

Preimplantation genetic testing in the current era, a review.

BACKGROUND: Preimplantation genetic testing (PGT), also referred to as preimplantation genetic diagnosis (PGD), is an advanced reproductive technology used during in vitro fertilization (IVF) cycles to identify genetic abnormalities in embryos prior to their implantation. PGT is used to screen embryos for chromosomal abnormalities, monogenic disorders, and structural rearrangements. DEVELOPMENT OF PGT: Over the past few decades, PGT has undergone tremendous development, resulting in three primary forms: PGT-A, PGT-M, and PGT-SR. PGT-A is utilized for screening embryos for aneuploidies, PGT-M is used to detect disorders caused by a single gene, and PGT-SR is used to detect chromosomal abnormalities caused by structural rearrangements in the genome. PURPOSE OF REVIEW: In this review, we thoroughly summarized and reviewed PGT and discussed its pros and cons down to the minutest aspects. Additionally, recent studies that highlight the advancements of PGT in the current era, including their future perspectives, were reviewed. CONCLUSIONS: This comprehensive review aims to provide new insights into the understanding of techniques used in PGT, thereby contributing to the field of reproductive genetics.

Agarose amplification based sequencing characterization cell-free RNA in preimplantation spent embryo medium.

BACKGROUND: The cell-free RNA (cf-RNA) of spent embryo medium (SEM) has aroused a concern of academic and clinical researchers for its potential use in non-invasive embryo screening. However, comprehensive characterization of cf-RNA from SEM still presents significant technical challenges, primarily due to the limited volume of SEM. Hence, there is urgently need to a small input liquid volume and ultralow amount of cf-RNA library preparation method to unbiased cf-RNA sequencing from SEM. (75) RESULT: Here, we report a high sensitivity agarose amplification-based cf-RNA sequencing method (SEM-Acf) for human preimplantation SEM cf-RNA analysis. It is a cf-RNA sequencing library preparation method by adding agarose amplification. The agarose amplification sensitivity (0.005 pg) and efficiency (105.35 %) were increased than that of without agarose addition (0.45 pg and 96.06 %) by âˆ¼ 90 fold and 9.29 %, respectively. Compared with SMART sequencing (SMART-seq), the correlation of gene expression was stronger in different SEM samples by using SEM-Acf. The cf-RNA number of detected and coverage uniformity of 3' end were significantly increased. The proportion of 5' end adenine, alternative splicing events and short fragments (<400 bp) were increased. It is also found that 4-mer end motifs of cf-RNA fragments was significantly differences between different embryonic stage by day3 spent cleavage medium and day5/6 spent blastocyst medium. (141) SIGNIFICANCE: This study established an efficient SEM amplification and library preparation method. Additionally, we successfully described the characterizations of SEM cf-RNA in preimplantation embryo using SEM-Acf, including expression features and fragment lengths. SEM-Acf facilitates the exploration of cf-RNA as a noninvasive embryo screening biomarker, and opens up potential clinical utilities of small input liquid volume and ultralow amount cf-RNA sequencing. (59).

To transfer or not to transfer: the dilemma of mosaic embryos - a narrative review.

A frequent finding after preimplantation genetic diagnostic testing for aneuploidies using next-generation sequencing is an embryo that is putatively mosaic. The prevalence of this outcome remains unclear and varies with technical and external factors. Mosaic embryos can be classified by the percentage of cells affected, type of chromosome involvement (whole or segmental), number of affected chromosomes or affected cell type (inner mass cell, trophectoderm or both). The origin of mosaicism seems to be intrinsic as a post-zygotic mitotic error, but some external factors can play a role. As experience has increased with the transfer of mosaic embryos, clinical practice has gradually become more flexible in recent years. Nevertheless, clinical results show lower implantation, pregnancy and clinical pregnancy rates and higher miscarriage rates with mosaic embryo transfer when compared with the transfer of euploid embryos. Prenatal diagnosis is highly recommended after the transfer of mosaic embryos. This narrative review is intended to serve as reference material for practitioners in reproductive medicine who must manage a mosaic embryo result after preimplantation genetic testing for aneuploidies.