Exploring attitudes and experiences with reproductive genetic carrier screening among couples seeking medically assisted reproduction: a longitudinal survey study.

PURPOSE: This study aimed to assess the attitudes and experiences of subfertile couples applying for medically assisted reproduction (MAR) using their own gametes towards reproductive genetic carrier screening (RGCS) for monogenic conditions. METHODS: A prospective survey study was conducted where subfertile couples were recruited from the fertility centre of a university hospital in Flanders, Belgium. Participants were offered RGCS free of charge and completed self-administered questionnaires at three different time points. RESULTS: The study sample consisted of 26 couples. Most participants had no children, did not consider themselves as religious, and had some form of higher education. Overall, attitudes towards RGCS were mostly positive and the intention to participate in RGCS was high. Anxiety scores were only elevated and clinically relevant for a limited number of participants. A large proportion of participants would consider preventive reproductive options like prenatal diagnosis or in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) combined with pre-implantation genetic testing for monogenic conditions (PGT-M) in the event of an increased likelihood of conceiving a child with a hereditary condition. Participants were satisfied with their decision to undergo RGCS, and the majority would recommend RGCS to other couples. CONCLUSION: Our study findings suggest that subfertile couples applying for MAR using their own gametes find RGCS acceptable and have a positive attitude towards it. This study provides valuable insights into the perspectives of these couples, highlighting the need for appropriate counseling and timely information provision.

Impact of Indication for Oocyte and Embryo Reception on Reproductive and Obstetric Outcomes.

OBJECTIVES: This study aimed to assess if the indication for oocyte reception (OR) or embryo reception (ER) impacts the reproductive and obstetric outcomes by evaluating our experience at a tertiary fertility centre and by performing a literature review on this subject. Several previous studies have reported that, in contrast to other types of fertility treatment, the indication for OR/ER seems to have little impact on the outcomes. However, the compared indication groups vary considerably between these studies, and some data indicates worse outcomes in patients who developed premature ovarian insufficiency (POI) due to Turner syndrome or treatment with chemotherapy/radiotherapy. DESIGN: A retrospective analysis of all cases of OR/ER at a tertiary fertility centre from 2001 until 2020 was conducted. We analysed 584 cycles from 194 individual patients. A literature review on the impact of indication on reproductive or obstetric outcomes of OR/ER was performed using the following databases: PubMed/MEDLINE, Embase, and the Cochrane Library. A total of 27 studies were included and analysed. PARTICIPANTS, SETTING, METHODS: For the retrospective analysis, patients were divided into three major indication groups: failure of autologous assisted reproductive technology, POI, and genetic disease carrier. To assess reproductive outcomes, we determined pregnancy rate, implantation rate, miscarriage rate, and live birth rate. For comparing obstetric outcomes, we reviewed the term of birth, mode of delivery, and birthweight. Outcomes were compared using Fisher's exact test, χ2 test, and one-way ANOVA utilizing the GraphPad tool. RESULTS: There were no significant differences in reproductive and obstetric outcomes between the three major indication groups in our population, in line with the findings reported by existing literature. Data on impaired reproductive outcomes in patients with POI after chemotherapy/radiotherapy are conflicting. Obstetrically, these patients are at higher risk of preterm birth and possibly also low birthweight, especially after abdomino-pelvic or total body irradiation. For patients with POI due to Turner syndrome, most data suggest similar pregnancy rates but a higher rate of pregnancy loss, and obstetrically an increased risk of hypertensive disorders and caesarean section. LIMITATIONS: The small number of patients in the retrospective analysis resulted in low statistical power when evaluating differences between smaller subgroups. There were some missing data on the occurrence of complications during pregnancy. Our analysis covers a period of 20 years, during which several technological innovations have also been made. CONCLUSIONS: Our study shows that the important heterogeneity in couples treated with OR/ER does not significantly impact their reproductive or obstetric outcomes, except for POI due to Turner syndrome or treatment with chemotherapy/radiotherapy, where there seems to be an important uterine/endometrial component that cannot be entirely overcome by providing a healthy oocyte.

Protease secretions by the invading blastocyst induce calcium oscillations in endometrial epithelial cells via the protease-activated receptor 2.

BACKGROUND: Early embryo implantation is a complex phenomenon characterized by the presence of an implantation-competent blastocyst and a receptive endometrium. Embryo development and endometrial receptivity must be synchronized and an adequate two-way dialogue between them is necessary for maternal recognition and implantation. Proteases have been described as blastocyst-secreted proteins involved in the hatching process and early implantation events. These enzymes stimulate intracellular calcium signaling pathways in endometrial epithelial cells (EEC). However, the exact molecular players underlying protease-induced calcium signaling, the subsequent downstream signaling pathways and the biological impact of its activation remain elusive. METHODS: To identify gene expression of the receptors and ion channels of interest in human and mouse endometrial epithelial cells, RNA sequencing, RT-qPCR and in situ hybridization experiments were conducted. Calcium microfluorimetric experiments were performed to study their functional expression. RESULTS: We showed that trypsin evoked intracellular calcium oscillations in EEC of mouse and human, and identified the protease-activated receptor 2 (PAR2) as the molecular entity initiating protease-induced calcium responses in EEC. In addition, this study unraveled the molecular players involved in the downstream signaling of PAR2 by showing that depletion and re-filling of intracellular calcium stores occurs via PLC, IP3R and the STIM1/Orai1 complex. Finally, in vitro experiments in the presence of a specific PAR2 agonist evoked an upregulation of the 'Window of implantation' markers in human endometrial epithelial cells. CONCLUSIONS: These findings provide new insights into the blastocyst-derived protease signaling and allocate a key role for PAR2 as maternal sensor for signals released by the developing blastocyst.

Experiences of nonpregnant couples after receiving reproductive genetic carrier screening results in Belgium.

Reproductive genetic carrier screening (RGCS) allows for the identification of couples who have an increased likelihood of conceiving a child with a particular autosomal recessive or X-linked condition. The aim of this study was to assess the level of satisfaction, anxiety, knowledge retention, psychosocial and counseling-related aspects among couples who chose to have RGCS. Participants were initially informed about their screening results by telephone. After obtaining a written report of test results, participants were asked to complete an individual self-administered questionnaire. All participants (n = 67) felt they had enough information to make an informed choice. None of the participants regretted their choice to have RGCS. Test results were most often shared with parents (61%) or siblings (37%). Our findings demonstrate that the information/counseling and reporting strategy that was used in the context of this study led to high participant satisfaction, an increase in knowledge over time and favorable psychosocial and counseling-related outcomes.

The Impact of Chronic Endometritis on Infertility: Prevalence, Reproductive Outcomes, and the Role of Hysteroscopy as a Screening Tool.

OBJECTIVES: The objective of this study was to examine the prevalence of chronic endometritis (CE) in infertile women, its impact on reproductive outcomes, and the accuracy of hysteroscopy as a screening tool for CE. DESIGN: This was a prospective observational study. PARTICIPANTS: Participants involved in this study were 514 asymptomatic patients with infertility. SETTING: The review was conducted in a tertiary care center. METHODS: The participants underwent a hysteroscopy and endometrial biopsy (EMB). Antibiotics were given for cases of CE. We investigated the prevalence of CE in patients starting assisted reproductive technologies (ART) as a primary outcome. Secondary outcomes were the clinical pregnancy rate (CPR) in the ART cycle after hysteroscopy, EMB, and antibiotic treatment in cases of CE; the cumulative CPR in the subsequent 2 years after hysteroscopy and EMB; the sensitivity and specificity of hysteroscopy as a screening tool compared to EMB as the "gold standard" for diagnosing CE. RESULTS: CE was identified in 2.8% of patients starting ART (11/393). CPRs did not differ significantly between patients with CE and the entire cohort of patients without CE in the subsequent ART cycle (OR: 0.43; 95% CI: 0.09-2.02) or in the 2 years after EMB (OR: 0.56; 95% CI: 0.16-1.97). In a matched control comparison (with matching for age, basal FSH, and cause of infertility), CPR in patients with CE did not differ in the subsequent ART cycle (OR: 0.39; 95% CI: 0.09-1.61); however, their CPR in the 2 years after EMB was significantly lower (OR: 0.22; 95% CI: 0.13-0.38). The sensitivity and specificity of hysteroscopy as a screening tool for diagnosing CE were 8.3% and 90.1%, respectively. LIMITATIONS: Due to our cohort's low CE prevalence, we could not detect significant differences in CPRs. CONCLUSION: CE is rare in our studied population of asymptomatic patients starting ART. Hysteroscopy cannot replace EMB for diagnosing CE.

Preclinical workup using long-read amplicon sequencing provides families with de novo pathogenic variants access to universal preimplantation genetic testing.

STUDY QUESTION: Can long-read amplicon sequencing be beneficial for preclinical preimplantation genetic testing (PGT) workup in couples with a de novo pathogenic variant in one of the prospective parents? SUMMARY ANSWER: Long-read amplicon sequencing represents a simple, rapid and cost-effective preclinical PGT workup strategy that provides couples with de novo pathogenic variants access to universal genome-wide haplotyping-based PGT programs. WHAT IS KNOWN ALREADY: Universal PGT combines genome-wide haplotyping and copy number profiling to select embryos devoid of both familial pathogenic variants and aneuploidies. However, it cannot be directly applied in couples with a de novo pathogenic variant in one of the partners due to the absence of affected family members required for phasing the disease-associated haplotype. STUDY DESIGN, SIZE, DURATION: This is a prospective study, which includes 32 families that were enrolled in the universal PGT program at the University Hospital of Leuven between 2018 and 2022. We implemented long-read amplicon sequencing during the preclinical PGT workup to deduce the parental origin of the disease-associated allele in the affected partner, which can then be traced in embryos during clinical universal PGT cycles. PARTICIPANTS/MATERIALS, SETTING, METHODS: To identify the parental origin of the disease-associated allele, genomic DNA from the carrier of the de novo pathogenic variant and his/her parent(s) was used for preclinical PGT workup. Primers flanking the de novo variant upstream and downstream were designed for each family. Following long-range PCR, amplicons that ranged 5-10 kb in size, were sequenced using Pacific Bioscience and/or Oxford Nanopore platforms. Next, targeted variant calling and haplotyping were performed to identify parental informative single-nucleotide variants (iSNVs) linked to the de novo mutation. Following the preclinical PGT workup, universal PGT via genome-wide haplotyping was performed for couples who proceeded with clinical PGT cycle. In parallel, 13 trophectoderm (TE) biopsies from three families that were analyzed by universal PGT, were also used for long-read amplicon sequencing to explore this approach for embryo direct mutation detection coupled with targeted long-read haplotyping. MAIN RESULTS AND THE ROLE OF CHANCE: The parental origin of the mutant allele was identified in 24/32 affected individuals during the preclinical PGT workup stage, resulting in a 75% success rate. On average, 5.95 iSNVs (SD = 4.5) were detected per locus of interest, and the average distance of closest iSNV to the de novo variant was ∼1750 bp. In 75% of those cases (18/24), the de novo mutation occurred on the paternal allele. In the remaining eight families, the risk haplotype could not be established due to the absence of iSNVs linked to the mutation or inability to successfully target the region of interest. During the time of the study, 12/24 successfully analyzed couples entered the universal PGT program, and three disease-free children have been born. In parallel to universal PGT analysis, long-read amplicon sequencing of 13 TE biopsies was also performed, confirming the segregation of parental alleles in the embryo and the results of the universal PGT. LIMITATIONS, REASONS FOR CAUTION: The main limitation of this approach is that it remains targeted with the need to design locus-specific primers. Because of the restricted size of target amplicons, the region of interest may also remain non-informative in the absence of iSNVs. WIDER IMPLICATIONS OF THE FINDINGS: Targeted haplotyping via long-read amplicon sequencing, particularly using Oxford Nanopore Technologies, provides a valuable alternative for couples with de novo pathogenic variants that allows access to universal PGT. Moreover, the same approach can be used for direct mutation analysis in embryos, as a second line confirmation of the preclinical PGT result or as a potential alternative PGT procedure in couples, where additional family members are not available. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by KU Leuven funding (no. C1/018 to J.R.V.) and Fonds Wetenschappelijk Onderzoek (1241121N to O.T.). J.R.V. is co-inventor 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. All other authors have no conflict of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Parental genomes segregate into distinct blastomeres during multipolar zygotic divisions leading to mixoploid and chimeric blastocysts.

BACKGROUND: During normal zygotic division, two haploid parental genomes replicate, unite and segregate into two biparental diploid blastomeres. RESULTS: Contrary to this fundamental biological tenet, we demonstrate here that parental genomes can segregate to distinct blastomeres during the zygotic division resulting in haploid or uniparental diploid and polyploid cells, a phenomenon coined heterogoneic division. By mapping the genomic landscape of 82 blastomeres from 25 bovine zygotes, we show that multipolar zygotic division is a tell-tale of whole-genome segregation errors. Based on the haplotypes and live-imaging of zygotic divisions, we demonstrate that various combinations of androgenetic, gynogenetic, diploid, and polyploid blastomeres arise via distinct parental genome segregation errors including the formation of additional paternal, private parental, or tripolar spindles, or by extrusion of paternal genomes. Hence, we provide evidence that private parental spindles, if failing to congress before anaphase, can lead to whole-genome segregation errors. In addition, anuclear blastomeres are common, indicating that cytokinesis can be uncoupled from karyokinesis. Dissociation of blastocyst-stage embryos further demonstrates that whole-genome segregation errors might lead to mixoploid or chimeric development in both human and cow. Yet, following multipolar zygotic division, fewer embryos reach the blastocyst stage and diploidization occurs frequently indicating that alternatively, blastomeres with genome-wide errors resulting from whole-genome segregation errors can be selected against or contribute to embryonic arrest. CONCLUSIONS: Heterogoneic zygotic division provides an overarching paradigm for the development of mixoploid and chimeric individuals and moles and can be an important cause of embryonic and fetal arrest following natural conception or IVF.

The needs of subfertile couples continuing to attempt natural conception: in-depth interviews.

STUDY QUESTION: What are the experiences and the support and sexual advice needs of subfertile couples continuing to attempt natural conception after the diagnostic fertility work-up? SUMMARY ANSWER: Exploration of the experiences of couples showed that couples would have appreciated fertility clinic staff embedding expectant management into the fertility clinic trajectory, supportive staff with female and male patient interactions and advice on common experiences of peers and on managing their lifestyle, distress and subfertility-related sexual challenges. WHAT IS KNOWN ALREADY: Dutch and British professional guidelines advise newly diagnosed subfertile couples with a 'good prognosis' to continue to attempt natural conception and do not require fertility clinic staff to interact with patients. Fertility clinic staff and subfertile couples struggle to follow these guidelines as they feel an urgent need for action. Subfertile couples might benefit from sexual advice, as subfertility is negatively associated with sexual functioning, which is important for natural conception. STUDY DESIGN SIZE DURATION: Twelve one-time in-depth interviews (2015-2017) were conducted with 10 heterosexual couples and 2 women whose partners did not participate, then the interviews were subjected to inductive content analysis, reaching inductive thematic saturation. PARTICIPANTS/MATERIALS SETTING METHODS: The 22 interviewees had experienced 3-18 months of expectant management after their diagnostic fertility work-up in a Belgian or a Dutch tertiary fertility clinic. The face-to-face in-depth interviews explored positive and negative experiences and unmet needs. The transcribed interviews were subjected to inductive content analysis, by two researchers discussing initial disagreements. MAIN RESULTS AND THE ROLE OF CHANCE: Couples would appreciate fertility clinic staff embedding expectant management in the fertility clinic trajectory, by starting off with reassuring couples that their very thorough diagnostic fertility work-up demonstrated their good chance of natural conception, and by involving couples in deciding on the duration of expectant management and by planning the follow-up appointment after expectant management up front. Couples had encountered sexual challenges during expectant management and had an interest in sexual advice, focused on increasing pleasure and partner bonding and preventing the rise of dysfunctions. The couples agreed that a (secured) website with evidence-based, non-patronizing text and mixed media would be an appropriate format for a novel support programme. Couples were keen for interactions with fertility clinic staff which addressed both partners of subfertile couples. Couples also valued advice on managing their lifestyle and distress and would have liked information on the experiences of their peers. LIMITATIONS REASONS FOR CAUTION: Recall bias is plausible given the retrospective nature of this study. This explorative interview study was not designed for examining country or gender differences in experiences and needs but it did generate new findings on inter-country differences. WIDER IMPLICATIONS OF THE FINDINGS: Rather than simply advising expectant management, fertility clinics are encouraged to offer couples who continue to attempt natural conception after their diagnostic fertility work-up, supportive patient-staff interactions with advice on common experiences of peers and on managing their lifestyle, distress and sexual challenges related to subfertility. STUDY FUNDING/COMPETING INTERESTS: Funded by Flanders Research Foundation and the University of Amsterdam. There are no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Exploring informed choice in preconception reproductive genetic carrier screening by using a modified Multidimensional Measure of Informed Choice.

OBJECTIVES: To explore informed choice in reproductive genetic carrier screening (RGCS). METHODS: Women visiting a gynaecologist practice in Flanders (Belgium) were asked to consider participation in a study where RGCS was offered for free to them and their male partner. A modified Multidimensional Measure of Informed Choice was used to determine whether couples who opted for RGCS made an informed choice. In addition, we assessed risk perception, feelings towards RGCS, anxiety and decisional conflict. RESULTS: Most participants (82 %, n = 63/77) made an informed choice with regard to RGCS according to our modified MMIC. Thirteen participants made an uninformed choice due to insufficient knowledge and one participant because of insufficient knowledge and value-inconsistency. Anxiety scores were elevated for three participants. Two participants presented with decisional conflict. CONCLUSION: Our results show high rates of informed choice among non-pregnant couples who were offered RGCS in a research study and received up to 30 min of pre-test counseling. PRACTICE IMPLICATIONS: Limited resources outside a research context may impact informed choice. Pre-test counselling initiatives for RGCS should ideally be organized in such a way that information can be provided at multiple time points to avoid information overload and to allow for a reflection period.

Reasons affecting the uptake of reproductive genetic carrier screening among nonpregnant reproductive-aged women in Flanders (Belgium).

Reproductive genetic carrier screening (RGCS) allows to identify couples who have an increased likelihood of conceiving a child affected with an autosomal recessive or X-linked monogenic condition. Multiple studies have reported on a wide and fragmented set of reasons to accept or decline RGCS. Only a few studies have been performed to assess the uptake of RGCS. Nonpregnant women visiting their gynecologist were invited to complete a questionnaire assessing perceived susceptibility, the acceptability of offering RGCS, attitudes, the intention to participate in RGCS, reasons to accept or decline RGCS, and sociodemographic characteristics. Women who showed the intention to have RGCS were asked to consider a free RGCS offer. Most women (n = 127) were between 25 and 34 years old (60%), in a relationship (91%), and wanted to have children (65%). Study participants had positive attitudes towards RGCS and the intention to consider RGCS in the future. Reasons to accept RGCS were being able to share genetic information with children or relatives (n = 104/127, 82%), to prevent the birth of a child affected with a hereditary condition (n = 103/127, 81%), and/or to know the chance of conceiving a child with a hereditary condition (n = 102/127, 80%). Reasons for declining RGCS were the possible concerns that could arise when receiving test results (n = 27/127, 21%), having no family history of hereditary disorders (n = 19/127, 15%), and not wanting to take action based on test results (n = 13/127, 10%). Among test intenders that met the inclusion criteria, 53% decided to participate in RGCS together with their male reproductive partner. More in-depth research on the decision-making process behind the choice to accept or decline an RGCS offer would be highly valuable to make sure couples are making informed reproductive choices.

Knowledge, attitudes and preferences regarding reproductive genetic carrier screening among reproductive-aged men and women in Flanders (Belgium).

Through carrier screening couples at-risk of conceiving a child with an autosomal recessive or X-linked condition can be identified prior to conception. The aim of this study was to assess knowledge, attitudes and preferences regarding reproductive genetic carrier screening (RGCS) among reproductive-aged men and women in Flanders (Belgium). Women and men of reproductive age visiting their pharmacist were invited to answer a self-administered questionnaire. Prior to filling in the questionnaire, participants were asked to read an information leaflet explaining some key concepts about RGCS. Our sample included 387 individuals of reproductive age, of which 68.5% were female and 31.5% were male. Most of the participants were below 34 years old (72.9%), didn't have children (68.6%) and were currently in a relationship (69.1%). Offering RGCS to couples that want to have children was found acceptable by 86% of participants. However, fewer participants would consider RGCS for themselves in the future (61%). We observed a positive correlation between attitude score/knowledge score and the intention to have RGCS. Half of the participants (50.9%) preferred the disclosure of individual test results. Most of participants indicated that RGCS should be offered through the gynecologist (81.1%), followed by the GP (71.5%) and the Centre for Human Genetics (64.8%). About 68.9% of participants were willing to pay out-of-pocket for an RGCS test. We recommend that RGCS should ideally be implemented through a tailored implementation strategy whereby individual needs and preferences can be taken into account.

Single-cell genome-wide concurrent haplotyping and copy-number profiling through genotyping-by-sequencing.

Single-cell whole-genome haplotyping allows simultaneous detection of haplotypes associated with monogenic diseases, chromosome copy-numbering and subsequently, has revealed mosaicism in embryos and embryonic stem cells. Methods, such as karyomapping and haplarithmisis, were deployed as a generic and genome-wide approach for preimplantation genetic testing (PGT) and are replacing traditional PGT methods. While current methods primarily rely on single-nucleotide polymorphism (SNP) array, we envision sequencing-based methods to become more accessible and cost-efficient. Here, we developed a novel sequencing-based methodology to haplotype and copy-number profile single cells. Following DNA amplification, genomic size and complexity is reduced through restriction enzyme digestion and DNA is genotyped through sequencing. This single-cell genotyping-by-sequencing (scGBS) is the input for haplarithmisis, an algorithm we previously developed for SNP array-based single-cell haplotyping. We established technical parameters and developed an analysis pipeline enabling accurate concurrent haplotyping and copy-number profiling of single cells. We demonstrate its value in human blastomere and trophectoderm samples as application for PGT for monogenic disorders. Furthermore, we demonstrate the method to work in other species through analyzing blastomeres of bovine embryos. Our scGBS method opens up the path for single-cell haplotyping of any species with diploid genomes and could make its way into the clinic as a PGT application.

TRP channel expression correlates with the epithelial-mesenchymal transition and high-risk endometrial carcinoma.

Transient receptor potential (TRP) channels excel in cellular sensing as they allow rapid ion influx across the plasma membrane in response to a variety of extracellular cues. Recently, a distinct TRP mRNA expression signature was observed in stromal cells (ESC) and epithelial cells (EEC) of the endometrium, a tissue in which cell phenotypic plasticity is essential for normal functioning. However, it is unknown whether TRP channel mRNA expression is subject to the phenotypic switching that occurs during epithelial to mesenchymal transition (EMT) and mesenchymal to epithelial transition (MET), and whether TRP channel mRNA expression is associated with aggressive phenotypes in endometrial cancer (EC). Here, we induced EMT and MET in vitro using in primary EEC and ESC, respectively, and analyzed expression and functionality of TRP channels using RT-qPCR and intracellular Ca2+ imaging. The outcome of these experiments showed a strong association between TRPV2 and TRPC1 mRNA expression and the mesenchymal phenotype, whereas TRPM4 mRNA expression correlated with the epithelial phenotype. In line herewith, increased TRPV2 and TRPC1 mRNA expression levels were observed in both primary and metastatic EC biopsies and in primary EC cells with a high EMT status, indicating an association with an aggressive tumor phenotype. Remarkably, TRPV2 mRNA expression in primary EC biopsies was associated with tumor invasiveness and cancer stage. In contrast, increased TRPM4 mRNA expression was observed in EC biopsies with a low EMT status and less aggressive tumor phenotypes. Taken together, this dataset proved for the first time that TRP channel mRNA expression is strongly linked to cellular phenotypes of the endometrium, and that phenotypic transitions caused by either experimental manipulation or malignancy could alter this expression in a predictable manner. These results implicate that TRP channels are viable biomarkers to identify high-risk EC, and potential targets for EC treatment.

Haplotyping-based preimplantation genetic testing reveals parent-of-origin specific mechanisms of aneuploidy formation.

Chromosome instability is inherent to human IVF embryos, but the full spectrum and developmental fate of chromosome anomalies remain uncharacterized. Using haplotyping-based preimplantation genetic testing for monogenic diseases (PGT-M), we mapped the parental and mechanistic origin of common and rare genomic abnormalities in 2300 cleavage stage and 361 trophectoderm biopsies. We show that while single whole chromosome aneuploidy arises due to chromosome-specific meiotic errors in the oocyte, segmental imbalances predominantly affect paternal chromosomes, implicating sperm DNA damage in segmental aneuploidy formation. We also show that postzygotic aneuploidy affects multiple chromosomes across the genome and does not discriminate between parental homologs. In addition, 6% of cleavage stage embryos demonstrated signatures of tripolar cell division with excessive chromosome loss, however hypodiploid blastomeres can be excluded from further embryo development. This observation supports the selective-pressure hypothesis in embryos. Finally, considering that ploidy violations may constitute a significant proportion of non-viable embryos, using haplotyping-based approach to map these events might further improve IVF success rate.

Expanded carrier screening in Flanders (Belgium): an online survey on the perspectives of nonpregnant reproductive-aged women.

Aim: Despite a considerable interest in expanded carrier screening (ECS) in the general population, actual uptake of ECS remains low. More insights are needed to better understand the perspectives of reproductive-aged individuals. Materials & methods: Nonpregnant women of reproductive age recruited through public pharmacies throughout Flanders (Belgium) were invited to participate in an online survey. Results: Most participants (63.6%) indicated they would consider ECS for themselves in the future. About one in two participants showed a positive attitude toward ECS. Conclusion: This study reports valuable insights in the perspectives of nonpregnant reproductive-aged women in Flanders (Belgium) regarding ECS that can be used in the ongoing debate on the responsible implementation of ECS.

Lay abstract Previous studies have reported a considerable interest in carrier screening for hereditary conditions among individuals in the general population, but actual uptake remains low. This study examines the perspectives of nonpregnant reproductive-aged women in Flanders (Belgium) regarding expanded carrier screening (ECS) for hereditary conditions to gain more insights in factors that possibly influence the opinions of reproductive-aged women. These insights are crucial to ensure a responsible implementation of ECS within healthcare services and to make sure that future parents are making informed choices when they are presented with the choice to accept or decline ECS. The results of this study can be used by healthcare providers interacting with couples planning a pregnancy to improve pre-/post-test counseling services. Which in turn can help to manage expectations and reduce misconceptions among potential users of ECS.

Mapping the expression of transient receptor potential channels across murine placental development.

Transient receptor potential (TRP) channels play prominent roles in ion homeostasis by their ability to control cation influx. Mouse placentation is governed by the processes of trophoblast proliferation, invasion, differentiation, and fusion, all of which require calcium signaling. Although certain TRP channels have been shown to contribute to maternal-fetal transport of magnesium and calcium, a role for TRP channels in specific trophoblast functions has been disregarded. Using qRT-PCR and in situ hybridisation, the spatio-temporal expression pattern of TRP channels in the mouse placenta across gestation (E10.5-E18.5) was assessed. Prominent expression was observed for Trpv2, Trpm6, and Trpm7. Calcium microfluorimetry in primary trophoblast cells isolated at E14.5 of gestation further revealed the functional activity of TRPV2 and TRPM7. Finally, comparing TRP channels expression in mouse trophoblast stem cells (mTSCs) and mouse embryonic stem cells (mESC) confirmed the specific expression of TRPV2 during placental development. Moreover, TRP channel expression was similar in mTSCs compared to primary trophoblasts and validate mTSC as a model to study TRP channels in placental development. Collectivity, our results identify a specific spatio-temporal TRP channel expression pattern in trophoblasts, suggesting a possible involvement in regulating the process of placentation.

Predicting the chance on live birth per cycle at each step of the IVF journey: external validation and update of the van Loendersloot multivariable prognostic model.

OBJECTIVE: To study the performance of the 'van Loendersloot' prognostic model for our clinic's in vitro fertilisation (IVF) in its original version, the refitted version and in an adapted version replacing previous by current cycle IVF laboratory variables. METHODS: This retrospective cohort study in our academic tertiary fertility clinic analysed 1281 IVF cycles of 591 couples, who completed at least one 2nd-6th IVF cycle with own fresh gametes after a previous IVF cycle with the same partner in our clinic between 2010 and 2018. The outcome of interest was the chance on a live birth after one complete IVF cycle (including all fresh and frozen embryo transfers from the same episode of ovarian stimulation). Model performance was expressed in terms of discrimination (c-statistics) and calibration (calibration model, comparison of prognosis to observed ratios of five disjoint groups formed by the quintiles of the IVF prognoses and a calibration plot). RESULTS: A total of 344 live births were obtained (26.9%). External validation of the original van Loendersloot model showed a poor c-statistic of 0.64 (95% CI: 0.61 to 0.68) and an underestimation of IVF success. The refitted and the adapted models showed c-statistics of respectively 0.68 (95% CI: 0.65 to 0.71) and 0.74 (95% CI: 0.70 to 0.77). Similar c-statistics were found with cross-validation. Both models showed a good calibration model; refitted model: intercept=0.00 (95% CI: -0.23 to 0.23) and slope=1.00 (95% CI: 0.79 to 1.21); adapted model: intercept=0.00 (95% CI: -0.18 to 0.18) and slope=1.00 (95% CI: 0.83 to 1.17). Prognoses and observed success rates of the disjoint groups matched well for the refitted model and even better for the adapted model. CONCLUSION: External validation of the original van Loendersloot model indicated that model updating was recommended. The good performance of the refitted and adapted models allows informing couples about their IVF prognosis prior to an IVF cycle and at the time of embryo transfer. Whether this has an impact on couple's expected success rates, distress and IVF discontinuation can now be studied.

Identity-by-state-based haplotyping expands the application of comprehensive preimplantation genetic testing.

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.

Interest in expanded carrier screening among individuals and couples in the general population: systematic review of the literature.

BACKGROUND: Through carrier screening, prospective parents can acquire information about whether they have an increased risk of conceiving a child affected with an autosomal recessive or X-linked condition. Within the last decade, advances in genomic technologies have facilitated a shift from condition-directed carrier screening to expanded carrier screening (ECS). Following the introduction of ECS, several studies have been performed to gauge the interest in this new technology among individuals and couples in the general population. OBJECTIVE AND RATIONALE: The aim of this systematic review was to synthesize evidence from empirical studies that assess the interest in ECS among individuals and couples in the general population. As the availability and accessibility of ECS grow, more couples who are a priori not at risk based on their personal or family history will be presented with the choice to accept or decline such an offer. Their attitudes and beliefs, as well as the perceived usefulness of this screening modality, will likely determine whether ECS is to become a widespread reproductive genetic test. SEARCH METHODS: Four databases (Pubmed, Web of Science, CINAHL, Cochrane Library) were systematically searched to identify English language studies performed between January 2009 and January 2019 using the following search terms: carrier screening, carrier testing, attitudes, intention, interest, views, opinions, perspectives and uptake. Studies were eligible for inclusion if they reported on intentions to undergo a (hypothetical) ECS test, uptake of an actual ECS offer or both. Two researchers performed a multistep selection process independently for validation purposes. OUTCOMES: Twelve empirical studies performed between 2015 and 2019 were included for analysis. The studies originated from the USA (n = 6), the Netherlands (n = 3), Belgium (n = 1), Sweden (n = 1) and Australia (n = 1). The sample size of the studies varied from 80 to 1669. In the included studies, 32%-76% of respondents were interested in a (hypothetical) ECS test, while uptake rates for actual ECS offers ranged from 8% to 50%. The highest overall uptake was observed when ECS was offered to pregnant women (50%). By contrast, studies focusing on the preconception population reported lower overall uptake rates (8-34%) with the exception of one study where women were counseled preconception in preparation for IVF (68.7%). WIDER IMPLICATIONS: Our findings suggest that there may be discrepancies between prospective parents' reported intentions to undergo ECS and their actual uptake, particularly during the preconception period. As ECS is a new and relatively unknown test for most future parents, the awareness and comprehension within the general population could be rather limited. Adequate pre- and post-test counseling services should be made available to couples offered ECS to ensure informed reproductive decision-making, together with guidelines for primary health care professionals. Due to restricted nature of the samples and methods of the underlying primary studies, some of the reported results might not be transferable to a broader population. More research is needed to see if the observed trends also apply to a broader and more diverse population.

Effectiveness of a mobile preconception lifestyle programme in couples undergoing in vitro fertilisation (IVF): the protocol for the PreLiFe randomised controlled trial (PreLiFe-RCT).

INTRODUCTION: Infertility and in vitro fertilisation (IVF; with or without intracytoplasmic sperm injection) result in considerable emotional and financial burden. Increasing evidence suggests that lifestyle factors, including diet, physical activity and personal well-being, are associated with IVF-success rates. Currently, IVF is not routinely combined with a lifestyle programme. The preconception lifestyle (PreLiFe) randomised controlled trial (RCT) assesses the effects of a new mobile PreLiFe programme in couples undergoing IVF. METHODS AND ANALYSIS: A multicentre RCT including 460 heterosexual couples starting IVF in Belgian fertility clinics. IVF couples are randomised between an attention control group or the PreLiFe programme for a period of 12 months or until an ongoing pregnancy is confirmed by ultrasound. The attention control programme includes a mobile application with treatment information (ie, appointments and medication instructions) in addition to standard care. The PreLiFe programme includes a mobile application with the same treatment information in combination with a lifestyle programme. This new lifestyle programme includes tailored advice and skills training on diet, physical activity and mindfulness in combination with text messages and telephone interaction with a healthcare professional trained in motivational interviewing. The primary outcome of this RCT is the cumulative ongoing pregnancy rate within 12 months after randomisation. Secondary outcomes include changes in diet, physical activity, emotional distress, body mass index, waist circumference, quality of life and other reproductive outcomes including IVF discontinuation, clinical pregnancy rate and time to pregnancy. Additionally, partner support and the feasibility (use and acceptability) of the PreLiFe programme will be evaluated in the intervention group. Analysis will be according to intention to treat. ETHICS AND DISSEMINATION: This study has been approved by the Medical Ethical Committee of the Leuven University Hospital (Belgium) and the other recruiting clinics. The findings of this RCT will be disseminated through presentations at international scientific meetings and peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT03790449; Pre-results.