Culture time to optimize embryo cell-free DNA (cfDNA) analysis for frozen-thawed blastocysts undergoing non-invasive preimplantation genetic testing for aneuploidy (niPGT-A).

OBJECTIVE: Cell-free DNA (cfDNA) is released into the spent blastocyst media (spent media) by the embryo. However, optimal timing to determine maximal cfDNA in the case of frozen-thawed blastocysts undergoing non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) remains to be elucidated. In the current study we investigated the ideal time in culture to optimize embryo cell-free DNA (cfDNA) analysis in frozen-thawed blastocysts undergoing niPGT-A. DESIGN: In this prospective observational study, 135 spent media and corresponding whole blastocysts were collected from January 2021 through March 2022. SUBJECTS: Day-5 frozen-thawed blastocysts were cultured for 8 hours (Day-5 Short) or 24 hours (Day-5 Long), while day-6 frozen-thawed blastocysts were cultured for 8 hours (Day-6 Short). The spent media and whole blastocysts were then collected for further analysis. Spent media and whole blastocysts were amplified using whole genome amplification (WGA) and sequenced using Next Generation Sequencing (NGS). MAIN OUTCOME MEASURES: Informativity and concordance rates between cfDNA in spent media and whole blastocysts DNA were compared according to the different time in culture. RESULTS: When comparing time in culture, informativity rates for spent media were significantly higher (p<0.0001) for Day-5 Long and Day-6 Short (>91%) compared to the Day-5 Short group (<60%). A similar trend was observed for cases with and without a previous PGT-A. Regarding blastocyst expansion grade, informativity rates were lower in Day-5 Short, compared to Day-5 Long and Day-6 Short, regardless of expansion degree. This decrease was significant for Gardner grade expansion grade 3 (p=0.0005), 4 (p=0.0366) and 5-6 (p=0.0002). In addition, for a similar time in culture, the grade of expansion did not have an impact on the informativity rates. For concordance rates, no significant differences were observed among the three groups. In all cases concordance rates were 90.5% for Day-5 Short, 93.6% for Day-5 Long and 92.3% for Day-6 Short. No impact of the expansion grade was observed on concordance rates. CONCLUSION: niPGT-A in frozen-thawed blastocysts yields very high concordance rates with whole blastocysts, possibly limiting the need for invasive PGT-A and making it available for a wider range of patients.

Effect of time post warming to embryo transfer on human blastocyst metabolism and pregnancy outcome.

PURPOSE: This study is aiming to test whether variation in post warming culture time impacts blastocyst metabolism or pregnancy outcome. METHODS: In this single center retrospective cohort study, outcomes of 11,520 single frozen embryo transfer (FET) cycles were analyzed from January 2015 to December 2020. Patient treatments included both natural and programmed cycles. Time categories were determined using the time between blastocyst warming and embryo transfer: 0 (0- <1h), 1 (1-<2h), 2 (2-<3h), 3(3-<4h), 4 (4-<5), 5 (5-<6), 6 (6-<7) and 7 (7-8h). Non-invasive metabolic imaging of discarded human blastocysts for up to 10h was also performed using Fluorescence lifetime imaging microscopy (FLIM) to examine for metabolic perturbations during culture. RESULTS: The mean age of patients across all time categories were comparable (35.6 ± 3.9). Live birth rates (38-52%) and miscarriage rate (5-11%) were not statistically different across post-warming culture time. When assessing pregnancy outcomes based on the use of PGT-A, miscarriage and live birth rates were not statistically different across culture hours in both PGT-A and non-PGT cycles. Further metabolic analysis of blastocysts for the duration of 10h of culture post warming, revealed minimal metabolic changes of embryos in culture. CONCLUSION: Overall, our results show that differences in the time of post warming culture have no significant impact on miscarriage or live birth rate for frozen embryo transfers. This information can be beneficial for clinical practices with either minimal staffing or a high number of patient cases.

Metabolic imaging of human embryos is predictive of ploidy status but is not associated with clinical pregnancy outcomes: a pilot trial.

STUDY QUESTION: Does fluorescence lifetime imaging microscopy (FLIM)-based metabolic imaging assessment of human blastocysts prior to frozen transfer correlate with pregnancy outcomes? SUMMARY ANSWER: FLIM failed to distinguish consistent patterns in mitochondrial metabolism between blastocysts leading to pregnancy compared to those that did not. WHAT IS KNOWN ALREADY: FLIM measurements provide quantitative information on NAD(P)H and flavin adenine dinucleotide (FAD+) concentrations. The metabolism of embryos has long been linked to their viability, suggesting the potential utility of metabolic measurements to aid in selection. STUDY DESIGN, SIZE, DURATION: This was a pilot trial enrolling 121 IVF couples who consented to have their frozen blastocyst measured using non-invasive metabolic imaging. After being warmed, 105 couples' good-quality blastocysts underwent a 6-min scan in a controlled temperature and gas environment. FLIM-assessed blastocysts were then transferred without any intervention in management. PARTICIPANTS/MATERIALS, SETTING, METHODS: Eight metabolic parameters were obtained from each blastocyst (4 for NAD(P)H and 4 for FAD): short and long fluorescence lifetime, fluorescence intensity, and fraction of the molecule engaged with enzyme. The redox ratio (intensity of NAD(P)H)/(intensity of FAD) was also calculated. FLIM data were combined with known metadata and analyzed to quantify the ability of metabolic imaging to differentiate embryos that resulted in pregnancy from embryos that did not. De-identified discarded aneuploid human embryos (n = 158) were also measured to quantify correlations with ploidy status and other factors. Statistical comparisons were performed using logistic regression and receiver operating characteristic (ROC) curves with 5-fold cross-validation averaged over 100 repeats with random sampling. AUC values were used to quantify the ability to distinguish between classes. MAIN RESULTS AND THE ROLE OF CHANCE: No metabolic imaging parameters showed significant differences between good-quality blastocysts resulting in pregnancy versus those that did not. A logistic regression using metabolic data and metadata produced an ROC AUC of 0.58. In contrast, robust AUCs were obtained when classifying other factors such as comparison of Day 5 (n = 64) versus Day 6 (n = 41) blastocysts (AUC = 0.78), inner cell mass versus trophectoderm (n = 105: AUC = 0.88) and aneuploid (n = 158) versus euploid and positive pregnancy embryos (n = 108) (AUC = 0.82). LIMITATIONS, REASONS FOR CAUTION: The study protocol did not select which embryo to transfer and the cohort of 105 included blastocysts were all high quality. The study was also limited in number of participants and study sites. Increased power and performing the trial in more sites may have provided a stronger conclusion regarding the merits of the use of FLIM clinically. WIDER IMPLICATIONS OF THE FINDINGS: FLIM failed to distinguish consistent patterns in mitochondrial metabolism between good-quality blastocysts leading to pregnancy compared to those that did not. Blastocyst ploidy status was, however, highly distinguishable. In addition, embryo regions and embryo day were consistently revealed by FLIM. While metabolic imaging detects mitochondrial metabolic features in human blastocysts, this pilot trial indicates it does not have the potential to serve as an effective embryo viability detection tool. This may be because mitochondrial metabolism plays an alternative role post-implantation. STUDY FUNDING/COMPETING INTEREST(S): This study was sponsored by Optiva Fertility, Inc. Boston IVF contributed to the clinical site and services. Becker Hickl, GmbH, provided the FLIM system on loan. T.S. was the founder and held stock in Optiva Fertility, Inc., and D.S. and E.S. had options with Optiva Fertility, Inc., during this study. TRIAL REGISTRATION NUMBER: The study was approved by WCG Connexus IRB (Study Number 1298156).

Utilization of Cryopreserved Oocytes in Patients With Poor Ovarian Response After Planned Oocyte Cryopreservation.

Importance: Poor ovarian response (POR) to stimulation may impact patients' desire or need to utilize cryopreserved oocytes for family building in the future. These findings, captured by Society for Assisted Reproductive Technology (SART) national data, underscore the need for tailored counseling and further research into the decision-making processes influencing oocyte utilization. Objective: To examine the association of ovarian response to stimulation and the number of vitrified oocytes with the likelihood and timing of patients returning for oocyte utilization following planned oocyte cryopreservation (OC). Design, Setting, and Participants: This cohort study used data in the SART Clinical Outcome Reporting System for patients in US fertility clinics and data was used for eligible patients who underwent planned OC from January 2014 through December 2020. Data were analyzed from November 2022 to June 2023. Main outcomes and measures: The association between number of oocytes cryopreserved on return rate to utilize cryopreserved oocytes and the time from vitrification to warming. Results: A total of 67 893 autologous oocyte freezing cycles were performed in the US between 2014 and 2020, among 47 363 patients (mean [SD] age, 34.5 [4.7] years). Of these, 6421 (13.5%) were classified as patients with POR, with fewer than 5 oocytes vitrified across all ovarian stimulation cycles. A total of 1203 patients (2.5%) returned for oocyte warming and utilization. The rate of return was significantly higher in the POR group, with 260 (4.0%) returning compared with 943 (2.3%) in the normal responder group (P < .001). This trend was most notable in the age 30 to 34 years (warm cycle, 46 of 275 [16.7%] vs no warm cycle, 982 of 11 743 [8.4%]; P < .001) and age 35 to 39 years groups (warm cycle, 124 of 587 [21.1%] vs no warm cycle, 3433 of 23 012 [14.9%]; P < .001). The time elapsed from vitrification to warming was comparable between patients with POR (mean [SD], 716.1 [156.1] days) and normal responders (803.8 [160.7] days). A multivariate analysis adjusted for age, clinic region in the US, body mass index, and history of endometriosis was conducted to identify factors associated with the utilization of oocytes. The analysis revealed that having fewer than 5 oocytes vitrified was associated with higher odds of utilizing oocytes (OR, 1.52; 95% CI, 1.32-1.76). Conclusions and Relevance: This cohort study reveals a distinct pattern in the utilization of cryopreserved oocytes among patients undergoing planned OC in the US. Despite the increase in number of patients pursuing OC, there is a notably low rate of return to utilize previously vitrified oocytes; notably, patients with POR are more likely to return, although the time to return is similar to those with normal ovarian response.

Intra-patient analysis of individual weight gain or loss between IVF cycles: cycle now and transfer later.

STUDY QUESTION: What is the impact of clinically significant weight change on outcomes related to IVF cycle performance? SUMMARY ANSWER: While individual weight loss did not significantly impact ovarian response to stimulation or other cycle outcome parameters in our study, some positive associations were found for individual weight gain. WHAT IS KNOWN ALREADY: The role of weight-change in patients undergoing IVF has been largely studied by comparing weight loss in different cohorts of patients stratified by a static BMI. Specifically, obesity has been extensively studied in relation to its negative effects on assisted or unassisted conception outcomes and ovulatory function. Previous research has shown conflicting results, while BMI, which is commonly used as a marker of obesity, may not accurately reflect the underlying factors affecting fertility in obese patients. STUDY DESIGN, SIZE, DURATION: This study utilized a retrospective within-patient repeated measurement analysis design to assess the impact of weight change on IVF outcomes in cycles where all embryos were cryopreserved at the blastocyst stage for transfer at a later date. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was conducted at an academically affiliated fertility center. The data included 961 women who underwent at least two IVF cycles between December 2014 and June 2020, with documented short-term weight gain (n = 607) or weight loss (n = 354) within 1 year from their initial IVF cycle. Multivariable generalized estimating equations (GEE) and generalized linear mixed models (GLMM) were employed to assess associations between weight change and outcomes across cycles. MAIN RESULTS AND THE ROLE OF CHANCE: The multivariable models indicated that weight loss did not show any significant associations with the numbers of oocytes retrieved, or mature oocytes, the fertilization rate or the blastulation rate. However, weight gain demonstrated a minor positive association with the number of oocytes retrieved in both GEE models (coefficient: 0.01, 95% CI: 0.00-0.01) and GLMM models (0.01, 95% CI: 0.01-0.00). There was also a potential increase in the fertilization rate with weight gain, as indicated by a positive coefficient in both GEE models (coefficient: 0.01, 95% CI: 0.00-0.02) and GLMM models (coefficient: 0.01, 95% CI: 0.00-0.01). However, the association between weight gain and the embryo blastulation rate was not statistically significant in any model. LIMITATIONS, REASONS FOR CAUTION: This study focused on cycle performance parameters instead of reproductive outcomes, which restricted our ability to evaluate the impact of weight change on cumulative live birth rates. Additionally, the study did not account for variables such as stimulation protocols, potentially introducing confounding factors and limiting the generalizability of the results. WIDER IMPLICATIONS OF THE FINDINGS: Although obesity is associated with adverse obstetrical risks, there is less evidence of adverse reproductive outcomes in IVF cycles. We therefore recommend that an IVF cycle should not be delayed due to weight, so that the patient is not adversely affected by increasing age. The IVF cycle should aim to freeze all embryos, so that embryo transfer can then occur after weight loss, so as to limit the recognized obstetrical risks. STUDY FUNDING/COMPETING INTEREST(S): The study was not funded and there were no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Implicit bias in diagnosing mosaicism amongst preimplantation genetic testing providers: results from a multicenter study of 36 395 blastocysts.

STUDY QUESTION: Does the diagnosis of mosaicism affect ploidy rates across different providers offering preimplantation genetic testing for aneuploidies (PGT-A)? SUMMARY ANSWER: Our analysis of 36 395 blastocyst biopsies across eight genetic testing laboratories revealed that euploidy rates were significantly higher in providers reporting low rates of mosaicism. WHAT IS KNOWN ALREADY: Diagnoses consistent with chromosomal mosaicism have emerged as a third category of possible embryo ploidy outcomes following PGT-A. However, in the era of mosaicism, embryo selection has become increasingly complex. Biological, technical, analytical, and clinical complexities in interpreting such results have led to substantial variability in mosaicism rates across PGT-A providers and clinics. Critically, it remains unknown whether these differences impact the number of euploid embryos available for transfer. Ultimately, this may significantly affect clinical outcomes, with important implications for PGT-A patients. STUDY DESIGN, SIZE, DURATION: In this international, multicenter cohort study, we reviewed 36 395 consecutive PGT-A results, obtained from 10 035 patients across 11 867 treatment cycles, conducted between October 2015 and October 2021. A total of 17 IVF centers, across eight PGT-A providers, five countries and three continents participated in the study. All blastocysts were tested using trophectoderm biopsy and next-generation sequencing. Both autologous and donation cycles were assessed. Cycles using preimplantation genetic testing for structural rearrangements were excluded from the analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: The PGT-A providers were randomly categorized (A to H). Providers B, C, D, E, F, G, and H all reported mosaicism, whereas Provider A reported embryos as either euploid or aneuploid. Ploidy rates were analyzed using multilevel mixed linear regression. Analyses were adjusted for maternal age, paternal age, oocyte source, number of embryos biopsied, day of biopsy, and PGT-A provider, as appropriate. We compared associations between genetic testing providers and PGT-A outcomes, including the number of chromosomally normal (euploid) embryos determined to be suitable for transfer. MAIN RESULTS AND THE ROLE OF CHANCE: The mean maternal age (±SD) across all providers was 36.2 (±5.2). Our findings reveal a strong association between PGT-A provider and the diagnosis of euploidy and mosaicism. Amongst the seven providers that reported mosaicism, the rates varied from 3.1% to 25.0%. After adjusting for confounders, we observed a significant difference in the likelihood of diagnosing mosaicism across providers (P < 0.001), ranging from 6.5% (95% CI: 5.2-7.4%) for Provider B to 35.6% (95% CI: 32.6-38.7%) for Provider E. Notably, adjusted euploidy rates were highest for providers that reported the lowest rates of mosaicism (Provider B: euploidy, 55.7% (95% CI: 54.1-57.4%), mosaicism, 6.5% (95% CI: 5.2-7.4%); Provider H: euploidy, 44.5% (95% CI: 43.6-45.4%), mosaicism, 9.9% (95% CI: 9.2-10.6%)); and Provider D: euploidy, 43.8% (95% CI: 39.2-48.4%), mosaicism, 11.0% (95% CI: 7.5-14.5%)). Moreover, the overall chance of having at least one euploid blastocyst available for transfer was significantly higher when mosaicism was not reported, when we compared Provider A to all other providers (OR = 1.30, 95% CI: 1.13-1.50). Differences in diagnosing and interpreting mosaic results across PGT-A laboratories raise further concerns regarding the accuracy and relevance of mosaicism predictions. While we confirmed equivalent clinical outcomes following the transfer of mosaic and euploid blastocysts, we found that a significant proportion of mosaic embryos are not used for IVF treatment. LIMITATIONS, REASONS FOR CAUTION: Due to the retrospective nature of the study, associations can be ascertained, however, causality cannot be established. Certain parameters such as blastocyst grade were not available in the dataset. Furthermore, certain platform-related and clinic-specific factors may not be readily quantifiable or explicitly captured in our dataset. As such, a full elucidation of all potential confounders accounting for variability may not be possible. WIDER IMPLICATIONS OF THE FINDINGS: Our findings highlight the strong need for standardization and quality assurance in the industry. The decision not to transfer mosaic embryos may ultimately reduce the chance of success of a PGT-A cycle by limiting the pool of available embryos. Until we can be certain that mosaic diagnoses accurately reflect biological variability, reporting mosaicism warrants utmost caution. A prudent approach is imperative, as it may determine the difference between success or failure for some patients. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Torres Quevedo Grant, awarded to M.P. (PTQ2019-010494) by the Spanish State Research Agency, Ministry of Science and Innovation, Spain. M.P., L.B., A.R.L., A.L.R.d.C.L., N.P.P., M.P., D.S., F.A., A.P., B.M., L.D., F.V.M., D.S., M.R., E.P.d.l.B., A.R., and R.V. have no competing interests to declare. B.L., R.M., and J.A.O. are full time employees of IB Biotech, the genetics company of the Instituto Bernabeu group, which performs preimplantation genetic testing. M.G. is a full time employee of Novagen, the genetics company of Cegyr, which performs preimplantation genetic testing. TRIAL REGISTRATION NUMBER: N/A.

Food, nutrition, and fertility: from soil to fork.

Food and nutrition-related factors, including foods and nutrients consumed, dietary patterns, use of dietary supplements, adiposity, and exposure to food-related environmental contaminants, have the potential to impact semen quality and male and female fertility; obstetric, fetal, and birth outcomes; and the health of future generations, but gaps in evidence remain. On 9 November 2022, Tufts University's Friedman School of Nutrition Science and Policy and the school's Food and Nutrition Innovation Institute hosted a 1-d meeting to explore the evidence and evidence gaps regarding the relationships between food, nutrition, and fertility. Topics addressed included male fertility, female fertility and gestation, and intergenerational effects. This meeting report summarizes the presentations and deliberations from the meeting. Regarding male fertility, a positive association exists with a healthy dietary pattern, with high-quality evidence for semen quality and lower quality evidence for clinical outcomes. Folic acid and zinc supplementation have been found to not impact male fertility. In females, body weight status and other nutrition-related factors are linked to nearly half of all ovulation disorders, a leading cause of female infertility. Females with obesity have worse fertility treatment, pregnancy-related, and birth outcomes. Environmental contaminants found in food, water, or its packaging, including lead, perfluorinated alkyl substances, phthalates, and phenols, adversely impact female reproductive outcomes. Epigenetic research has found that maternal and paternal dietary-related factors can impact outcomes for future generations. Priority evidence gaps identified by meeting participants relate to the effects of nutrition and dietary patterns on fertility, gaps in communication regarding fertility optimization through changes in nutritional and environmental exposures, and interventions impacting germ cell mechanisms through dietary effects. Participants developed research proposals to address the priority evidence gaps. The workshop findings serve as a foundation for future prioritization of scientific research to address evidence gaps related to food, nutrition, and fertility.

Perinatal outcomes in 6640 singleton pregnancies after donor oocyte IVF across three continents over 7 years.

PURPOSE: Are trends in singleton donor oocyte IVF perinatal outcomes consistent over time among four international ethnically diverse infertility centers? METHODS: This retrospective cohort consisted of an infertility network of four international IVF centers across three continents. Singleton live births resulting from fresh and frozen donor oocyte embryo transfers from January 1, 2012 to December 31, 2018 were included. The main outcome measures were birth weight (BW), preterm birth (PTB), large for gestational age (LGA), small for gestational age (SGA) and gestational age (GA) at delivery. RESULTS: The entire cohort (n = 6640) consisted of 4753 fresh and 1887 frozen donor oocyte embryo transfers. Maternal age, parity, body mass index, neonatal sex and GA at delivery were similar for fresh and frozen donor oocyte embryo transfers in the entire cohort and within each infertility center. All four centers had a trend of decreased BW and rates of PTB before 32 weeks annually, although significance was not reached. Three of the four centers had annual increased trends of PTB before 37 weeks and LGA newborns, although significance was not reached. BWs for the entire cohort for fresh and frozen donor embryo transfers were 3166 g ± 601 g and 3137 g ± 626 g, respectively. CONCLUSION: Similar trends in perinatal outcomes were present across four international infertility centers over 7 years. The overall perinatal trends in donor oocyte IVF may be applicable to centers worldwide, but further studies in more geographic regions are needed.

Perinatal outcomes in 13,626 singleton pregnancies after autologous IVF across three continents over 7 years.

PURPOSE: Are trends in singleton autologous IVF perinatal outcomes consistent over time among five international infertility centers? METHODS: This was a retrospective cohort study from January 1, 2012, to December 31, 2018. This study was performed through a large infertility network at five international infertility centers in which patients who had a singleton live birth resulting from fresh and frozen autologous IVF cycles were included. The primary outcome was live birth weight (BW) with secondary outcomes of preterm birth (PTB), large for gestational age (LGA), small for gestational age (SGA), and gestational age at delivery. RESULTS: The entire cohort (n = 13,626) consisted of 6941 fresh and 6685 frozen autologous IVF cycles leading to singleton deliveries. Maternal age, parity, body mass index, neonatal sex, and GA at delivery were similar for fresh and frozen IVF cycles in the entire cohort and within each infertility center. Four centers had a trend of decreased BW and three centers had decreased rates of PTB before 32 and 28 weeks and LGA newborns annually, although significance was not reached. Three IVF centers had annual increased trends of PTB before 37 weeks and four centers had increased rates of SGA newborns, although significance was not reached. CONCLUSION: Similar trends in perinatal outcomes were present across five international infertility centers over 7 years. Additional studies are crucial to further assess and optimize perinatal outcomes at an international level.

From oocytes to a live birth: Are we improving the biological efficiency?

OBJECTIVE(S): The objectives of our study were to investigate the live birth rate (LBR) per oocyte retrieved during in vitro fertilization, in patients who had used all their embryos and to extrapolate the LBR in patients with remaining frozen embryos by calculating the expected LBR from these embryos. DESIGN: A retrospective cohort study. SETTING: A single academically affiliated fertility clinic. PATIENT(S): Autologous in vitro fertilization cycles from January 2014 to December 2020. Data on the number of oocytes retrieved, number of embryos obtained and transferred (at cleavage or blastocyst-stage), use of preimplantation genetic testing for aneuploidy (PGT-A), and number of live births were obtained. The expected LBR was estimated in patients with remaining frozen embryos according to nationally reported Society for Assisted Reproductive Technology LBR data. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Live birth rate per oocyte retrieved. RESULT(S): A total of 12,717 patients met the inclusion criteria and underwent a total of 20,677 oocyte retrievals which yielded a total of 248,004 oocytes and 57,268 embryos (fresh and frozen). In patients who had fully utilized all their embryos the LBR per oocyte was 2.82% (ranging from 11.3% aged <35 years to 1.2% aged >42 years). Stratification of the population based on PGT-A utilization yielded similar results (with PGT-A: 2.88% and without PGT-A: 2.79%). When stratified by the Society for Assisted Reproductive Technology age groups, the addition of PGT-A in patients aged 35-37 and 38-40 years yielded higher LBR per oocyte compared with patients who did not add PGT-A (P<.05). In patients with remaining frozen embryos who had added PGT-A, the projected LBR per oocyte was 8.34%. Use of PGT-A in patients aged <35 and 35-37 years decreased LBR per oocyte (P<.001 and P=.03, respectively) but improved LBR per oocyte in patients aged 38-40 and 41-42 years (P=.006 and P=.005, respectively). Poisson regression analysis demonstrated an age threshold of 38.5, below which PGT-A lowers LBR per oocyte compared with no PGT-A. CONCLUSION(S): Despite clinical and scientific advances in Assisted Reproductive Technology, with the current protocols of ovarian stimulation, the LBR per oocyte remains low reflecting a biological barrier that has yet to be overcome. Overall, the addition of PGT-A did not demonstrate improved outcomes.

Human embryo live imaging reveals nuclear DNA shedding during blastocyst expansion and biopsy.

Proper preimplantation development is essential to assemble a blastocyst capable of implantation. Live imaging has uncovered major events driving early development in mouse embryos; yet, studies in humans have been limited by restrictions on genetic manipulation and lack of imaging approaches. We have overcome this barrier by combining fluorescent dyes with live imaging to reveal the dynamics of chromosome segregation, compaction, polarization, blastocyst formation, and hatching in the human embryo. We also show that blastocyst expansion mechanically constrains trophectoderm cells, causing nuclear budding and DNA shedding into the cytoplasm. Furthermore, cells with lower perinuclear keratin levels are more prone to undergo DNA loss. Moreover, applying trophectoderm biopsy, a mechanical procedure performed clinically for genetic testing, increases DNA shedding. Thus, our work reveals distinct processes underlying human development compared with mouse and suggests that aneuploidies in human embryos may not only originate from chromosome segregation errors during mitosis but also from nuclear DNA shedding.

Acceptance of genetic editing and of whole genome sequencing of human embryos by patients with infertility before and after the onset of the COVID-19 pandemic.

RESEARCH QUESTION: Has acceptance of heritable genome editing (HGE) and whole genome sequencing for preimplantation genetic testing (PGT-WGS) of human embryos changed after the onset of COVID-19 among infertility patients? DESIGN: A written survey conducted between April and June 2018 and July and December 2021 among patients at a university-affiliated infertility practice. The questionnaire ascertained the acceptance of HGE for specific therapeutic or genetic 'enhancement' indications and of PGT-WGS to prevent adult disease. RESULTS: In 2021 and 2018, 172 patients and 469 patients (response rates: 90% and 91%, respectively) completed the questionnaire. In 2021, significantly more participants reported a positive attitude towards HGE, for therapeutic and enhancement indications. In 2021 compared with 2018, respondents were more likely to use HGE to have healthy children with their own gametes (85% versus 77%), to reduce disease risk for adult-onset polygenic disorders (78% versus 67%), to increase life expectancy (55% versus 40%), intelligence (34% versus 26%) and creativity (33% versus 24%). Fifteen per cent of the 2021 group reported a more positive attitude towards HGE because of COVID-19 and less than 1% a more negative attitude. In contrast, support for PGT-WGS was similar in 2021 and 2018. CONCLUSIONS: A significantly increased acceptance of HGE was observed, but not of PGT-WGS, after the onset of COVID-19. Although the pandemic may have contributed to this change, the exact reasons remain unknown and warrant further investigation. Whether increased acceptability of HGE may indicate an increase in acceptability of emerging biomedical technologies in general needs further investigation.

The nuclear lamina couples mechanical forces to cell fate in the preimplantation embryo via actin organization.

During preimplantation development, contractile forces generated at the apical cortex segregate cells into inner and outer positions of the embryo, establishing the inner cell mass (ICM) and trophectoderm. To which extent these forces influence ICM-trophectoderm fate remains unresolved. Here, we found that the nuclear lamina is coupled to the cortex via an F-actin meshwork in mouse and human embryos. Actomyosin contractility increases during development, upregulating Lamin-A levels, but upon internalization cells lose their apical cortex and downregulate Lamin-A. Low Lamin-A shifts the localization of actin nucleators from nucleus to cytoplasm increasing cytoplasmic F-actin abundance. This results in stabilization of Amot, Yap phosphorylation and acquisition of ICM over trophectoderm fate. By contrast, in outer cells, Lamin-A levels increase with contractility. This prevents Yap phosphorylation enabling Cdx2 to specify the trophectoderm. Thus, forces transmitted to the nuclear lamina control actin organization to differentially regulate the factors specifying lineage identity.

ART outcomes in lean compared to obese phenotypes of polycystic ovarian syndrome.

RESEARCH QUESTION: To investigate differences in reproductive outcomes among IVF patients with lean compared to obese polycystic ovarian syndrome (PCOS) phenotypes. DESIGN: A retrospective cohort study of patients with PCOS who underwent IVF in a single, academically affiliated infertility center in the USA between December 2014 and July 2020. The diagnosis of PCOS was assigned based on Rotterdam criteria. Patients were designated as lean (< 25) or overweight/obese (≥ 25) PCOS phenotype based on BMI (kg/m2) at cycle start. Baseline clinical and endocrinologic laboratory panel, cycle characteristics, and reproductive outcomes were analyzed. The cumulative live birth rate included up to 6 consecutives cycles. A Cox proportional hazards model and Kaplan-Meier curve for estimating live birth rates were used to compare the two phenotypes. RESULTS: A total of 1395 patients who underwent 2348 IVF cycles were included. The mean (SD) BMI was 22.7 (2.4) in the lean and 33.8 (6.0) in the obese group (p < 0.001). A number of endocrinological parameters were similar between lean and obese phenotypes: total testosterone 30.8 ng/dl (19.5) vs 34.1 (21.9), p > 0.02 and pre-cycle hemoglobin A1C 5.33% (0.38) vs 5.51% (0.51) p > 0.001, respectively. The CLBR was higher in those with a lean PCOS phenotype: 61.7% (373/604) vs 54.0% (764/1414) respectively. Miscarriage rates were significantly higher for O-PCOS patients (19.7% (214/1084) vs 14.5% (82/563) p < 0.001) and the rate of aneuploids was similar (43.5%, 43.8%, p = 0.8). A Kaplan-Meier curve estimating the proportion of patients with a live birth was higher in the lean group (log-rank test p = 0.013). After adjusting for potential confounders, the lean phenotype was associated with an increased hazard ratio for live birth: HR = 1.38 p < 0.001. CONCLUSIONS: Lean PCOS phenotype is associated with a significantly higher CLBR compared to their obese counterparts. Miscarriage rates were significantly higher among obese patients, despite comparable pre-cycle HBA1C and similar aneuploidy rates in patients who underwent PGT-A.

Day after rescue ICSI: eliminating total fertilization failure after conventional IVF with high live birth rates following cryopreserved blastocyst transfer.

STUDY QUESTION: What is the impact of day after rescue ICSI (r-ICSI) on success of fresh and frozen embryo transfers? SUMMARY ANSWER: The use of r-ICSI can virtually allay fears of total fertilization failure (TFF) after conventional IVF (C-IVF) and achieve high live birth rates after frozen blastocyst transfer. WHAT IS KNOWN ALREADY: More infertility clinics have resorted to the use of ICSI in place of C-IVF in IVF treatment owing to fear of TFF or a low fertilization rate. r-ICSI has been attempted either on the day of IVF or the day after. Day after r-ICSI has proved unsuccessful in the past. STUDY DESIGN, SIZE, DURATION: A retrospective data analysis was performed of 16 608 qualifying cases between April 2010 and July 2021 conducted at a single private academically affiliated fertility clinic. PARTICIPANTS/MATERIALS, SETTING, METHODS: r-ICSI was performed principally on patients with >4 metaphase II oocytes, showing no signs of fertilization 18 h after C-IVF. C-IVF was performed on patients who had >4 million total motile sperm after preparation. r-ICSI was then performed 18-24 h after insemination, using the sperm sample from the previous day. r-ICSI fertilization rates, cryopreservation of cleavage and blastocysts embryos, and pregnancy rates after fresh or frozen transfer were then assessed. MAIN RESULTS AND THE ROLE OF CHANCE: r-ICSI was performed on 377 patients (2.3% of eligible retrieval cycles) who had a mean (±SD) female and male age of 35.9 ± 4.5 and 38.1 ± 9.1 years, respectively. A total of 5459 oocytes were initially retrieved. Of the oocytes undergoing r-ICSI, 2389 (49.5%) fertilized normally, and 205 (54.4%) patients underwent a fresh embryo transfer. The live birth rates were 23/186 (12.3%) for fresh cleavage and 5/19 (26.3%) for fresh blastocyst stage transfers. In 145 cycles a blastocyst was frozen, and 137 transfers were performed with a 64/137 (46.7%) live birth rate. Of the 377 cycles receiving r-ICSI only, 25 of the qualifying cases failed to have any fertilization, reducing TFF to 25/16 608 (0.15%). LIMITATIONS, REASONS FOR CAUTION: This was a single-center retrospective study on a specific subset of patients, which may limit its generalizability to other clinics. WIDER IMPLICATIONS OF THE FINDINGS: r-ICSI allows a second opportunity to fertilize oocytes despite poor initial outcomes. Patients who had a frozen blastocyst transfer achieved high live birth rates, indicating that a resynchronization of the embryo with the endometrium can optimize r-ICSI cases. r-ICSI allays fears of TFF when using C-IVF, providing evidence that the overuse of ICSI in patients without male factor may not be warranted. STUDY FUNDING/COMPETING INTEREST(S): The study was internally funded by Boston IVF. The authors declare that they have no conflict of interest in relation to the data published in the article. TRIAL REGISTRATION NUMBER: N/A.

Noninvasive metabolic profiling of cumulus cells, oocytes, and embryos via fluorescence lifetime imaging microscopy: a mini-review.

A major challenge in ART is to select high-quality oocytes and embryos. The metabolism of oocytes and embryos has long been linked to their viability, suggesting the potential utility of metabolic measurements to aid in selection. Here, we review recent work on noninvasive metabolic imaging of cumulus cells, oocytes, and embryos. We focus our discussion on fluorescence lifetime imaging microscopy (FLIM) of the autofluorescent coenzymes NAD(P)H and flavine adenine dinucleotide (FAD+), which play central roles in many metabolic pathways. FLIM measurements provide quantitative information on NAD(P)H and FAD+ concentrations and engagement with enzymes, leading to a robust means of characterizing the metabolic state of cells. We argue that FLIM is a promising approach to aid in oocyte and embryo selection.

Compared with conventional insemination, intracytoplasmic sperm injection provides no benefit in cases of nonmale factor infertility as evidenced by comparable euploidy rate.

OBJECTIVE: To evaluate whether differences in euploidy rates exist between intracytoplasmic sperm injection (ICSI) and conventional insemination (CI) in nonmale factor infertility cases. DESIGN: Retrospective cohort study. SETTING: A single, academically affiliated infertility center in the United States. PATIENTS: A total of 3554 patients who underwent in vitro fertilization cycles from January 2014 to December 2021. All cycles that had preimplantation testing for aneuploidy (PGT-A) performed by trophectoderm biopsy and had a postpreparation sperm concentration >4 million total motile sperm per milliliter were included. MAIN OUTCOME MEASURES: The primary outcome was the embryo euploidy rate per embryo biopsied in the ICSI vs. CI group. Secondary outcomes included the fertilization rate and number of embryos biopsied. Generalized estimating equations with a Poisson distribution were used to estimate the euploid rate ratio (with total embryos biopsied as an offset), while accounting for multiple retrievals per patient. To adjust for confounding, a propensity score model was fit for ICSI using 14 baseline female and male characteristics. RESULTS: Oocytes retrieved and the number of embryos biopsied were similar in both groups, while the fertilization rate per oocyte retrieved was significantly lower with ICSI (0.64 vs. 0.66). The proportion of euploid embryos in the ICSI group was significantly lower when compared with CI (0.47 vs. 0.52), with a euploid rate ratio of 0.89. Interestingly, when accounting for the variation in PGT reference laboratories over the study time period, adjusting for the date of procedure did not change the relationship between ICSI and euploid rate (rate ratio = 0.89); however, after adjusting for the PGT reference laboratory, the relationship between ICSI and euploid rate was no longer significant (rate ratio = 0.97). CONCLUSIONS: In the setting of nonmale factor infertility, ICSI resulted in a lower fertilization rate and an 11% lower embryo euploid rate compared with CI. Although the data are not statistically significant when adjusted for the PGT reference laboratory, we still can conclude that ICSI does not provide any benefit. These data support the recommendation that CI should be the preferred methodology for fertilization in nonmale factor infertility cases.

Simulation-based training for embryo transfer for clinicians with differing levels of expertise: an application of the American Society for Reproductive Medicine Embryo Transfer Simulator.

Objective: To compare the learning curve of clinicians with different levels of embryo transfer (ET) experience using the American Society for Reproductive Medicine (ASRM) Embryo Transfer Simulator. Design: Prospective cohort study. Setting: Single large university-affiliated in vitro fertilization center. Patients: Participants with 3 levels of expertise with ET were recruited: "group 1" (Reproductive Endocrinology and Infertility attendings), "group 2" (Reproductive Endocrinology and Infertility nurses, advance practice providers, or medical assistants), and "group 3" (Obstetrics and Gynecology resident physicians). Interventions: All participants completed ET simulation training using uterine cases A, B, and C (easiest to most difficult) of the ASRM ET Simulator. Participants completed each case 5 times for a total of 15 repetitions. Main Outcome Measures: The primary outcome was ET simulation scores analyzed at each attempt for each uterine case, with a maximum score of 155. Secondary outcomes included self-assessed comfort levels before and after the completion of the simulation and total duration of ET. Comfort was assessed using a 5-point Likert scale. Results: Twenty-seven participants with 3 different levels of expertise with ET were recruited from December 2020 to February 2021. For cases A and B, median total scores were not significantly different between groups 1 and 3 at first or last attempts. Group 2 did not perform as well as group 3 at the beginning of case A or group 1 at the end of case B. All groups demonstrated a decrease in total time from the first attempt to the last attempt for both cases. For case C, the "difficult" uterus, groups 2 and 3 exhibited the greatest improvement in total median score: from 0 to 75 from the first to last attempt. Group 1 scored equally well from first through last attempts. Although no one from group 2 or 3 achieved a passing score with the first attempt (80% of the max score), approximately 30% had passing scores at the last attempt. Groups 1 and 3 showed a significant decrease in total time across attempts for case C. Following simulation, 100% of groups 2 and 3 reported perceived improvement in their skills. Group 3 showed significant improvement in comfort scores with Likert scores of 1.71 ± 0.76 and 1.0 ± 0.0 for the "Easy" and "Difficult" cases, respectively, before simulation and 4.57 ± 0.53 and 2.4 ± 1.1 after simulation. Conclusions: The ASRM ET Simulator was effective in improving both technical skill and comfort level, particularly for those with little to no ET experience and was most marked when training on a difficult clinical case.