Blastocyst expansion score and trophectoderm morphology strongly predict successful clinical pregnancy and live birth following elective single embryo blastocyst transfer (eSET): a national study

Comparison of the developmental competence of in vitro-produced mouse embryos cultured under 5 versus 2% O2 with in vivo-derived blastocysts

PURPOSE

The prevalence of infertility in Canada has substantially increased over 30 years, and plateaued success rates of culture systems warrant further optimization for transfer outcomes. In clinical programs, embryos commonly undergo extended culture under 5% O2 until the blastocyst stage. The aim of this study is to characterize the developmental competence and stress-related responses of embryos cultured under 5 versus 2% O2 in comparison to in vivo-derived blastocysts. We hypothesized 2% O2 compromises developmental competence through altered embryonic stress responses and induction of apoptosis-related genes relative to those cultured under 5% O2 and in vivo-derived blastocysts.

METHODS

Quantitative measures of development and relative expressions of a cohort of stress-related genes in CD1 mouse zygotes cultured to blastocysts under 5 or 2% O2 were compared to in vivo-derived embryos. Apoptotic responses were evaluated using an immunofluorescence assay for Caspase-3.

RESULTS

The mean percentage of blastocysts developed, and total cell number of embryos derived in vivo or cultured under 5% O2 was significantly higher than those cultured under 2% O2. Blastocyst expansion was greatest in embryos cultured under 5% O2. Stress response genes were significantly upregulated in embryos cultured under 2% O2, and expression of antioxidant-related genes was significantly lower in cultured versus in vivo-derived embryos. Caspase-3 immunofluorescence was significantly higher in cultured embryos versus in vivo-derived embryos.

CONCLUSION

We inferred that 5% O2 systems better approximate physiologic oxygen availability for culture of mouse embryos, warranting re-evaluation of culturing embryos under threshold or sub-physiologic oxygen concentrations during clinical IVF programs.

Trophectoderm grade as a predictor of beta human-chorionic gonadotropin rise in early pregnancy

PURPOSE

To evaluate the association, if any, between the grade of the trophectoderm (TE) and the rate at which β-human-chorionic gonadotropin (β-HCG) rises in early pregnancy.

METHODS

This is a retrospective cohort study including 1116 singleton clinical pregnancies resulting from in vitro fertilization with single day 5 blastocyst transfer at an academic fertility center. TE quality was assessed by trained embryologists employing standard criteria. Three groups were formed based on the TE grade: grade A (n = 358), grade B (n = 628), and grade C (n = 130). Main outcome measure was the rise (%) in serum levels of β-HCG (days 12 to 14 post embryo transfer), using the following formula [(β-HCG D14 - β-HCG D12) * 100/β-HCG D12].

RESULTS

Fresh embryo transfers accounted for 64.1% of the population. Overall, in adjusted models there were no significant differences in the β-HCG% rise when comparing the TE grade C group to TE grade A [adjβ (95%CI): 10.09 (- 0.05, 20.22)] or when comparing TE grade Β group to TE grade A [4.46 (- 2.97, 11.88)]. When the analysis was restricted to fresh embryo transfers, significant differences were observed in the % rise of β-HCG when comparing the TE grade C group to TE grade A [adjβ (95%CI): 21.71 (5.67, 37.74)], but not when comparing the TE grade B group to TE grade A [2.68 (- 5.59, 10.95)]. In frozen transfers, there were no significant differences.

CONCLUSION

TE grade appears to impact early pregnancy serum β-HCG levels in the setting of a fresh day 5 embryo transfer, even after adjusting for potential confounders.

Visual interpretability of image-based classification models by generative latent space disentanglement applied to in vitro fertilization

The success of deep learning in identifying complex patterns exceeding human intuition comes at the cost of interpretability. Non-linear entanglement of image features makes deep learning a "black box" lacking human meaningful explanations for the models' decision. We present DISCOVER, a generative model designed to discover the underlying visual properties driving image-based classification models. DISCOVER learns disentangled latent representations, where each latent feature encodes a unique classification-driving visual property. This design enables "human-in-the-loop" interpretation by generating disentangled exaggerated counterfactual explanations. We apply DISCOVER to interpret classification of in vitro fertilization embryo morphology quality. We quantitatively and systematically confirm the interpretation of known embryo properties, discover properties without previous explicit measurements, and quantitatively determine and empirically verify the classification decision of specific embryo instances. We show that DISCOVER provides human-interpretable understanding of "black box" classification models, proposes hypotheses to decipher underlying biomedical mechanisms, and provides transparency for the classification of individual predictions.

Platelet-rich plasma infusion as an adjunct treatment for persistent thin lining in frozen embryo transfer cycles: first US experience report

PURPOSE

To study effect of intrauterine infusion of platelet-rich plasma (PRP) on endometrial growth in the setting of thin endometrial lining in patients with prior cancelled or failed frozen embryo transfer (FET) cycles.

MATERIALS AND METHODS

Single-arm cohort study of forty-six patients (51 cycles) with endometrial lining thickness (EMT) < 6 mm in prior cancelled or failed FET cycles requesting intrauterine PRP treatment in upcoming FET cycle. The primary outcomes were final EMT in FET cycle and change in EMT after PRP. The secondary outcomes were overall pregnancy rate, clinical pregnancy rate, miscarriage rate, ongoing pregnancy, and live birth rates.

RESULTS

The mean pre-PRP EMT in all FET cycles was 4.0 ± 1.1 mm, and mean post-PRP EMT (final) was 7.1 ± 1.0 mm. Of 51 cycles, 33 (64.7%) reached ≥ 7 mm after PRP administration. There was a significant difference between pre-PRP EMT and post-PRP EMT in all FET cycles, with mean difference of 3.0 ± 1.5 mm. Three cycles were cancelled for failure to reach adequate lining. Total pregnancy rate was 72.9% in our cohort of 48 cycles that proceeded to transfer. Clinical pregnancy rate was 54.2% (26/48 FET cycles); clinical miscarriage rate was 14.3% (5/35 pregnancies). Twenty six women had live birth (18 with EMT ≥ 7 mm and 8 with EMT < 7 mm). Response to PRP was not correlated with any pre-cycle characteristics.

CONCLUSION

We demonstrate a significant improvement in lining thickness and pregnancy rates in this challenging cohort of women after PRP infusion, with no adverse events. Cost-effectiveness of PRP with benefits and alternatives should be carefully considered.

The Association between Embryo Development and Chromosomal Results from PGT-A in Women of Advanced Age: A Prospective Cohort Study

Embryo morphology and morphokinetics have been studied for their association with euploid embryos. However, the results are controversial, especially in the advanced-aged women group, when the risk of aneuploidy increases significantly. This prospective cohort study evaluated the association between embryo development between day-3 cleavage and day-5 blastocyst stages and euploidy rates, determined using preimplantation genetic testing for aneuploidy (PGT-A). Embryos from women aged 35 years and above who underwent intracytoplasmic sperm injections and PGT-A were studied. Day-3 cleavage-stage embryos were evaluated for their cell number, and day-5 blastocyst-stage embryos were evaluated for their morphological grade. Embryo development from day 3 to day 5 was categorized as either good or poor development and evaluated for its association with the PGT-A results. We evaluated 325 embryos from 101 infertile couples. It was found that 55.17% of blastocysts with good development and 29.83% with poor development were euploid. A significant association was found between embryo development and euploidy rates in advanced-aged women (p < 0.001). Also, there were significantly higher rates of euploid embryos with good blastocyst morphological grades, especially blastocyst expansion grades and trophectoderm grades. In conclusion, embryo morphokinetics shows promising results in predicting euploidy in advanced female age.

Influence of delayed blastulation and expansion grade on clinical outcomes of high-quality blastocyst transfer: an analysis of 1751 frozen-thawed cycles

The aim of the study was to compare retrospectively the extent of blastulation timing (Day 5 or later) and expansion grade to predict the ability of blastocysts to give rise to a pregnancy. Blastocysts frozen on day 5 with a lower expansion grade (group D5) or day 6 with a higher expansion grade (group D6) were included. A single embryo was thawed and transferred on day 5 after ovulation or progesterone supplementation. Differences in patient baseline characteristics, endometrial preparation and pregnancy outcomes between groups were stratified by patient age and anti-Müllerian hormone (AMH) levels. Logistic regression was used to analyse the results. A total of 617 blastocysts in group D5 and 1134 blastocysts in group D6 were assessed. Stratified analyses showed higher biochemical pregnancy, clinical pregnancy and live birth rates for patients aged less than 30 years old, and higher ongoing pregnancy rate for patients with AMH ≥ 1.1 ng/ml. For patients aged less than 30 years old, the biochemical pregnancy, clinical pregnancy and live birth rates in group D5 were higher than those in group D6.

Similar implantation competence in euploid blastocysts developed on day 5 or day 6 in young women: a retrospective cohort study

The results from different studies are inconsistent regarding whether development potential correlated with embryo development speed after single euploid blastocyst transfer. The age-associated reproductive decline is not only because of the difference in aneuploidy rates but also because of metabolic and epigenetic changes of the embryos. Therefore, we aimed to assess the independent effect of embryo development speed on implantation potential in young women. A total of 326 young women who underwent preimplantation genetic testing for monogenic diseases with aneuploidy screening were analyzed. Day-5 and day-6 euploid blastocysts yielded similar implantation rates (65.20 vs. 61.22%). The odds ratio (OR) remained non-significant after adjusting for confounders (adjusted OR = 0.84, 95% confidence interval 0.52-1.36). There was a trend that day-6 euploid blastocysts had a higher miscarriage rate (13.33 vs. 9.20%). However, the live birth delivery rate of day-5 blastocysts was similar to that of day-6 blastocysts (59.20 vs. 53.06%). In the stratified analysis, live birth delivery rates were similar between day-5 and day-6 similarly graded euploid blastocysts (excellent and good, 62.04 vs. 64.71%; average, 58.73 vs. 53.70%; poor, 43.75 vs. 44.44%). Embryo development speed has no obvious impact on implantation competence in young women's vitrified/warmed euploid embryo transfer cycles.

An artificial intelligence algorithm for automated blastocyst morphometric parameters demonstrates a positive association with implantation potential

Blastocyst selection is primarily based on morphological scoring systems and morphokinetic data. These methods involve subjective grading and time-consuming techniques. Artificial intelligence allows for objective and quick blastocyst selection. In this study, 608 blastocysts were selected for transfer using morphokinetics and Gardner criteria. Retrospectively, morphometric parameters of blastocyst size, inner cell mass (ICM) size, ICM-to-blastocyst size ratio, and ICM shape were automatically measured by a semantic segmentation neural network model. The model was trained on 1506 videos with 102 videos for validation with no overlap between the ICM and trophectoderm models. Univariable logistic analysis found blastocyst size and ICM-to-blastocyst size ratio to be significantly associated with implantation potential. Multivariable regression analysis, adjusted for woman age, found blastocyst size to be significantly associated with implantation potential. The odds of implantation increased by 1.74 for embryos with a blastocyst size greater than the mean (147 ± 19.1 μm). The performance of the algorithm was represented by an area under the curve of 0.70 (p < 0.01). In conclusion, this study supports the association of a large blastocyst size with higher implantation potential and suggests that automatically measured blastocyst morphometrics can be used as a precise, consistent, and time-saving tool for improving blastocyst selection.

Predicting the likelihood of live birth: an objective and user-friendly blastocyst grading system

RESEARCH QUESTION

Can day-5 blastocysts be ranked according to their likelihood of live birth using an objective and user-friendly grading system?

DESIGN

A retrospective multicentre study conducted between 2017 and 2019, including 1044 day-5 blastocysts. Blastocyst expansion degree, trophectoderm and inner cell mass quality were assessed morphologically and morphometrically. Several analyses were conducted: the association between the qualitative and quantitative assessment for the blastocyst expansion degree and the number of trophectoderm cells; the effect of the embryo quality on day 3 and the contribution of the three blastocyst parameters to live birth, with logistic regression; and a decision tree with the most significant variables to create the new scoring system.

RESULTS

Cut-off points were found to discriminate between expanding and expanded blastocysts (165 µm for blastocyst diameter) and between trophectoderm grades (A: ≥14 cells; B: 11-13 cells; C: ≤10 cells). When the embryos reached the blastocyst stage, their quality on day 3 did not add predictive value for implantation and live birth. In the logistic regression analysis, the only parameter capable of significantly predicting the live birth likelihood was the trophectoderm grade: A versus C (OR 1.95, 95% CI 1.26 to 3.0); B versus C (OR 1.71, 95% CI 1.22 to 2.4). The decision tree supported the finding that the trophectoderm grade had the highest predictive value for a live birth, followed by the blastocyst expansion degree in a second step.

CONCLUSIONS

This new method makes objective blastocyst assessment feasible, allowing for standardization and exportation to other laboratories worldwide.

The correlation between morphological parameters and the incidence of de novo chromosomal abnormalities in 3238 biopsied blastocysts

PURPOSE

The aim of this study was to determine the relationship between morphological parameters and the incidence of de novo chromosomal abnormalities.

METHODS

This was a retrospective cohort study of 652 patients who underwent 921 cycles with 3238 blastocysts biopsied. The embryo grades were evaluated according to Gardner and Schoolcraft's system. The incidence of euploidy, whole chromosomal aneuploidy (W-aneuploidy), segmental chromosomal aneuploidy (S-aneuploidy), and mosaicism in trophectoderm (TE) cell biopsies was analyzed.

RESULTS

The euploidy decreased significantly with maternal age and was positively correlated biopsy day and morphological parameters. The W-aneuploidy increased significantly with maternal age and was negatively correlated biopsy day and morphological parameters. Parental age, TE biopsy day, and morphological parameters were not associated with S-aneuploidy and mosaicism, except that TE grade C blastocysts had significantly higher mosaicism than TE grade A blastocysts. Subanalysis in different female age groups showed that euploidy and W-aneuploidy had a significant correlation with TE biopsy day among women aged ≤ 30 y and 31-35 y, with expansion degree among women aged ≥ 36 y, with ICM grade among women aged ≥ 31 y, and with TE grade among all female age ranges.

CONCLUSION

Female age, embryo developmental speed and blastocyst morphological parameters are associated with euploidy and whole chromosomal aneuploidy. The predictive value of these factors varies across female age groups. Parental age, embryo developmental speed, expansion degree, and ICM grade are not associated with the incidence of segmental aneuploidy or mosaicism, but TE grade seemingly has a weak correlation with segmental aneuploidy and mosaicism in embryos.

Towards Automation in IVF: Pre-Clinical Validation of a Deep Learning-Based Embryo Grading System during PGT-A Cycles

Preimplantation genetic testing for aneuploidies (PGT-A) is arguably the most effective embryo selection strategy. Nevertheless, it requires greater workload, costs, and expertise. Therefore, a quest towards user-friendly, non-invasive strategies is ongoing. Although insufficient to replace PGT-A, embryo morphological evaluation is significantly associated with embryonic competence, but scarcely reproducible. Recently, artificial intelligence-powered analyses have been proposed to objectify and automate image evaluations. iDAScore v1.0 is a deep-learning model based on a 3D convolutional neural network trained on time-lapse videos from implanted and non-implanted blastocysts. It is a decision support system for ranking blastocysts without manual input. This retrospective, pre-clinical, external validation included 3604 blastocysts and 808 euploid transfers from 1232 cycles. All blastocysts were retrospectively assessed through the iDAScore v1.0; therefore, it did not influence embryologists' decision-making process. iDAScore v1.0 was significantly associated with embryo morphology and competence, although AUCs for euploidy and live-birth prediction were 0.60 and 0.66, respectively, which is rather comparable to embryologists' performance. Nevertheless, iDAScore v1.0 is objective and reproducible, while embryologists' evaluations are not. In a retrospective simulation, iDAScore v1.0 would have ranked euploid blastocysts as top quality in 63% of cases with one or more euploid and aneuploid blastocysts, and it would have questioned embryologists' ranking in 48% of cases with two or more euploid blastocysts and one or more live birth. Therefore, iDAScore v1.0 may objectify embryologists' evaluations, but randomized controlled trials are required to assess its clinical value.

The impact of blastocyst freezing and biopsy on the association of blastocyst morphological parameters with live birth and singleton birthweight

OBJECTIVE

To explore whether the associations of 3 blastocyst morphological parameters, namely, degree of blastocyst expansion (expansion), appearance of trophectoderm (TE) and inner cell mass, with live birth and singleton birth weight are influenced by blastocyst freezing and biopsy.

DESIGN

A retrospective study.

SETTING

An assisted reproductive technology center.

PATIENT(S)

28,515 single blastocyst transfer cycles between January 2014 and August 2019.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Live birth and singleton birth weight.

RESULT(S)

Blastocyst transfer cycles were divided into 4 groups: biopsied blastocyst cycles (biopsied-blast), thawed blastocyst cycles (thawed-blast), blastocyst from thawed cleavage embryo cycles (blast-thawed-D3), and fresh blastocyst cycles (fresh-blast). Subgroup analyses by blastocyst stage (day 5 and day 6) were performed in thawed-blast and blast-thawed-D3. Because almost all blastocysts were biopsied on day 6 and fresh blastocysts were transferred on day 5, the biopsied-blast and fresh-blast were not divided into subgroups. First, the associations between blastocyst morphological parameters and live birth were analyzed. To explore the effect of freezing, we compared day-5 frozen cycles (thawed-blast) vs. day-5 fresh cycles (including fresh-blast and blast-thawed-D3) and day 6 frozen cycles (thawed-blast) vs. day-6 fresh cycles (blast-thawed-D3). Inner cell mass and TE were associated with live birth for day 5 embryos, and only TE affected live birth for day-6 embryos. The associations were the same in frozen cycles and fresh cycles. To explore the effect of biopsy, we compared day-6 biopsied cycles (biopsied-blast) vs. day-6 nonbiopsied cycles (including thawed-blast and blast-thawed-D3). All the 3 parameters were associated with live birth in biopsied-blast, whereas only TE was associated with live birth in nonbiopsied cycles. In addition, the associations between blastocyst morphological parameters and singleton birthweight were analyzed. In the 6 subgroups, expansion stage of day-6 embryos in biopsied-blast and TE grade of day-6 embryos in thawed-blast were associated with birth weight, and there are no associations in other subgroups.

CONCLUSION(S)

The association of blastocyst morphological parameters with live birth may be affected by blastocyst biopsy and/or genetic testing, and its association with birth weight may be affected by blastocyst freezing and biopsy and/or genetic testing.

Transcriptomic signatures in trophectoderm and inner cell mass of human blastocysts classified according to developmental potential, maternal age and morphology

Selection of high-quality embryos is important to achieve successful pregnancy in assisted reproductive technology (ART). Recently, it has been debated whether RNA-sequencing (RNA-Seq) should be applied to ART to predict embryo quality. However, information on genes that can serve as markers for pregnant expectancy is limited. Furthermore, there is no information on which transcriptome of trophectoderm (TE) or inner cell mass (ICM) is more highly correlated with pregnant expectancy. Here, we performed RNA-Seq analysis of TE and ICM of human blastocysts, the pregnancy expectation of which was retrospectively determined using the clinical outcomes of 1,890 cases of frozen-thawed blastocyst transfer. We identified genes that were correlated with the expected pregnancy rate in ICM and TE, respectively, with a larger number of genes identified in TE than in ICM. Downregulated genes in the TE of blastocysts that were estimated to have lower expectation of pregnancy included tight junction-related genes such as CXADR and ATP1B1, which have been implicated in peri-implantation development. Moreover, we identified dozens of differentially expressed genes by regrouping the blastocysts based on the maternal age and the Gardner score. Additionally, we showed that aneuploidy estimation using RNA-Seq datasets does not correlate with pregnancy expectation. Thus, our study provides an expanded list of candidate genes for the prediction of pregnancy in human blastocyst embryos.

Embryologist agreement when assessing blastocyst implantation probability: is data-driven prediction the solution to embryo assessment subjectivity?

STUDY QUESTION

What is the accuracy and agreement of embryologists when assessing the implantation probability of blastocysts using time-lapse imaging (TLI), and can it be improved with a data-driven algorithm?

SUMMARY ANSWER

The overall interobserver agreement of a large panel of embryologists was moderate and prediction accuracy was modest, while the purpose-built artificial intelligence model generally resulted in higher performance metrics.

WHAT IS KNOWN ALREADY

Previous studies have demonstrated significant interobserver variability amongst embryologists when assessing embryo quality. However, data concerning embryologists' ability to predict implantation probability using TLI is still lacking. Emerging technologies based on data-driven tools have shown great promise for improving embryo selection and predicting clinical outcomes.

STUDY DESIGN, SIZE, DURATION

TLI video files of 136 embryos with known implantation data were retrospectively collected from two clinical sites between 2018 and 2019 for the performance assessment of 36 embryologists and comparison with a deep neural network (DNN).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We recruited 39 embryologists from 13 different countries. All participants were blinded to clinical outcomes. A total of 136 TLI videos of embryos that reached the blastocyst stage were used for this experiment. Each embryo's likelihood of successfully implanting was assessed by 36 embryologists, providing implantation probability grades (IPGs) from 1 to 5, where 1 indicates a very low likelihood of implantation and 5 indicates a very high likelihood. Subsequently, three embryologists with over 5 years of experience provided Gardner scores. All 136 blastocysts were categorized into three quality groups based on their Gardner scores. Embryologist predictions were then converted into predictions of implantation (IPG ≥ 3) and no implantation (IPG ≤ 2). Embryologists' performance and agreement were assessed using Fleiss kappa coefficient. A 10-fold cross-validation DNN was developed to provide IPGs for TLI video files. The model's performance was compared to that of the embryologists.

MAIN RESULTS AND THE ROLE OF CHANCE

Logistic regression was employed for the following confounding variables: country of residence, academic level, embryo scoring system, log years of experience and experience using TLI. None were found to have a statistically significant impact on embryologist performance at α = 0.05. The average implantation prediction accuracy for the embryologists was 51.9% for all embryos (N = 136). The average accuracy of the embryologists when assessing top quality and poor quality embryos (according to the Gardner score categorizations) was 57.5% and 57.4%, respectively, and 44.6% for fair quality embryos. Overall interobserver agreement was moderate (κ = 0.56, N = 136). The best agreement was achieved in the poor + top quality group (κ = 0.65, N = 77), while the agreement in the fair quality group was lower (κ = 0.25, N = 59). The DNN showed an overall accuracy rate of 62.5%, with accuracies of 62.2%, 61% and 65.6% for the poor, fair and top quality groups, respectively. The AUC for the DNN was higher than that of the embryologists overall (0.70 DNN vs 0.61 embryologists) as well as in all of the Gardner groups (DNN vs embryologists-Poor: 0.69 vs 0.62; Fair: 0.67 vs 0.53; Top: 0.77 vs 0.54).

LIMITATIONS, REASONS FOR CAUTION

Blastocyst assessment was performed using video files acquired from time-lapse incubators, where each video contained data from a single focal plane. Clinical data regarding the underlying cause of infertility and endometrial thickness before the transfer was not available, yet may explain implantation failure and lower accuracy of IPGs. Implantation was defined as the presence of a gestational sac, whereas the detection of fetal heartbeat is a more robust marker of embryo viability. The raw data were anonymized to the extent that it was not possible to quantify the number of unique patients and cycles included in the study, potentially masking the effect of bias from a limited patient pool. Furthermore, the lack of demographic data makes it difficult to draw conclusions on how representative the dataset was of the wider population. Finally, embryologists were required to assess the implantation potential, not embryo quality. Although this is not the traditional approach to embryo evaluation, morphology/morphokinetics as a means of assessing embryo quality is believed to be strongly correlated with viability and, for some methods, implantation potential.

WIDER IMPLICATIONS OF THE FINDINGS

Embryo selection is a key element in IVF success and continues to be a challenge. Improving the predictive ability could assist in optimizing implantation success rates and other clinical outcomes and could minimize the financial and emotional burden on the patient. This study demonstrates moderate agreement rates between embryologists, likely due to the subjective nature of embryo assessment. In particular, we found that average embryologist accuracy and agreement were significantly lower for fair quality embryos when compared with that for top and poor quality embryos. Using data-driven algorithms as an assistive tool may help IVF professionals increase success rates and promote much needed standardization in the IVF clinic. Our results indicate a need for further research regarding technological advancement in this field.

STUDY FUNDING/COMPETING INTEREST(S)

Embryonics Ltd is an Israel-based company. Funding for the study was partially provided by the Israeli Innovation Authority, grant #74556.

TRIAL REGISTRATION NUMBER

N/A.

Klausen T, K. Danielsen A, Thomsen T, Bentin-Ley U, B. Knudsen U, Laursen S, R. Petersen M, Haahr K, Petersen K, Lemmen JG, Hindkjær J, Kirk J, Fedder J, J. Almind G, Hnida C, Troest B, B. Povlsen B, Zedeler A, Gabrielsen A, Larsen T, S. Kesmodel U. Is paternal age associated with transfer day, developmental stage, morphology, and initial hCG-rise of the competent blastocyst leading to live birth? A multicenter cohort study

In this study we investigated whether age of men undergoing assisted reproductive technology (ART) treatment was associated with day of transfer, stage, morphology, and initial hCG-rise of the competent blastocyst leading to a live birth? The design was a multicenter historical cohort study based on exposure (age) and outcome data (blastocyst stage and morphology and initial hCG-rise) from men whose partner underwent single blastocyst transfer resulting in singleton pregnancy/birth. The ART treatments were carried out at sixteen private and university-based public fertility clinics. We included 7246 men and women, who between 2014 and 2018 underwent controlled ovarian stimulation (COS) or Frozen-thawed Embryo Transfer (FET) with a single blastocyst transfer resulting in singleton pregnancy were identified. 4842 men with a partner giving birth were included, by linking data to the Danish Medical Birth Registry. We showed that the adjusted association between paternal age and transfer day in COS treatments was OR 1.06, 95% CI (1.00;1.13). Meaning that for every increase of one year, men had a 6% increased probability that the competent blastocyst was transferred on day 6 compared to day 5. Further we showed that the mean difference in hCG values when comparing paternal age group 30–34, 35–39 and 40–45 with the age group 25–29 in those receiving COS treatment, all showed significantly lower adjusted values for older men. In conclusion we hypothesize that the later transfer (day 6) in female partners of older men may be due to longer time spent by the oocyte to repair fragmented DNA of the sperm cells, which should be a focus of future research in men.

Correlation between an annotation-free embryo scoring system based on deep learning and live birth/neonatal outcomes after single vitrified-warmed blastocyst transfer: a single-centre, large-cohort retrospective study

Propose

Does an annotation-free embryo scoring system based on deep learning and time-lapse sequence images correlate with live birth (LB) and neonatal outcomes?

Methods

Patients who underwent SVBT cycles (3010 cycles, mean age: 39.3 ± 4.0). Scores were calculated using the iDAScore software module in the Vitrolife Technology Hub (Vitrolife, Gothenburg, Sweden). The correlation between iDAScore, LB rates, and total miscarriage (TM), including 1st- and 2nd-trimester miscarriage, was analysed using a trend test and multivariable logistic regression analysis. Furthermore, the correlation between the iDAScore and neonatal outcomes was analysed.

Results

LB rates decreased as iDAScore decreased (P < 0.05), and a similar inverse trend was observed for the TM rates. Additionally, multivariate logistic regression analysis showed that iDAScore significantly correlated with increased LB (adjusted odds ratio: 1.811, 95% CI: 1.666–1.976, P < 0.05) and decreased TM (adjusted odds ratio: 0.799, 95% CI: 0.706–0.905, P < 0.05). There was no significant correlation between iDAScore and neonatal outcomes, including congenital malformations, sex, gestational age, and birth weight. Multivariate logistic regression analysis, which included maternal and paternal age, maternal body mass index, parity, smoking, and presence or absence of caesarean section as confounding factors, revealed no significant difference in any neonatal characteristics.

Conclusion

Automatic embryo scoring using iDAScore correlates with decreased miscarriage and increased LB and has no correlation with neonatal outcomes.

Supplementary information

The online version contains supplementary material available at 10.1007/s10815-022-02562-5.

IGF2 reduces meiotic defects in oocytes from obese mice and improves embryonic developmental competency

BACKGROUND

Maternal obesity is a global issue that has devastating effects across the reproductive spectrum such as meiotic defects in oocytes, consequently worsening pregnancy outcomes. Different studies have shown that such types of meiotic defects originated from the oocytes of obese mothers. Thus, there is an urgent need to develop strategies to reduce the incidence of obesity-related oocyte defects that adversely affect pregnancy outcomes. Multiple growth factors have been identified as directly associated with female reproduction; however, the impact of various growth factors on female fertility in response to obesity remains poorly understood.

METHODS

The immature GV-stage oocytes from HFD female mice were collected and cultured in vitro in two different groups (HFD oocytes with and without 50 nM IGF2), however; the oocytes from ND mice were used as a positive control. HFD oocytes treated with or without IGF2 were further used to observe the meiotic structure using different analysis including, the spindle and chromosomal analysis, reactive oxygen species levels, mitochondrial functional activities, and early apoptotic index using immunofluorescence. Additionally, the embryonic developmental competency and embryos quality of IGF2-treated zygotes were also determined.

RESULTS

In our findings, we observed significantly reduced contents of insulin-like growth factor 2 (IGF2) in the serum and oocytes of obese mice. Our data indicated supplementation of IGF2 in a culture medium improves the blastocyst formation: from 46% in the HFD group to 61% in the HFD + IGF2-treatment group (50 nM IGF2). Moreover, adding IGF2 to the culture medium reduces the reactive oxygen species index and alleviates the frequency of spindle/chromosome defects. We found increased mitochondrial functional activity in oocytes from obese mice after treating the oocytes with IGF2: observed elevated level of adenosine triphosphate, increased mitochondrial distribution, higher mitochondrial membrane potentials, and reduced mitochondrial ultrastructure defects. Furthermore, IGF2 administration also increases the overall protein synthesis and decreases the apoptotic index in oocytes from obese mice.

CONCLUSIONS

Collectively, our findings are strongly in favor of adding IGF2 in culture medium to overcome obesity-related meiotic structural-developmental defects by helping ameliorate the known sub-optimal culturing conditions that are currently standard with assisted reproduction technologies.

Investigating of the effects of trophectoderm morphology on obstetrics outcome in 5th day blastocyst transfer in patients with in vitro fertilization

Objective:

Trophectoderm (TE) cells are the first differentiating cells in embryo development and have epithelial features. TE cells, which associate with implantation of the blastocyst into the uterine endometrium, contribute to the formation of the placenta. Inner cells mass (ICM) together with TE cells are used for determining embryo quality. The aim of this study was to investigate the role of TE and ICM cells on pregnancy outcome in 5^th day blastocyst transferred in-vitro-fertilization (IVF) pregnancy.

Material and Methods:

This was a retrospective study using data from all patients who applied for blastocyst transfer IVF between January 2015 and March 2019 at the Reproductive Endocrinology and Infertility Center of Akdeniz University Faculty of Medicine, Department of Obstetrics and Gynecology. ALPHA İstanbul consensus evaluation system was used for grading of the blastocyst. The embryo quality, expansion, ICM and TE morphology of the 5^th day transferred blastocyst was assessed, together with abortion rate, live birth rate, pregnancy complications, and pregnancy outcomes.

Results:

There was a significantly increased risk of preeclampsia (PE) (7.8% vs 1.1%; p=0.041), preterm delivery (PD) (36% vs 17.7%; p=0.037), and antenatal bleeding rates (13.6% vs 5%; p=0.021) in TE-C compared to the TE-A + TE-B blastocysts. Furthermore, a higher rate of obstetric complications was observed in ICM-C compared to ICM-A and B (p=0.003). There was a significant correlation between TE morphology and implantation success, ongoing pregnancy rate, and abortion incidence.

Conclusion:

These results suggest that TE cell morphology is related to implantation success and pregnancy outcomes, especially in terms of the risk of abortion, PE, PD, and antenatal bleeding. It may be advisable to counsel women concerning possible poor obstetric outcome due to poor ICM quality. Future prospective and controlled studies are needed to clarify this association.

Embryo morphology and live birth in the United States

Objective

To determine the best-fit live birth rate per embryo based on maternal age, embryo stage, and embryo morphology.

Design

Retrospective data analysis.

Setting

Fertility clinics.

Patient(s)

The patients included were treated with in vitro fertilization in the United States at clinics reporting data to the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System. We analyzed live birth data of unbiopsied autologous cleavage and blastocyst stage embryos for cycles started from 2016 through 2018. The analysis included 223,377 embryo transfers with a total of 336,888 embryos.

Intervention(s)

None.

Main Outcome Measure(s)

Live birth rate per embryo and rate of multiple gestations per pregnancy.

Result(s)

At the mean maternal age of 34 years, fresh embryos produced live birth rates of 19%, 38%, 26%, and 27% for embryos aged 3, 5, 6, and 7 days, respectively. At the age 34 years, live birth rates for day 5 fresh embryos by overall morphology grade were 43% for good, 30% for fair, and 21% for poor. For the transfer of 2 fresh day 5 blastocysts, the rate of multiple gestations per pregnancy was 47% at 25 years old, 44% at 30 years old, 35% at 35 years old, and 23% at 40 years old.

Conclusion(s)

The analysis of pregnancy data in the Society for Assisted Reproductive Technology database can be used to calculate live birth rates per embryo based on maternal age, embryo age, and morphology. This information can be used for evidence-based decision making, quality control, and planning multicenter studies.

Longitudinal surface measurements of human blastocysts show that the dynamics of blastocoel expansion are associated with fertilization method and ongoing pregnancy

BACKGROUND

Despite all research efforts during this era of novel time-lapse morphokinetic parameters, a morphological grading system is still routinely being used for embryo selection at the blastocyst stage. The blastocyst expansion grade, as evaluated during morphological assessment, is associated with clinical pregnancy. However, this assessment is performed without taking the dynamics of blastocoel expansion into account. Here, we studied the dynamics of blastocoel expansion by comparing longitudinal blastocoel surface measurements using time-lapse embryo culture. Our aim was to first assess if this is impacted by fertilization method and second, to study if an association exists between these measurement and ongoing pregnancy.

METHODS

This was a retrospective cohort study including 225 couples undergoing 225 cycles of in vitro fertilization (IVF) treatment with time-lapse embryo culture. The fertilization method was either conventional IVF, intracytoplasmic sperm injection (ICSI) with ejaculated sperm or ICSI with sperm derived from testicular sperm extraction (TESE-ICSI). This resulted in 289 IVF embryos, 218 ICSI embryos and 259 TESE-ICSI embryos that reached at least the full blastocyst stage. Blastocoel surface measurements were performed on time-lapse images every hour, starting from full blastocyst formation (tB). Linear mixed model analysis was performed to study the association between blastocoel expansion, the calculated expansion rate (µm²/hour) and both fertilization method and ongoing pregnancy.

RESULTS

The blastocoel of both ICSI embryos and TESE-ICSI embryos was significantly smaller than the blastocoel of IVF embryos (beta -1121.6 µm²; 95% CI: -1606.1 to -637.1, beta -646.8 µm²; 95% CI: -1118.7 to 174.8, respectively). Still, the blastocoel of transferred embryos resulting in an ongoing pregnancy was significantly larger (beta 795.4 µm²; 95% CI: 15.4 to 1575.4) and expanded significantly faster (beta 100.9 µm²/hour; 95% CI: 5.7 to 196.2) than the blastocoel of transferred embryos that did not, regardless of the fertilization method.

CONCLUSION

Longitudinal blastocyst surface measurements and expansion rates are promising non-invasive quantitative markers that can aid embryo selection for transfer and cryopreservation.

TRIAL REGISTRATION

Our study is a retrospective observational study, therefore trial registration is not applicable.

Lycopene Supplementation to Serum-Free Maturation Medium Improves In Vitro Bovine Embryo Development and Quality and Modulates Embryonic Transcriptomic Profile

Bovine embryos are typically cultured at reduced oxygen tension to lower the impact of oxidative stress on embryo development. However, oocyte in vitro maturation (IVM) is performed at atmospheric oxygen tension since low oxygen during maturation has a negative impact on oocyte developmental competence. Lycopene, a carotenoid, acts as a powerful antioxidant and may protect the oocyte against oxidative stress during maturation at atmospheric oxygen conditions. Here, we assessed the effect of adding 0.2 μM lycopene (antioxidant), 5 μM menadione (pro-oxidant), and their combination on the generation of reactive oxygen species (ROS) in matured oocytes and the subsequent development, quality, and transcriptome of the blastocysts in a bovine in vitro model. ROS fluorescent intensity in matured oocytes was significantly lower in the lycopene group, and the resulting embryos showed a significantly higher blastocyst rate on day 8 and a lower apoptotic cell ratio than all other groups. Transcriptomic analysis disclosed a total of 296 differentially expressed genes (Benjamini–Hochberg-adjusted p < 0.05 and ≥ 1-log2-fold change) between the lycopene and control groups, where pathways associated with cellular function, metabolism, DNA repair, and anti-apoptosis were upregulated in the lycopene group. Lycopene supplementation to serum-free maturation medium neutralized excess ROS during maturation, enhanced blastocyst development and quality, and modulated the transcriptomic landscape.

Developmental stage and morphology of the competent blastocyst are associated with sex of the child but not with other obstetric outcomes: a multicenter cohort study

STUDY QUESTION

Are transfer day, developmental stage and morphology of the competent blastocyst in pregnancies leading to live birth associated with preterm birth, birthweight, length at birth and sex of the child?

SUMMARY ANSWER

A high score in blastocyst developmental stage and in trophectoderm (TE) showed a significant association with the sex of the child, while no other associations with obstetric outcomes were observed.

WHAT IS KNOWN ALREADY

The association between blastocyst assessment scores and obstetric outcomes have been reported in small single-center studies and the results are conflicting.

STUDY DESIGN, SIZE, DURATION

Multicenter historical cohort study based on exposure data (transfer day (blastocyst developmental stage reached by Day 5 or Day 6)) blastocyst developmental stage (1-6) and morphology (TE and inner cell mass (ICM): A, B, C)) and outcome data (preterm birth, birthweight, length at birth, and sex of the child) from women undergoing single blastocyst transfer resulting in a singleton pregnancy and live birth.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data from 16 private and university-based facilities for clinical services and research were used. A total of 7246 women, who in 2014-2018 underwent fresh-embryo transfer with a single blastocyst or frozen-thawed embryo transfer (FET) with a single blastocyst resulting in a singleton pregnancy were identified. Linking to the Danish Medical Birth Registry resulted in a total of 4842 women with a live birth being included. Cycles with pre-implantation genetic testing and donated gametes were excluded. The analyses were adjusted for female age (n = 4842), female BMI (n = 4302), female smoking (n = 4290), parity (n = 4365), infertility diagnosis (n = 4765), type of treatment (n = 4842) and center (n = 4842); some analyses additionally included gestational age (n = 4368) and sex of the child (n = 4833).

MAIN RESULTS AND THE ROLE OF CHANCE

No statistically significant associations between blastocyst assessment scores (transfer day, developmental stage, TE, ICM) and preterm birth (8.3%) or birthweight (mean 3461.7 g) were found. The adjusted association between blastocysts with a TE score of C and a TE score of A and length at birth (mean 51.6 cm) were statistically significant (adjusted mean difference 0.4 cm (95% CI: 0.02; 0.77)). Blastocysts transferred with developmental stage score 5 compared to blastocysts transferred with score 3 had a 34% increased probability of being a boy (odds ratio (OR) 1.34 (95% CI: 1.09; 1.64). Further, TE score B blastocysts compared to TE score A blastocysts had a 31% reduced probability of being a boy (OR 0.69 (95% CI: 0.60; 0.80)).

LIMITATIONS, REASONS FOR CAUTION

It is possible that some residual confounding remains.

WIDER IMPLICATIONS OF THE FINDINGS

Blastocyst selection during ART does not appear to introduce any negative effects on obstetric outcome. Therefore, clinicians and patients can be reassured that the assessment scores of the selected blastocyst will not in themselves pose a risk of preterm birth or affect birthweight and the length at birth.

STUDY FUNDING/COMPETING INTEREST(S)

Unrestricted grant from Gedeon Richter Nordics AB, Sweden. None of the authors have any competing interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Obesity and oocyte quality: Significant implications for ART and Emerging mechanistic insights

The prevalence of obesity in adults worldwide, and specifically in women of reproductive age, is concerning given the risks to fertility posed by the increased risk of type 2 diabetes, metabolic syndrome and other non-communicable diseases. Obesity has a multi-systemic impact in female physiology that is characterized by the presence of oxidative stress, lipotoxicity, and the activation of pro-inflammatory pathways, inducing tissue-specific insulin resistance and ultimately conducive to abnormal ovarian function. A higher body mass is linked to Polycystic Ovary Syndrome, dysregulated menstrual cycles, anovulation, and longer time to pregnancy, even in ovulatory women. In the context of ART, compared to women of normal BMI, obese women have worse outcomes in every step of their journey, resulting in reduced success measured as live birth rate. Even after pregnancy is achieved, obese women have a higher chance of miscarriage, gestational diabetes, pregnancy complications, birth defects, and most worryingly, a higher risk of stillbirth and neonatal death. The potential for compounding effects of ART on pregnancy complications and infant morbidities in obese women has not been studied. There is still much debate in the field on whether these poorer outcomes are mainly driven by defects in oocyte quality, abnormal embryo development or an unaccommodating uterine environment, however the clinical evidence to date suggests a combination of all three are responsible. Animal models of maternal obesity shed light on the mechanisms underlaying the effects of obesity on the peri-conception environment, with recent findings pointing to lipotoxicity in the ovarian environment as a key driver of defects in oocytes that have not only reduced developmental competence but long-lasting effects in offspring health.

Focus on time-lapse analysis: blastocyst collapse and morphometric assessment as new features of embryo viability

The main goal of assisted reproductive technology (ART) is to achieve a healthy singleton live birth after the transfer of one embryo. A major objective of IVF scientists has always been to use adequate criteria for selecting the embryo for transfer according to its implantation potential. Indeed, embryo quality is usually assessed by evaluating visual morphology, which relies on the removal of the embryo from the incubator and might include inter- and intra-evaluator variation among embryologists. Recently, an advancement in embryo culture has taken place with the introduction of a new type of incubator with an integrated time-lapse monitoring system, which enables embryologists to analyse the dynamic events of embryo development from fertilization to blastocyst formation. This novel practice is rapidly growing and has been used in many IVF centres worldwide. Therefore, the main aim of this review is to present the benefits of time-lapse monitoring in a modern embryology laboratory; in particular, we discuss blastocyst collapse and morphometric blastocyst assessment, and analyse their association with embryo viability and implantation potential. In addition, we highlight preliminary studies involving artificial intelligence and machine learning models as non-invasive markers of clinical pregnancy.

Euploid day 7 blastocysts of infertility patients with only slow embryo development have reduced implantation potential

RESEARCH QUESTION

What is the reproductive potential of embryos that achieve blastulation on day 7 followed by preimplantation genetic testing for aneuploidies (PGT-A) for infertility patients with slow embryo development?

DESIGN

This was a retrospective cohort study in a private IVF clinic of consecutive female infertility patients (n = 2966) aged 24-48 (36.3 ± 3.8) years who underwent frozen embryo transfer (FET) of a single euploid blastocyst.

RESULTS

The women underwent single euploid FET of an embryo that achieved blastulation on day 5 (n = 1880), day 6 (n = 986) or day 7 (n = 100). Day 7 embryos resulted in lower implantation and live birth rates compared with both day 5 and day 6 embryos (P < 0.001). The day 5, day 6 and day 7 groups had 68.5%, 55.2% and 36.0% live birth rates, respectively. The day 7 group was older than the day 5 group (P < 0.001); comparing age-matched cohorts, the day 7 group still had lower implantation and live birth rates (P < 0.0001 and P < 0.001, respectively). Embryo grade was unrelated to live birth rates. Day 7 embryos of expansion grade 5 or 6 or trophectoderm grade A were more likely to be euploid compared with expansion grade 3 or trophectoderm grade B.

CONCLUSIONS

Euploid day 7 embryos represented reduced implantation potential, even when controlling for maternal age. Of all day 7 embryos that underwent PGT-A, euploidy was associated with expansion grade 5 or 6 and trophectoderm grade A. These results can help providers manage patient expectations in cases where infertile women have slow embryo development.

Effect of lycopene supplementation to bovine oocytes exposed to heat shock during in vitro maturation

We investigated the effect of the antioxidant lycopene supplemented into the in vitro maturation medium (TCM-199 with 20 ng/mL epidermal growth factor and 50 mg/mL gentamycin) in a heat shock (HS) model to mimic in vivo heat stress conditions. Bovine cumulus-oocyte complexes were supplemented with 0.2 μM lycopene (or not supplemented; control) under HS (40.5 °C) and non-HS (NHS; 38.5 °C) during maturation. After 22 h of maturation, we evaluated the nuclear status of the oocytes, the level of reactive oxygen species (ROS) production, and the respective blastocyst development and quality (via differential staining). Data were fitted in logistic and linear regression models, and the replicates were set as a random effect. The nuclear maturation was higher in NHS (84.0 ± 3.2%; least square mean ± standard error) than HS control (60.4 ± 4.3%; P < 0.001). Remarkably, the nuclear maturation in HS lycopene (71.7 ± 4.1%) was similar to NHS control (P = 0.7). Under HS conditions lycopene reduced ROS production (27.4 ± 4.8; relative fluorescence units (RFU)) in comparison to HS control (33.8 ± 1.8 RFU; P = 0.009). However, the ROS production in NHS lycopene (18.9 ± 2.0 RFU) was similar to NHS control (18.7 ± 1.8 RFU; P = 0.9). The cleavage rate in HS lycopene (76.1 ± 3.3%) was not lower than NHS lycopene (83.3 ± 2.5%; P > 0.1). On the day 8 of embryo development, the blastocyst rate was higher for NHS lycopene (55.2 ± 4.7%) versus NHS control (44.5 ± 4.7%; P = 0.04), but under HS the day 8 blastocyst rate was similar between control (29.9 ± 4.2%) and lycopene (32.3 ± 4.2%; P = 0.9). Lycopene supplementation increased the cell number of the embryos (total cell, trophectoderm, and inner cell mass numbers) under NHS conditions (P > 0.03). The apoptotic cell ratio was lower in lycopene (NHS and HS) versus control (NHS and HS) (P > 0.04). Lycopene has the ability to scavenge oocyte ROS and improved the cleavage rate of embryos under HS conditions. However, this could not be translated to a higher blastocyst development, which remained lower under HS. Results of our study indicate that antioxidant supplementation like lycopene during the maturation of bovine cumulus-oocyte complexes may be routinely used to improve blastocyst rate and quality under standard maturation conditions.

Effect of Age and Embryo Morphology on Live Birth Rate After Transfer of Unbiopsied Blastocysts

OBJECTIVE

To determine the rate of live birth per blastocyst based on morphology and oocyte age using data from a single center.

METHODS

This is a mathematical analysis and model building study of autologous blastocyst stage embryo transfers at a University-affiliated center. A total of 448 blastocyst stage embryos were transferred in 244 fresh and frozen embryo transfers from May 2015 through April 2018. Blastocyst morphology was divided into good, fair, and poor overall morphology grades. Each embryo transfer was modeled as an equation equating the sum of the unknown live birth rates of the transferred embryos to the number of live births that resulted. The least squares solution to the system of embryo transfer equations was determined using linear algebra.

RESULTS

Trophectoderm morphology was a better predictor of live birth rate than inner cell mass morphology. Embryos graded AA/AB/BA (good) had the highest live birth rates followed by BB/CB (fair), and BC/CC (poor). In our youngest age group (25-32 years) live birth rates per embryo were 51% for good, 39% for fair, and 25% for poor quality embryos. In our oldest age group (40-44 years) the live birth rates per embryo were 22% for good, 14% for fair, and 8% for poor quality embryos.

CONCLUSIONS

These techniques can help analyze small datasets such as those from individual clinics to aid in determining the ideal number of embryos to transfer to achieve live birth while limiting the risk of multiple gestations.

The morphokinetic signature of mosaic embryos: evidence in support of their own genetic identity

OBJECTIVE

To provide full morphokinetic characterization of embryos ranked with different degrees of chromosomal mosaicism.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated private in vitro fertilization clinic.

PATIENT(S)

We analyzed 1,511 embryos from 424 intracytoplasmic sperm injection cycles by culturing embryos in a time-lapse imaging system and performing next-generation sequencing. We assessed 106 mosaic embryos.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Comparison of chromosomal, morphological, and morphokinetic characteristics of blastocysts classified as euploid, aneuploid, low-degree mosaic (30% to <50% aneuploid cells in trophectoderm biopsy), and high-degree mosaic (50% to <70% aneuploid cells in trophectoderm biopsy). Statistical analysis was performed using χ2, Kruskal-Wallis, or analysis of variance tests according to data type and distribution. A two-way random effects model was used to calculate interoperator correlation of annotations, and a logistic mixed effects model was performed to evaluate the effect of confounders on morphokinetic timing.

RESULT(S)

The mosaicism rate was ∼7% regardless of parental age. Mosaicism and uniform aneuploidies were not evenly distributed across chromosomes. The percentage of high-quality blastocysts significantly decreased from euploid (66.9%) to mosaic (52.8%) and aneuploid (47.7%). Aneuploid blastocysts significantly delayed development compared with euploid blastocysts in start of compaction (median, 84.72 hours postmicroinjection [hpm], interquartile range [IQR], 13.2; vs. median, 82.10 hpm, IQR, 11.5), start of blastulation (median, 101 hpm; IQR, 11.7; vs. median, 98.29 hpm, IQR, 10.5), and timing of blastocyst (median, 108.04 hpm, IQR, 11.50; vs. median, 104.71 hpm, IQR, 11.35). However, embryo morphokinetics were not correlated to the degree of mosaicism or to a mosaicism configuration that was apt for embryo transfer.

CONCLUSION(S)

Morphokinetic timing of mosaic embryos overlaps with that of euploid and aneuploid embryos, which may reflect their unique genetic and developmental identity. Although this suggests mosaic embryos are not simply a misdiagnosis by-product, further studies are needed to reveal the true identity of this particular type of embryo.

Effect of age and morphology on sustained implantation rate after euploid blastocyst transfer

RESEARCH QUESTION

What impact does maternal age and embryo morphology have on sustained implantation rates of euploid blastocysts?

DESIGN

This was a retrospective analysis of sustained implantation rates of euploid blastocysts stratified by maternal age and morphology. The primary analysis included 208 embryo transfers with a total of 229 embryos transferred from January 2017 through August 2020.

RESULTS

For all ages the sustained implantation rates for day 5 good quality blastocysts were higher than for day 5 fair, day 5 poor and day 6 blastocysts. At a maternal age of 36 years the best-fit sustained implantation rates were 86% for day 5 good quality blastocysts, 64% for day 5 fair, 63% for day 5 poor, and 51% for all day 6 blastocysts analysed as one group. When controlling for morphology and day of biopsy, there were higher sustained implantation rates for euploid embryos of younger patients compared with older patients. The best-fit sustained implantation rates for age 33 compared to age 39 years were 86% versus 80% for day 5 good, 71% versus 62% for day 5 fair, 59% versus 55% for day 5 poor, and 81% versus 46% for all day 6.

CONCLUSIONS

There was a clinically significant higher sustained implantation rate at all ages for euploid day 5 good quality embryos compared with day 5 fair, day 5 poor and day 6 embryos.

A validated model for predicting live birth after embryo transfer

Accurately predicting the probability of live birth and multiple gestations is important for determining a safe number of embryos to transfer after in vitro fertilization. We developed a model that can be fit to individual clinic data for predicting singleton, twin, and total live birth rates after human embryo transfer. The predicted and observed rates of singleton and twin deliveries were compared in a tenfold cross-validation study using data from a single clinic. The model presented accounts for patient age, embryo stage (cleavage or blastocyst), type of transfer cycle (fresh or frozen) and uterine/universal factors. The standardized errors for rates of singleton and twin deliveries were normally distributed and the mean errors were not significantly different from zero (all p > 0.05). The live birth rates per embryo varied from as high as 43% for fresh blastocysts in the 35-year-old age group to as low as 1% for frozen cleavage stage embryos in the 43-year-old age group. This quantitative model or a simplified version can be used for clinics to generate and analyze their own data to guide the number of embryos to transfer to limit the risk of multiple gestations.

Integrated pseudotime analysis of human pre-implantation embryo single-cell transcriptomes reveals the dynamics of lineage specification

Understanding lineage specification during human pre-implantation development is a gateway to improving assisted reproductive technologies and stem cell research. Here we employ pseudotime analysis of single-cell RNA sequencing (scRNA-seq) data to reconstruct early mouse and human embryo development. Using time-lapse imaging of annotated embryos, we provide an integrated, ordered, and continuous analysis of transcriptomics changes throughout human development. We reveal that human trophectoderm/inner cell mass transcriptomes diverge at the transition from the B2 to the B3 blastocyst stage, just before blastocyst expansion. We explore the dynamics of the fate markers IFI16 and GATA4 and show that they gradually become mutually exclusive upon establishment of epiblast and primitive endoderm fates, respectively. We also provide evidence that NR2F2 marks trophectoderm maturation, initiating from the polar side, and subsequently spreads to all cells after implantation. Our study pinpoints the precise timing of lineage specification events in the human embryo and identifies transcriptomics hallmarks and cell fate markers.

The antioxidant dieckol reduces damage of oxidative stress-exposed porcine oocytes and enhances subsequent parthenotes embryo development

This study investigated the effect of the antioxidant dieckol, a component of Ecklonia cava, on maturation and developmental competence of porcine oocytes exposed to oxidative stress in vitro. Oocytes were matured in in vitro maturation (IVM) medium containing various concentrations of dieckol. The blastocyst formation rate was highest in the 0.5 μM dieckol-treated (0.5 DEK) group. The reactive oxygen species level was decreased, and the level of glutathione and expression of antioxidant genes (NFE2L, SOD1, and SOD2) at metaphase II were increased in the 0.5 DEK group. Abnormal spindle organization and chromosome misalignment were prevented in the 0.5 DEK group. Expression of maternal markers (CCNB1 and MOS) and activity of p44/42 mitogen-activated protein kinase were increased in the 0.5 DEK group. After parthenogenetic activation, the total number of cells per blastocyst was increased and the percentage of apoptotic cells was decreased in the 0.5 DEK group. Expression of development-related genes (CX45, CDX2, POU5F1, and NANOG), antiapoptotic genes (BCL2L1 and BIRC5), and a proapoptotic gene (CASP3) were altered in the 0.5 DEK group. These results indicate that the antioxidant dieckol improves IVM and subsequent development of porcine oocytes and can be used to improve the quality of oocytes under peroxidation experimental conditions.

Euploidy rates are not affected when embryos are cultured in a continuous (CCM) or sequential culture medium (SCM): a sibling oocyte study

PURPOSE

To determine if euploidy rates and embryo development differ when blastocysts are cultured in CCM or SCM.

METHOD

A single-center retrospective observational study was performed from September 2018 to March 2019. Patients [23-46 years] with at least four fresh mature oocytes (MII) without severe male factor infertility were included. Sibling MII were injected and cultured in Global®Total®LP (CCM) or Sage Quinn's Advantage® Cleavage and Blastocyst media (SCM) under 6% CO₂, 5% O₂, and 89% N₂. Fertilization, cleavage, day (D) 5 blastulation, usable blastocyst (blastocysts biopsied/normally fertilized oocytes), and euploidy rates were recorded. Blastocysts were graded prior to trophectoderm (TE) biopsy on D5, 6, or 7 for genetic testing and mitochondrial DNA (mtDNA) quantification.

RESULTS

According to clinical practice, 1452 MII were randomly distributed: 751 in CCM and 701 in SCM. No differences were observed in fertilization and cleavages rates for CCM and SCM (77.4% vs 75.5%, p = 0.429 and 97.6% vs 99.1%, p = 0.094, respectively). Blastulation rate on D5 was higher in CCM (70.6% vs 62.2, p = 0.009); however, usable blastocyst rates were comparable (CCM: 58.3% vs SCM: 56.7%, p = 0.625). From a Poisson regression model adjusted for confounding factors, euploidy rates were not different between media (aOR = 1.18, [0.94-1.48], p = 0.157). Euploid blastocyst's mtDNA values were similar (CCM: 32.2, [30.5, 34.1] and SCM: 33.5, [31.8, 35.2], p = 0.345) and top-quality blastocysts (AA/BA) were increased in SCM (OR=1.04, [1.00-1.09], p = 0.037).

CONCLUSION

Under controlled in vitro conditions, euploidy rates and embryo development are comparable when embryos are cultured in CCM or SCM.

The Morphology of Inner Cell Mass Is the Strongest Predictor of Live Birth After a Frozen-Thawed Single Embryo Transfer

Background

The scoring system for human blastocysts is traditionally based on morphology; however, there are controversies on the effect of morphology parameters on pregnancy outcomes. The aim of this study is to evaluate the predicting value of each morphology parameter on pregnancy outcomes in a setting of single embryo transfer.

Methods

This is a retrospective cohort study on patients undergoing frozen-thawed single blastocyst transfer at our center, between Jan. 2009 and Dec. 2018. A total of 10,482 cycles were analyzed. The blastocysts were scored according to the expansion and hatching status, morphology of inner cell mass (ICM), and cells of trophectoderm (TE). The primary outcome measure was live birth rate. One-way analysis of variance, chi-square test, and multiple logistic regression were used for statistical analysis.

Results

The clinical pregnancy rate was lower in the blastocysts of stage 3 (48.15%), compared with those of stage 4 (56.15%), stage 5 (54.91%), and stage 6 (53.37%). The live birth rate was lower in the blastocysts of stage 3 (37.07%), compared with those of stage 4 (44.21%) and stage 5 (41.67%). The rates of clinical pregnancy (A: 66.60%, B: 53.25%, C: 39.33%) and live birth (A: 54.62%, B: 41.29%, C: 28.45%) were both decreased with decreasing grade of ICM morphology, and these differences were pairwise significant. The miscarriage rate of blastocysts with ICM grade A was lower, compared with ICM grade C (17.53 vs. 27.66%). Blastocysts with TE morphology of C had lower rates of clinical pregnancy (43.53%) and live birth (32.57%), compared with those with TE morphology of A and B (clinical pregnancy rate: 64.26% for A, 58.11% for B; live birth rate: 52.74% for A, 45.64% for B). There were no significant differences in rates of clinical pregnancy, live birth, and miscarriage between the blastocysts with TE grade A and B.

Conclusions

The blastocyst expansion stage, ICM grade, and TE grade are all associated with pregnancy outcomes. ICM grade is the strongest predictor of live birth. A blastocyst with stage 4-5, ICM grade A, and TE grade A/B should be given priority for single embryo transfer.

Blastocyst age, expansion, trophectoderm morphology, and number cryopreserved are variables predicting clinical implantation in single blastocyst frozen embryo transfers in freeze-only-IVF

PURPOSE

To determine which blastocyst assessment variables predict clinical implantations in single blastocyst frozen embryo transfers (FET) of freeze-only-IVF cycles, following improved vitrified-warmed blastocyst survival and developmental competence preservation.

METHOD

In this retrospective cohort study performed at a single private IVF center, the pregnancy outcomes of 1795 single blastocyst FET cycles were analyzed, from freeze-only-IVF retrievals performed between January 2017 and January 2020. Stepwise forward logistic regressions with clinical implantation (i.e., normal gestational sac and cardiac activity) as dependent variable were performed to identify the significant predictors. All blastocysts were vitrified using Cryotop technology, with before transfer (post-warming) blastocyst morphology scores used in all analyses.

RESULT(S)

The 1795 blastocysts transferred were vitrifıed on embryo days 4 (1057), 5 (716), and 6 (22). The overall clinical implantation rate was 50.9%; however, using blastocyst age and blastocyst morphological score the clinical implantation rates increased from 49.0% (day-4 1 and 2) and 25.2% (day-5 1 and 2) to 71.2% (day-4 4AA) and 64.3% (day-5 4AA), respectively. Whereas full (≥3) blastocysts with scores of AA and BA had similar clinical implantation rates (66.2 vs. 66.7%), the rate of full blastocysts with scores of AB was lower (58.9%). In stepwise forward logistic regressions, female age, blastocyst age, blastocyst expansion score, blastocyst trophectoderm score, and number of blastocysts vitrified were significant predictors of clinical implantation.

CONCLUSION(S)

Using blastocyst age and before transfer blastocyst expansion and trophectoderm morphology scores to select blastocysts, clinical implantation rates greater than 70% could be achieved for top-scoring blastocysts.

Clinical pregnancy is significantly associated with the blastocyst width and area: a time-lapse study

In order to maintain pregnancy rates following single embryo transfer, optimisation of embryo culture and selection is vital. Time-lapse monitoring (TLM) has the potential to play a crucial role by providing sequential images of embryo development and minimal disturbance. Therefore, in this study morphometric assessment of blastocyst area and maximum width was performed in order to evaluate if these parameters are associated with pregnancy outcomes in IVF/ICSI cycles. This is a retrospective study of 664 patients who had elective single blastocyst transfer (eSBT). The EmbryoScope drawing tools were used to measure specific variables such as the maximum blastocyst width and blastocyst area. Our results show that women who were pregnant had significantly (P < 0.01) larger blastocyst width [median (range) μm] 184 (125-239) versus non-pregnant, 160 (120-230)] and area [median (range) μm²] 26099 (12101-45,280) versus non-pregnant women, 22,251 (10992-37,931)]. A univariate logistic regression performed showed that blastocyst width [(OR = 1.026, 95% CI = (1.019, 1.033)] was significant (P < 0.01) and for every μm increase of blastocyst width, the odds of clinical pregnancy increase by 2.6%. A univariate logistic regression performed showed that blastocyst area [(OR = 1.00008, 95% CI = (1.00006, 1.00011)] was significant with P < 0.01. For every μm² increase of blastocyst area, our data showed the odds of clinical pregnancy increase by 0.008%. Hosmer-Lemeshow tests of calibrations were performed to verify calibration. Although our findings show a clear correlation between blastocyst dimensions and the clinical pregnancy rate, further studies are necessary to confirm these observations.

Blastocyst morphology has no relationship with serum β-hCG levels and live birth rates once pregnant

OBJECTIVE

What is the role of blastocyst morphology on day16 β-hCG serum levels and pregnancy outcomes among patients who conceived through IVF cycles with single fresh Gardner's scored blastocyst transfers.

STUDY DESIGN

A retrospective cohort study conducted at a single academic fertility center between January 2013 and December 2017. A total of 643 pregnancies were included in the study.

RESULTS

The patients were divided into 5 groups according to Gardner's blastocysts grade of the ICM and the TE (grade), and into 4 groups according to blastocyst Gardner's degree of blastocoel expansion (stage). No significant differences were found between the different morphologic groups and day16 β-hCG serum levels, clinical pregnancy rates and live births. A weak significant correlation was observed between Gardner's blastocysts grade and day 16 β-hCG (Correlation Coefficient r= -0.098, p = .014) this correlation remained significant after controlling for confounders. (r= -0.099 p = . 013). A weak significant correlation was observed between Gardner's stage and day 16 β-hCG (Correlation Coefficient r = 0.086, p = 0.029) this correlation lost significance after controlling for confounders. (r = 0.055, p = 0.340). When evaluating predictors of live birth using multivariate logistic regression, blastocyst grade (p = 0.33) and stage (p = 0.65), at transfer, were not associated with live births, when controlling for confounding effects.

CONCLUSION

Once the patient conceives after IVF with single blastocyst, none of the morphological parameters have a strong impact on the day16 serum level of β-hCG. Among women who conceived, blastocyst grade and stage were not associated with live births.

High-quality Cleavage Embryo versus Low-quality Blastocyst in Frozen-thawed Cycles: Comparison of Clinical Outcomes

This study compared the clinical outcomes of the frozen-thawed cycles of high-quality cleavage embryos with low-quality blastocysts to provide a reference for the choice of frozen-thawed embryo transfer schemes and to improve clinical pregnancy rates. A retrospective analysis was performed on the clinical data of patients undergoing frozen-thawed embryo transfer at the Reproductive Medicine Center of Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology from 2016 to 2017. In total, 845 cases were divided into a high-quality cleavage embryo group (group A) and a low-quality blastocyst group (group B). Each group was further divided into subgroups based on the number of transplants. Group A was categorized into two subgroups comprising of 94 cases in subgroup A1 (1 high-quality 8-cell group) and 201 cases in subgroup A2 (2 high-quality 8-cell group). Group B was divided into four subgroups consisting of 73 cases in subgroup B1 (D53BC group), 65 cases in subgroup B2 (D54BC group), 110 cases in subgroup B3 (D63BC group), and 282 cases in subgroup B4 (D64BC group). The pregnancy outcomes and neonatal outcomes between the groups were compared. The clinical pregnancy rates (56.72% and 60.00%) and live birth rates (47.76% and 46.15%) in subgroups A2 and B2 showed no significant differences, but these rates were significantly higher in subgroups A2 and B2 than in the rest subgroups (P<0.05). The multiple birth rate (26.32%) in the subgroup A2 was significantly higher than that in the rest subgroups (P<0.05). There were no statistically significant differences in the abortion rates among all groups (P>0.05). In terms of neonatal outcomes, there were no statistically significant differences in the proportion of premature births, sex ratios, and birth defects among the low-weight and gigantic infants (P>0.05). Transplanting two high-quality cleavage embryos during the frozen-thawed embryo transfer cycles could significantly increase clinical pregnancy rates and live birth rates, but at the same time, it also increased the risks of multiple births and complications to mothers and infants. The D54BC subgroup had the most significant advantages among all groups (P<0.05). The rest low-quality blastocysts had clinical outcomes similar to the single high-quality cleavage embryo group.

Association between women's age and stage, morphology, and implantation of the competent blastocyst: a multicenter cohort study

OBJECTIVE

To study if the age of women undergoing assisted reproductive technology treatment associates with stage, morphology, and implantation of the competent blastocyst.

DESIGN

Multicenter historical cohort study based on exposure (age) and outcome data (blastocyst stage and morphology and initial human chorionic gonadotrophin [hCG] rise) from women undergoing single blastocyst transfer resulting in singleton pregnancy/birth.

SETTING

Sixteen private and university-based facilities.

PATIENT(S)

In this study, 7,246 women who, between 2014 and 2018, underwent controlled ovarian stimulation (COS) or frozen-thawed embryo transfer (FET) with a single blastocyst transfer resulting in singleton pregnancy were identified. Linking data to the Danish Medical Birth Registry resulted in a total of 4,842 women with a live birth being included.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The competent blastocyst development stage (1-6), inner cell mass (A, B, C), trophectoderm (A, B, C), and initial serum hCG value.

RESULT(S)

Adjusted analysis of age and stage in COS treatments showed that for every 1-year increase in age there was a 5% reduced probability of the competent blastocyst assessed as being in a high stage at transfer. Comparison between hCG values in women 18-24 years and 25-29 years in both COS and FET showed significantly lower levels in the youngest women.

CONCLUSION(S)

The initial hCG rise was influenced by the age of the woman, with an identical pattern for hCG values in COS and FET treatments. In COS, the competent blastocyst had a reduced stage with increasing women's age.

Necessity is the mother of invention and the evolutionary force driving the success of in vitro fertilization

During the last few decades, millions of healthy children have been born with the aid of in vitro fertilization (IVF). This success belies the fact that IVF treatment is comprised of a complex series of interventions starting with a customized control ovarian stimulation protocol. This is followed by the induction of oocyte maturation, the retrieval of mature oocytes and in vitro fertilization, which often involves the microinjection of a single sperm into the oocyte. After fertilization, the resulting embryos are cultured for up to 7 days. The best embryos are transferred into the uterus where the embryo implants and hopefully develops into a healthy child. However, frequently the best embryos are biopsied and frozen. The biopsied cells are analyzed to identify those embryos without chromosomal abnormalities. These embryos are eventually thawed and transferred with pregnancy rates as good if not better than embryos that are not biopsied and transferred in a fresh cycle. Thus, IVF treatment requires the coordinated efforts of physicians, nurses, molecular biologists and embryologists to conduct each of these multifaceted phases in a seamless and flawless manner. Even though complex, IVF treatment may seem routine today, but it was not always the case. In this review the evolution of human IVF is presented as a series of innovations that resolved a technical hurdle in one component of IVF while creating challenges that eventually lead to the next major advancement. This step-by-step evolution in the treatment of human infertility is recounted in this review.

Transfers of lower quality embryos based on morphological appearance result in appreciable live birth rates: a Canadian center's experience

Objective

To determine the reproductive outcomes resulting from transfer of lower-grade blastocysts to support the practice of cryopreserving and transferring lower-grade embryos.

Design

Retrospective chart review.

Setting

Single infertility center.

Patient(s)

Women who have undergone a fresh (n = 570) or frozen (n = 885) transfer of a single blastocyst embryo between December 2013 and December 2018.

Intervention(s)

None.

Main Outcome Measure(s)

The primary outcome was live birth rate. The secondary outcomes included implantation rate, ongoing pregnancy rate, associations with inner cell mass (ICM) and trophectoderm epithelium (TE) grades determined by morphological assessment, and antenatal/perinatal complications.

Results

Reproductive outcomes directly correlated with embryo quality. Transfers of AA embryos resulted in a 41.4% live birth rate compared to 31.1% for BB embryos and 13.3% for CC embryos. The TE grade was significantly associated with the live birth rate. Embryos with a TE grade of “B” had an odds ratio of 0.677 and embryos with a TE grade of “C” had an odds ratio of 0.394 compared to embryos with a TE grade of “A” for live birth.

Conclusion

Embryos with a TE “C” grade should be considered for transfer and cryopreservation, as they are shown to result in appreciable live birth rates. Such treatment should involve a thorough discussion with patients, however, as these live birth rates are significantly lower than those associated with higher-grade embryos.

Association between blastocyst morphology and live birth rate following frozen-thawed single blastocyst transfer: Results from a 5-year retrospective analysis of 2593 cryopreserved blastocysts

AIM

Our aim was to investigate associations between blastocyst morphology parameters and live birth outcome and to make possible additional recommendations for existing embryo selection strategies.

METHODS

This retrospective cohort study included 2593 frozen-thawed single blastocyst transfers (SBT) cycles from 2012 to 2016. Multivariable logistic regression model was used to analyze the independent predictive effectiveness of blastocyst parameters for live birth rate (LBR).

RESULTS

The participants enrolled in the present study were 32 (28-35) years old with a median body mass index of 21.20 (19.60-23.40) kg/m² , among whom 1058 (40.8%) women had live births. Among the three blastocyst morphology parameters, we found only inner cell mass grade and trophectoderm cell grade had significant effects on LBR (P < 0.001). When adjusting for potential confounders in a multivariable logistic regression model, the expansion and hatching (EH) stage of blastocoel also showed obvious correlation with LBR. Blastocysts at EH stage 4-5 had a significantly higher LBR than that at stage 3 (P < 0.05). Additionally, the timing of blastulation was also an important predictor of LBR. Blastocysts vitrified on day 6 and day 7 yielded a lower LBR than that vitrified on day 5 (P < 0.001).

CONCLUSION

The timing of blastulation and all blastocyst morphology parameters were associated with LBR independently. Although the most important parameter for predicting clinical outcomes remains undetermined, the timing of blastulation was a stable predictor of live birth for frozen-thawed SBT.

Pronuclear and blastocyst morphology are associated age-dependently with embryo ploidy in in vitro fertilization cycles

This retrospective study aimed to assess the relationship between standard markers of embryo morphology, maternal age and blastocyst ploidy determined by trophectoderm (TE) biopsy and Next-generation Sequencing (NGS). A total of 774 oocytes and embryos from 288 PGT-A cycles were scored for pronuclear, cleavage stage and blastocyst morphology. Pronuclear oocytes aligned between the nuclei and presenting equal number of nucleolus precursor bodies (NPBs) were designated Z1, oocytes showing equal number of NPBs, but not aligned, as Z2 while Z3 oocytes had an unequal number of NBPs between the nuclei or NPBs aligned in one nucleus and non-aligned in the other. Pronuclear oocytes with unequal-sized or non-aligned nuclei were designated Z4. Blastocysts were graded as BL1 (AA, AB or BA), BL2 (BB or CB) and BL3 (BC or CC) based on the combination of inner cell mass (ICM) and TE scores. Pronuclear and blastocyst morphology were correlated with aneuploidy in a < 40-year-old group (p < 0.01 and p < 0.05, respectively), but not in those ≥40 years. Interestingly, BL3 blastocysts classified as Z1 or Z3-Z4 on day-1 had different aneuploidy rates (BL3/Z1 = 46.7% vs. BL3/Z3-Z4 = 90.0%, p < 0.05). In summary, our data showed that pronuclear and blastocyst morphology are associated with blastocyst ploidy in younger patients. This may help embryo selection for embryo transfer and decision-making on which blastocysts should be biopsied in PGT-A cycles.

Transfer the best and biopsy the rest? Blastocyst euploidy rates differ by morphology and day of biopsy

PURPOSE

To determine if blastocyst euploidy rates differ by embryo morphology or day of biopsy.

METHODS

We performed a retrospective analysis of euploidy rates based on patient age, overall embryo morphology grade (good, fair, or poor), and day of biopsy (days 5, 6, or 7) for blastocysts undergoing preimplantation genetic testing for aneuploidy (PGT-A). Our primary analysis included 904 embryos from oocytes age 33-39 years at retrieval.

RESULTS

In our primary analysis, euploidy rates were higher for good quality embryos than poor (64% vs. 48%, p < 0.01) and for fair quality embryos than poor (61% vs. 48%, p < 0.01). There was no significant difference in the euploidy rate between good and fair quality embryos (64% vs. 61%, p = 0.56). Embryos biopsied on day 5 were more likely to be euploid than embryos biopsied on day 6 (59% vs. 50%, p < 0.01) or day 7 (59% vs. 37%, p < 0.01). There was no significant difference in the euploidy rate between day 6 and day 7 embryos (50% vs. 37%, p = 0.07).

CONCLUSION

PGT-A may be more useful in cycles where a lower euploidy rate is expected based on age at oocyte retrieval, embryo morphology, and day of biopsy. There may be little benefit to biopsy of embryos with a high euploidy rate. Young patients with one or more good quality day 5 embryos may benefit from a "transfer the best fresh and biopsy the rest" strategy.

Do patient factors influence embryologists' decisions to freeze borderline blastocysts?

RESEARCH QUESTION

To investigate whether patient factors influence the decision to freeze a blastocyst with low implantation potential.

DESIGN

This experimental study assessed 170 practicing embryologists from a variety of countries who were recruited via an online survey. Participants were currently practicing embryologists, who grade blastocysts as part of this role. The survey presented decision-making 'vignettes' to participants. These included specific patient information, as well as an image of an expanded blastocyst that was of borderline quality for inner cell mass and trophectoderm, for which the embryologist selected whether or not to freeze. High/low maternal age, the presence/absence of other top quality blastocysts, and the presence/absence of previously unsuccessful IVF cycles were systematically varied within the patient information in a 2 × 2 × 2 design. Participants reported how likely they would be to freeze a particular blastocyst on a scale of 1 (Extremely Unlikely) to 7 (Extremely Likely), and whether or not they would ultimately freeze each blastocyst (Yes or No).

RESULTS

Lower maternal age, no other high-quality blastocysts within the cohort, and multiple unsuccessful IVF cycles were associated with greater likelihood of recommending to freeze (P < .001). Furthermore, significant interactions among all three patient factors were noted.

CONCLUSION

This study provides evidence suggesting that when faced with an uncertain blastocyst, factors pertaining to the patient (maternal age, the presence/absence of other top quality blastocysts, and the presence/absence of previously unsuccessful IVF cycles) influence the decision to freeze.

Time of morulation and trophectoderm quality are predictors of a live birth after euploid blastocyst transfer: a multicenter study

OBJECTIVE

To investigate whether the morphodynamic characterization of a euploid blastocyst's development allows a higher prediction of a live birth after single-embryo-transfer (SET).

DESIGN

Observational cohort study conducted in two phases: training and validation.

SETTING

Private in vitro fertilization centers.

PATIENT(S)

Euploid blastocysts: 511 and 319 first vitrified-warmed SETs from 868 and 546 patients undergoing preimplantation genetic testing for aneuploidies (PGT-A) in the training and validation phase, respectively.

INTERVENTION(S)

Data collected from time of polar body extrusion to time of starting blastulation, and trophectoderm and inner-cell-mass static morphology in all embryos cultured in a specific time-lapse incubator with a continuous medium. Logistic regressions conducted to outline the variables showing a statistically significant association with live birth. In the validation phase, these variables were tested in an independent data set.

MAIN OUTCOME MEASURE(S)

Live births per SET.

RESULT(S)

The average live birth rate (LBR) in the training set was 40% (N = 207/511). Only time of morulation (tM) and trophectoderm quality were outlined as putative predictors of live birth at two IVF centers. In the validation set, the euploid blastocysts characterized by tM <80 hours and high-quality trophectoderm resulted in a LBR of 55.2% (n = 37/67), while those with tM ≥ 80 hours and a low-quality trophectoderm resulted in a LBR of 25.5% (N = 13/51).

CONCLUSION(S)

Time of morulation and trophectoderm quality are better predictors of a euploid blastocyst's reproductive competence. Our evidence was reproducible across different centers under specific culture conditions. These data support the crucial role of morulation for embryo development, a stage that involves massive morphologic, cellular, and molecular changes and deserves more investigation.