Differences in Morphokinetic Parameters and Incidence of Multinucleations in Human Embryos of Genetically Normal, Abnormal and Euploid Embryos Leading to Clinical Pregnancy

The selection of the best embryo for embryo transfer (ET) is one of the most important steps in IVF (in vitro fertilisation) treatment. Preimplantation genetic testing (PGT) is an invasive method that can greatly facilitate the decision about the best embryo. An alternative way to select the embryo with the greatest implantation potential is by cultivation in a time-lapse system, which can offer several predictive factors. Non-invasive time-lapse monitoring can be used to select quality embryos with high implantation potential under stable culture conditions. The embryo for ET can then be selected based on the determined morphokinetic parameters and morphological features, which according to our results predict a higher implantation potential. This study included a total of 1027 morphologically high-quality embryos (552 normal and 475 abnormal PGT-tested embryos) from 296 patients (01/2016–06/2021). All embryos were cultivated in a time-lapse incubator and PGT biopsy of trophectoderm cells on D5 or D6 was performed. Significant differences were found in the morphological parameters cc2, t5 and tSB and the occurrence of multinucleations in the stage of two-cell and four-cell embryos between the group of genetically normal embryos and abnormal embryos. At the same time, significant differences in the morphological parameters cc2, t5 and tSB and the occurrence of multinucleations in the two-cell and four-cell embryo stage were found between the group of genetically normal embryos that led to clinical pregnancy after ET and the group of abnormal embryos. From the morphokinetic data found in the PGT-A group of normal embryos leading to clinical pregnancy, time intervals were determined based on statistical analysis, which should predict embryos with high implantation potential. Out of a total of 218 euploid embryos, which were transferred into the uterus after thawing (single frozen embryo transfer), clinical pregnancy was confirmed in 119 embryos (54.6%). Our results show that according to the morphokinetic parameters (cc2, t5, tSB) and the occurrence of multinucleations during the first two cell divisions, the best euploid embryo for ET can be selected with high probability.

Higher preconceptional maternal body mass index is associated with faster early preimplantation embryonic development: the Rotterdam periconception cohort

Background Overweight and obesity affect millions of people globally, which has also serious implications for reproduction. For example, treatment outcomes after in vitro fertilisation (IVF) are worse in women with a high body mass index (BMI). However, the impact of maternal BMI on embryo quality is inconclusive. Our main aim is to study associations between preconceptional maternal BMI and morphokinetic parameters of preimplantation embryos and predicted implantation potential. In addition, associations with clinical IVF outcomes are investigated. Methods From a tertiary hospital, 268 women undergoing IVF or IVF with intracytoplasmic sperm injection (ICSI) were included; 143 normal weight, 79 overweight and 46 obese women. The embryos of these women were cultured in the EmbryoScope, a time-lapse incubator. The morphokinetic parameters of preimplantation embryos and predicted implantation potential, assessed by the KIDScore algorithm were longitudinally evaluated as primary and secondary outcomes, respectively. The tertiary outcomes included clinical outcomes, i.e., fertilization, implantation and live birth rate. Results After adjustment for patient- and treatment-related factors, we demonstrated in 938 embryos that maternal BMI is negatively associated with the moment of pronuclear appearance (βtPNa -0.070 h (95%CI -0.139, -0.001), p = 0.048), pronuclear fading (βtPNf -0.091 h (95%CI -0.180, -0.003), p = 0.043 and the first cell cleavage (βt2 -0.111 h (95%CI -0.205, -0.016), p = 0.022). Maternal BMI was not significantly associated with the KIDScore and tertiary clinical treatment outcomes. In embryos from couples with female or combined factor subfertility, the impact of maternal BMI was even larger (βtPNf -0.170 h (95%CI -0.293, -0.047), p = 0.007; βt2 -0.199 h (95%CI -0.330, -0.067), p = 0.003). Additionally, a detrimental impact of BMI per point increase was observed on the KIDScore (β -0.073 (se 0.028), p = 0.010). Conclusions Higher maternal BMI is associated with faster early preimplantation development. In couples with female or combined factor subfertility, a higher BMI is associated with a lower implantation potential as predicted by the KIDScore. Likely due to power issues, we did not observe an impact on clinical treatment outcomes. However, an effect of faster preimplantation development on post-implantation development is conceivable, especially since the impact of maternal BMI on pregnancy outcomes has been widely demonstrated.

Morphokinetics of Porcine and Bovine Embryos and Anomalies in Their Development

The objective of this study was to evaluate the kinetics of bovine and porcine embryos that failed or developed to the blastocyst stage and anomalies in cleavage using a time-lapse monitoring system. The timing of early cleavages and their duration were similar for bovine and porcine embryos that developed to the blastocyst stage. There were differences in the time of first and second cell division of the bovine embryos that developed and those that did not develop to blastocyst stage (P=0.004 and P=0.002), respectively. Similarly, in case of porcine embryos such difference was observed only in the time of first cleavage (P=0.0001). Direct cleavage from 1-cell to 3 cells occurred in 13.47% and to more than 3 cells in 3.37% of porcine embryos whereas to 3-cells occurred in 4.23% of bovine embryos. The reverse cleavage was observed in 4.33% of porcine and 8.45% of bovine embryos. Conclusion: Our study showed: 1) The similarities in timing and duration of early cleavages of bovine and porcine embryos during development to the blastocyst stage, 2) Differences in morphokinetic parameters between bovine and porcine embryos developing or non-developing to the blastocyst, 3) Anomalies in cleaving of in vitro developing bovine and porcine embryos.

P-203 Applying artificial intelligence for ploidy prediction: The concentration of IL-6 in spent culture medium, blastocyst morphological grade and embryo morphokinetics as variables under consideration

Study question Would it be possible to predict embryo ploidy by taking into account conventional morphological and morphokinetic parameters together with IL-6 concentration in spent culture medium? Summary answer Our artificial neural network (ANN) trained with blastocyst morphology, embryo morphokinetics and IL-6 concentration distinguished between euploid/aneuploid embryos in 65% of the testing dataset. What is known already The analysis of spent embryo culture media represents the protein and metabolic state of the embryo and could be a non-invasive method of obtaining information about embryo quality. The impact of the presence/absence of several proteins in embryo culture samples over clinical results has been widely studied. The IL-6 is one of the most mentioned protein for its effect on embryo development, implantation and likelihood of achieving a live birth. In this initial attempt, we examined the predictive value for euploidy of a model that took into account the concentration of IL-6 in the spent culture medium. Study design, size, duration This prospective study included 319 embryos with PGT-A results. Out of the total, 127 were euploid and 192 aneuploid embryos. Concentration of IL-6 in spent embryo culture media (collected on the day of trophectoderm biopsy-fifth/sixth day of development), morphokinetic parameters (division time to 2 cells-t2; to 3 cells-t3, to 4 cells-t4; to 5 cells-t5 and time of blastocyst formation-tB) and blastocyst morphological grade (according to ASEBIR criteria) were considered to predict the embryo ploidy. Participants/materials, setting, methods Embryos were cultured in EmbryoScope. The chromosome analysis was performed using next-generation sequence technology. The concentration of IL-6 was measured in 20µL of spent embryo culture media with ELISA kits. Morphokinetic parameters were automatically annotated and the blastocyst morphology was evaluated by senior embryologists based on blastocele expansion, inner cell mass and trophectoderm quality. All the embryos were divided into 70% for training, 15% for validating and 15% for testing our ANN model with MatLab®. Main results and the role of chance The general description for the euploid embryo population was the following: 2% of the embryos were graded as A, 71% were graded as B and 28% were graded as C; the means and standard deviations were 25.32±2.97 hours (h) for t2, 35.33±5.15h for t3, 37.30±5.43h for t4, 48.24±6.62h for t5 and 103.93±12.8h for tB; and the average of IL-6 concentration was 1.51±0.70 pg/ml. The general description for the aneuploid embryo population was the following: 1% of the embryos were graded as A, 48% were graded as B and 51% were graded as C; the means and standard deviations were 26.13±3.51h for t2, 36.70±4.29h for t3, 38.20±4.24h for t4, 49.86±6.89h for t5 and 107.10±8.29h for tB; and the average of IL-6 concentration was 1.47±0.71 pg/ml. Our ANN model showed a higher general success rate as we increased the variables considered in the final prediction of euploid embryos. The accuracy, sensitivity and specificity for the testing dataset were: 0.60, 0.12 and 0.87 with morphokinetic parameters; 0.63, 0.24 and 0.93 with morphokinetics and IL-6 concentration; and 0.65, 0.16 and 0.96 with morphokinetics, IL-6 concentration and blastocyst morphological grade. Limitations, reasons for caution The low sensitivity and high specificity achieved in our models indicated that they were more capable of detecting aneuploid than euploid embryos. As this was a preliminary study, the small number of embryos included in the test (n = 48) was also a limitation. Wider implications of the findings The results showed that our model tended to classify the embryos as aneuploid. More euploid embryos would be necessary to train our model and achieve better results in the prediction of chromosomally normal embryos. Further studies with large number of embryos and additional variables could improve the non-invasive ploidy prediction. Trial registration number not applicable

P–278 The embryo score provided by the KIDScoreD5 is correlated with implantation rate and clinical outcomes in fresh transfer

Study question Can the algorithm used by EmbryoScopePlus software predict implantation and clinical pregnancy in women of different age groups on fresh transfer? Summary answer The embryo score generated by KIDScoreD5 is highly related to the rates of implantation and clinical pregnancy in fresh transfers in women of different age. What is known already Artificial Intelligence algorithms use statistics to find patterns in large amounts of data and describe a non-biased approach to multiparameter analysis. Several algorithms have been described, but none has been adopted for universal use. KIDScoreD5 is the algorithm included in the EmbryoScopePlus system and classifies embryos according to the cleavage times and morphology of the blastocyst. Version 3, more current, includes the annotations of the number of pronuclei, the time of division for 2, 3, 4 and 5 cells, time to start of blastulation, and morphology of the Internal Cell Mass and trophectoderm. Study design, size, duration Retrospective study evaluated 86 embryos from January to December 2019 at the Reproferty clinic, grown at EmbryoScopePlus and transferred fresh on the fifth day of embryo development. The morphological and morphokinetic parameters were automatically evaluated by the software and in case of any mistake, they were manually corrected. The embryos were evaluated by KIDScoreD5 v3 in different scores from 0.0 to 9.9 and divided into 4 groups (0.0–2.5; 2.6–5.0; 5.1–7.5; 7.6 –9.9). Participants/materials, setting, methods The inclusion criterion was transfer of a single embryo with 1 gestational sac and positive FHB and transfer of two embryos with 2 gestational sac and positive FHB. Patients with progesterone on the trigger day ≥ 1.5ng/mL and/or with endometrium ≤7mm were excluded. The implantation and clinical pregnancy rates were calculated according to age group, G1: ≤35 years; G2: between 36 and 39 years old; G3: ≥40 years, within the embryo classification. Main results and the role of chance For patients in group 1 (n = 31 embryos), 33.4% of the embryos were classified between 2.6–5.0; 69.20% of embryos with scores between 5.1–7.5 and 57.10% of embryos with scores between 7.6–9.9, with 100% of embryos that implanted, regardless of classification, resulting in clinical pregnancy . For group 2 (n = 35 embryos), they only showed an implantation rate for embryos where the scores were 5.1–7.5 (33.4%) and 7.6 - 9.9 (71.4%) , with 100% being the clinical pregnancy rate in these groups. For patients in group 3 (n = 24 embryos), we also observed implantation only in groups of embryos with a score of 5.1–7.5 (37.5%) and 7.6–9.9 (18.5%) , but the clinical pregnancy rate was lower when compared to the other age groups of the patients, with 33.5% for embryos having a score between 5.1–7.5 and 50% for the group 7.6–9.9. Regarding the average score given by the classification of KIDScore Day 5 v. 3 for embryos that implanted, for patients aged 35 years or less, the average was 6.92; for patients between 36 and 39 years old, the average was 8.06 and for patients aged 40 years or older, the average was 7.32. Limitations, reasons for caution This project is limited because it is a retrospective study and evaluated embryos from a single breeding center. Multicenter and prospective studies are necessary to validate the universal use of the KIDScoreD5 v3 algorithm in time-lapse incubators. Wider implications of the findings: The study showed the ability of KIDScoreD5 v3 to assist the embryologist in deciding which embryo to transfer fresh, according to the patient’s age, in addition to the software being effective in automatic annotation of morphological and morphokinetic parameters. Validating an algorithm universally will improve embryonic selection. Trial registration number Not applicable

P–233 The spatial arrangement of blastomeres and time of cavitation forming as predictors of blastocyst quality

Study question Does the spatial arrangement of blastomeres and the start of blastulation affect blastocyst quality? Summary answer Better blastocyst quality is associated with the spatial arrangement of the embryo and the shorter time frame of blastulation (cavitation). What is known already The ability to select the human embryo with the highest implantation potential remains one of the greatest challenges in the management of In Vitro Fertilization patients. Several publications have proposed that additional morphological evaluations of blastomere arrangement and the dynamics of late-stage embryonic divisions might be a useful non-invasive way for embryo selection. In the last decade, the introduction of time-lapse technology enables continuous monitoring of embryo development, which leads to better outcomes than a selection based on the traditional morphology assessment. Study design, size, duration The spatial arrangement was defined as tetrahedrally if the cleavage planes were perpendicularly orientated, while embryos with rather parallelly orientated cleavage axes were considered as non-tetrahedral embryos. The injection time of ICSI was designated as “time zero” (t0), and EmbryoViewer software was used to calculate the time duration between injection and start of blastulation (cavitation). Obtained results were later correlated with the embryo’s capability to form a blastocyst as well as with blastocyst quality. Participants/materials, setting, methods A total of 195 oocytes from 40 patients undergoing the antagonist cycle for ICSI treatment were evaluated. All blastocysts were cultured in Embryoscope™ according to the manufacturer’s specifications (Vitrolife, Sweden). The Gardner and Schoolcraft scoring system was used to describe blastocyst quality. Statistical analyses were performed using IBM SPSS version 24. Data were reported as median and range. Differences between groups were tested using the Mann-Whitney U test. Statistical significance was defined as p < 0.05. Main results and the role of chance Obtained data showed that 83.6% (61/73) of embryos with tetrahedral arrangement formed blastocysts compared to 42.4% (50/116) of embryos with the non-tetrahedral arrangement (p < 0,001). Moreover, tetrahedral embryos more frequently formed good quality blastocyst compare to the non-tetrahedral [59% (36/61) vs 18 (9/50)% respectively; p < 0,001]. In addition, we found that good quality blastocyst had a significantly shorter time frame between injection and blastulation start, compared with blastocysts which did not reach good quality [95.00h (84–118) vs 102h (77–121) respectively; p = 0,006]. Limitations, reasons for caution The limitation of the present study was that due to the double-embryo transfer correlation between those morphokinetic parameters and pregnancy rate can not be calculated. Further research should link these morphokinetic parameters with pregnancy rate and live birth rate as well. Wider implications of the findings: The potential of our findings is considerable, especially for countries with strict Embryo Law Regulation. Obtained results might be highly useful for selecting embryos with high implantation potential. In addition, the present work illustrates the possibility of additional information that can potentially be incorporated into an embryo classification model. Trial registration number Not applicable

P–198 Higher rate of direct uneven cleavage (DUC) embryos in women exhibiting high ovarian response

Study question Does high ovarian response to controlled ovarian stimulation (COS) have a negative effect on oocyte quality? Summary answer High ovarian response is associated with reduced oocyte quality manifested as higher fraction of immature oocytes and higher rate of direct uneven cleavage (DUC) embryos. What is known already The literature regarding the effect of ovarian hyperstimulation on oocyte quality is limited and controversial. Results from several studies suggest that hyper response to controlled ovarian stimulation has a detrimental effect on oocyte and embryo quality, while others failed to confirm the existence of a direct toxic effect on oocyte and embryo quality. The association between temporal embryonal milestones and implantation rate has been previously demonstrated ,offering an additive tool by which oocyte quality, represented by embryo dynamics, can be evaluated. None of the aforementioned studies, however, used time lapse monitoring (TLM) system to evaluate oocyte and embryo quality. Study design, size, duration This study included a retrospective assessment of morphokinetic parameters performed by TLM from three university affiliated medical centers between January 2014 and December 2019. The developmental process and kinetics of 1863 embryos obtained from the study group, referred as the “ high ovarian response” (HOR) group, was compared to 4907 embryos from the control group - the “normal ovarian response” (NOR) group. Participants/materials, setting, methods The study included patients younger than 38 years who underwent COS with consecutive aspiration of either more than 15 oocytes (the HOR group) or 6–15 oocytes (the NOR group). A comparison was made between the groups regarding morphokinetic parameters, including the rate of embryos manifesting direct uneven cleavage (DUC) at first cleavage (DUC–1), as well as implantation and pregnancy rates. Logistic regression was conducted to assess the association between patients’ characteristics and implantation rate. Main results and the role of chance Oocyte maturation rate was significantly lower, and the DUC–1 embryos rate was significantly higher in the high ovarian response group compared to the normal ovarian response group (56.5% Vs 90.0%, p < 0.001 and 16.2% Vs 12.0%, p = <0.001; respectively). Following the exclusion of DUC–1 embryos, embryos from the HOR and the NOR groups reached the consecutive morphokinetic milestones at a similar rate and demonstrated similar implantation and clinical pregnancy rates. In a multivariate analysis preformed, only maternal age was found to be predictive for implantation. Limitations, reasons for caution The groups were not homogenous in their basic characteristics. Important information regarding the maximal dose of GT obtained, previous IVF response and ovarian reserve testing was lacking Wider implications of the findings: Higher oocyte quantity might have an effect on oocyte quality manifested as higher fraction of incompetent oocytes and higher rate of DUC–1 embryos. Once beyond the preliminary developmental stages, embryos from both groups reach the morphokinetic milestones at a similar rate and display similar implantation and pregnancy rates. Trial registration number Not applicable

P–203 Applying artificial intelligence for ploidy prediction: The concentration of IL–6 in spent culture medium, blastocyst morphological grade and embryo morphokinetics as variables under consideration

Study question Would it be possible to predict embryo ploidy by taking into account conventional morphological and morphokinetic parameters together with IL–6 concentration in spent culture medium? Summary answer Our artificial neural network (ANN) trained with blastocyst morphology, embryo morphokinetics and IL–6 concentration distinguished between euploid/aneuploid embryos in 65% of the testing dataset. What is known already The analysis of spent embryo culture media represents the protein and metabolic state of the embryo and could be a non-invasive method of obtaining information about embryo quality. The impact of the presence/absence of several proteins in embryo culture samples over clinical results has been widely studied. The IL–6 is one of the most mentioned protein for its effect on embryo development, implantation and likelihood of achieving a live birth. In this initial attempt, we examined the predictive value for euploidy of a model that took into account the concentration of IL–6 in the spent culture medium. Study design, size, duration This prospective study included 319 embryos with PGT-A results. Out of the total, 127 were euploid and 192 aneuploid embryos. Concentration of IL–6 in spent embryo culture media (collected on the day of trophectoderm biopsy-fifth/sixth day of development), morphokinetic parameters (division time to 2 cells-t2; to 3 cells-t3, to 4 cells-t4; to 5 cells-t5 and time of blastocyst formation-tB) and blastocyst morphological grade (according to ASEBIR criteria) were considered to predict the embryo ploidy. Participants/materials, setting, methods Embryos were cultured in EmbryoScope. The chromosome analysis was performed using next-generation sequence technology. The concentration of IL–6 was measured in 20µL of spent embryo culture media with ELISA kits. Morphokinetic parameters were automatically annotated and the blastocyst morphology was evaluated by senior embryologists based on blastocele expansion, inner cell mass and trophectoderm quality. All the embryos were divided into 70% for training, 15% for validating and 15% for testing our ANN model with MatLab®. Main results and the role of chance The general description for the euploid embryo population was the following: 2% of the embryos were graded as A, 71% were graded as B and 28% were graded as C; the means and standard deviations were 25.32±2.97 hours (h) for t2, 35.33±5.15h for t3, 37.30±5.43h for t4, 48.24±6.62h for t5 and 103.93±12.8h for tB; and the average of IL–6 concentration was 1.51±0.70 pg/ml. The general description for the aneuploid embryo population was the following: 1% of the embryos were graded as A, 48% were graded as B and 51% were graded as C; the means and standard deviations were 26.13±3.51h for t2, 36.70±4.29h for t3, 38.20±4.24h for t4, 49.86±6.89h for t5 and 107.10±8.29h for tB; and the average of IL–6 concentration was 1.47±0.71 pg/ml. Our ANN model showed a higher general success rate as we increased the variables considered in the final prediction of euploid embryos. The accuracy, sensitivity and specificity for the testing dataset were: 0.60, 0.12 and 0.87 with morphokinetic parameters; 0.63, 0.24 and 0.93 with morphokinetics and IL–6 concentration; and 0.65, 0.16 and 0.96 with morphokinetics, IL–6 concentration and blastocyst morphological grade. Limitations, reasons for caution The low sensitivity and high specificity achieved in our models indicated that they were more capable of detecting aneuploid than euploid embryos. As this was a preliminary study, the small number of embryos included in the test (n = 48) was also a limitation. Wider implications of the findings: The results showed that our model tended to classify the embryos as aneuploid. More euploid embryos would be necessary to train our model and achieve better results in the prediction of chromosomally normal embryos. Further studies with large number of embryos and additional variables could improve the non-invasive ploidy prediction. Trial registration number Not applicable