Search

Background: The change of morphokinetic pattern in aneuploid embryos will facilitate the non-invasive selection of euploid embryos. In this study, we investigated the impact of different chromosomal abnormalities on the morphokinetic patterns of embryonic development. Methods: Our cohort includes 939 time-lapse preimplantation genetic testing cycles performed between January 2019 and July 2022 at a single academic fertility center, with a total of 2876 biopsied blastocysts. Intracytoplasmic sperm injection, blastocyst culture, trophectoderm biopsy, time-lapse monitoring, and next-generation sequencing were performed. Results: After adjusting for patient- and cycle-related factors, six morphokinetic parameters (t5, P = 0.006; t8, P = 0.048; tSB, P

During the in vitro fertilization and embryo transfer process, some expectant mothers may not have good embryos to choose from before the embryo transfer. Recommendations for this condition are currently unclear, and relevant clinical and neonatal outcomes are still lacking. This study analyzed the outcomes of poor-quality embryo transfers, including fetal outcomes, in the fresh cycle and frozen–thawed embryo transfer cycle. Embryos were also analyzed for abnormalities during the cleavage stage. The results indicate that in the absence of good embryos, clinicians and embryologists could advise expectant mothers to continue culturing the embryos to the blastocyst stage and undergo transfer if blastocysts are formed. This finding can also be used as a reference for many expectant mothers with frozen embryos that have not yet been thawed.

Objective: To measure the impact of maternal body mass index (BMI) on the morphokinetics of embryo development as monitored by a time-lapse system. Design: A retrospective chart review of in vitro fertilization (IVF) cycles from September 2016 to January 2019. Setting: Academic IVF practice. Patient(s): Patients

One of the most common treatments for infertile couples is In Vitro Fertilization (IVF). It consists of controlled ovarian hyperstimulation, followed by ovum pickup, fertilization, and embryo culture for 2–6 days under controlled environmental conditions, leading to intrauterine transfer or freezing of embryos identified as having a good implantation potential by embryologists. To allow continuous monitoring of embryo development, Time-lapse imaging incubators (TLI) were first released in the IVF market around 2010. This time-lapse technology provides a dynamic overview of embryonic in vitro development by taking photographs of each embryo at regular intervals throughout its development. TLI appears to be the most promising solution to improve embryo quality assessment methods, and subsequently the clinical efficiency of IVF. In particular, the unprecedented high volume of high-quality images produced by TLI systems has already been leveraged using modern Artificial Intelligence (AI) methods, like deep learning (DL).An important limitation to the development of AI-based solutions for IVF is the absence of a public reference dataset to train and evaluate deep learning (DL) models. In this work, we describe a fully annotated dataset of 704 TLI videos of developing embryos with all 7 focal planes available, for a total of 2,4M images. Of note, we propose highly detailed annotations with 16 different development phases, including early cell division phases, but also late cell divisions, phases after morulation, and very early phases, which have never been used before. This is the first public dataset that will allow the community to evaluate morphokinetic models and the first step towards deep learning-powered IVF. We postulate that this dataset will help improve the overall performance of DL approaches on time-lapse videos of embryo development, ultimately benefiting infertile patients with improved clinical success rates.

Research Question: Is there a relationship between the pronuclear axis and the first cleavage plane formation in human pronuclear-stage embryos, and what are the effects on ploidy and clinical pregnancy rates?, Design: Transferred embryos were followed up until their prognoses. A total of 762 embryos formed two cells and reached the blastocyst stage after normal fertilization in a time-lapse incubator. Embryos were classified into three groups: group A: embryos in which the first plane of division was formed parallel to the axis of the pronucleus; group B: embryos in which cases of oblique formation were observed; and group C: embryos in which cases of perpendicular formation were observed., Results: The euploidy rate was significantly higher in groups A and B than those in group C (P < 0.01), whereas the aneuploidy rate was significantly higher in group C (P < 0.01) than in groups A and B. No differences were found between the three groups in frequency of positive HCG-based pregnancy tests, frequency of clinical pregnancies, miscarriage rates or delivery rates., Conclusions: The formation pattern of the first plane of division relative to the pronuclear axis was a predictor of embryonic ploidy, with a reduced rate of euploidy and a high probability of aneuploidy observed when the first plane of division was perpendicular to the pronuclear axis., (Copyright © 2024 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Do cell numbers and degree of fragmentation in cleavage-stage embryos, assessed manually, correlate with evaluations made by deep learning algorithm model iDAScore v2.0?, Design: Retrospective observational study (n = 5040 embryos; 1786 treatments) conducted at two Swedish assisted reproductive technology centres between 2016 and 2021. Fresh single embryo transfer was carried out on days 2 or 3 after fertilization. Embryo evaluation using iDAScore v2.0 was compared with manual assessment of numbers of cells and grade of fragmentation, analysed by video sequences., Results: Data from embryos transferred on days 2 and 3 showed that having three or fewer cells compared with four or fewer cells on day 2, and six or fewer cells versus seven to eight cells on day 3, correlated significantly with a difference in iDAScore (medians 2.4 versus 4.0 and 2.6 versus 4.6 respectively; both P < 0.001). The iDAScore for 0-10% fragmentation was significantly higher compared with the groups with higher fragmentation (P < 0.001). When combining cell numbers and fragmentation, iDAScore values decreased as fragmentation increased, regardless of cell number. iDAScore discriminated between embryos that resulted in live birth or no live birth (AUC of 0.627 and 0.607), compared with the morphological model (AUC of 0.618 and 0.585) for day 2 and day 3, respectively., Conclusions: The iDAScore v2.0 values correlated significantly with cell numbers and fragmentation scored manually for cleavage-stage embryos on days 2 and 3. iDAScore had some predictive value for live birth, conditional that embryo selection was based on morphology., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Research Question: Can predictive post-warm parameters that support the decision to transfer a warmed blastocyst or to warm another blastocyst be identified in women with multiple frozen-vitrified blastocysts?, Design: Retrospective single-centre observational cohort analysis. A total of 1092 single vitrified-warmed blastocyst transfers (SVBT) with known Gardner score, maternal age and live birth were used to develop live birth prediction models based on logistic regression, including post-warm re-expansion parameters. Time-lapse incubation was used for pre-vitrification and post-warm embryo culture. A dataset of 558 SVBT with the same inclusion criteria was used to validate the model, but with known clinical pregnancy outcome instead of live birth outcome., Results: Three different logistic regression models were developed for predicting live birth based on post-warm blastocyst re-expansion. Different post-warm assessment times indicated that a 2-h post-warm culture period was optimal for live birth prediction (model 1). Adjusting for pre-vitrification Gardner score (model 2) and in combination with maternal age (model 3) further increased predictability (area under the curve [AUC] = 0.623, 0.633, 0.666, respectively). Model validation gave an AUC of 0.617, 0.609 and 0.624, respectively. The false negative rate and true negative rate for model 3 were 2.0 and 10.1 in the development dataset and 3.5 and 8.0 in the validation dataset., Conclusions: Clinical application of a simple model based on 2 h of post-warm re-expansion data, pre-vitrification Gardner score and maternal age can support a standardized approach for deciding if warming another blastocyst may increase the likelihood of live birth in SVBT., (Copyright © 2023 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Do morphokinetic parameters vary between male and female preimplantation embryos?, Design: This was a retrospective cohort study of 175 cycles between March 2018 and June 2021 at two reproductive centres. It included time-lapse data from 92 female and 83 male preimplantation embryos exclusively issued from fresh oocyte donation and undergoing intracytoplasmic sperm injection (ICSI). Only fresh elective single-embryo transfers on day 5 were assessed, and the sex of the embryo was confirmed at birth. The morphokinetic parameters analysed were measured in hours post-insemination (hpi). A two-tailed Student's t-test was used to compare the morphokinetics between embryo sexes and a value of P < 0.05 was considered statistically significant., Results: Following strict inclusion criteria to avoid poor-quality preimplantation embryos, no significant differences were found in morphokinetic parameters when comparing cycles that resulted in female versus male live births for the following: time to pronuclear fading (22.1 ± 2.4 versus 22.4 ± 2.9 hpi; P = 0.52); time to the 2-cell stage (24.6 ± 2.5 versus 25.0 ± 2.5 hpi; P = 0.34); time to the 3-cell stage (35.3 ± 3.3 versus 35.8 ± 3.1 hpi; P = 0.28); time to the 4-cell stage (36.3 ± 3.4 versus 36.9 ± 3.7 hpi; P = 0.20); time to the 5-cell stage (47.9 ± 4.6 versus 48.0 ± 4.8 hpi; P = 0.88); time to the 8-cell stage (54.0 ± 6.5 versus 54.1 ± 6.5 hpi; P = 0.91); time to the start of blastulation (86.3 ± 14.6 versus 85.7 ± 15.5 hpi; P = 0.78); and time to the full blastocyst stage (93.0 ± 16.9 versus 93.2 ± 17.2 hpi; P = 0.94)., Conclusions: There are no significant differences in morphokinetics between male and female preimplantation embryos., (Copyright © 2023 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Can models based on artificial intelligence predict embryonic ploidy status or implantation potential of euploid transferred embryos? Can the addition of clinical features into time-lapse monitoring (TLM) parameters as input data improve their predictive performance?, Design: A single academic fertility centre, retrospective cohort study. A total of 773 high-grade euploid and aneuploid blastocysts from 212 patients undergoing preimplantation genetic testing (PGT) between July 2016 and July 2021 were studied for ploidy prediction. Among them, 170 euploid embryos were single-transferred and included for implantation analysis. Five machine learning models and two types of deep learning networks were used to develop the predictive algorithms. The predictive performance was measured using the area under the receiver operating characteristic curve (AUC), in addition to accuracy, precision, recall and F1 score., Results: The most predictive model for ploidy prediction had an AUC, accuracy, precision, recall and F1 score of 0.70, 0.64, 0.64, 0.50 and 0.56, respectively. The DNN-LSTM model showed the best predictive performance with an AUC of 0.78, accuracy of 0.77, precision of 0.79, recall of 0.86 and F1 score of 0.83. The predictive power was improved after the addition of clinical features for the algorithms in ploidy prediction and implantation prediction., Conclusion: Our findings emphasize that clinical features can largely improve embryo prediction performance, and their combination with TLM parameters is robust to predict high-grade euploid blastocysts. The models for ploidy prediction, however, were not highly predictive, suggesting they cannot replace preimplantation genetic testing currently., (Copyright © 2022 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: What is the reliability of Geri® Assess 2.0 software time-lapse technology for annotating kinetic events and identifying abnormal phenotypes in preimplantation human embryos?, Design: Embryos were annotated using Assess 2.0 for the appearance and fading of pronuclei, and for progression to the 2-, 3-, 4-, 5- and 6-cell stages and to three blastocyst stages. Identification of reverse cleavage and direct cleavage phenotypes was also recorded. Manual annotation was undertaken after these events in a blinded fashion. Embryo scores were compared between Assess 2.0 and manual annotation., Results: A total of 513 oocytes from 34 women were included. Detection rates for Assess 2.0 versus manual annotation among the 10 kinetic events and including direct cleavage and reverse cleavage ranged between 0% and 94.4%. The percentage of discordant pairs was significantly different for all 12 events analysed (P-value range 0.036 to <0.0001). The sensitivity of Assess 2.0 ranged from 68.2% to 94.4% and specificity ranged from 63.8% to 97.3%. Assess 2.0 called for verification by the embryologist for at least one event in 55.2% of oocytes assessed. Of the 297 embryos scored by manual annotation, Assess 2.0 assigned the same score for only 125 (42.1%), although after manual corrections, concordance with manual annotation scores was raised to 66.0%., Conclusions: The results reveal striking differences between Assess 2.0 and manual annotation for kinetic annotations. Failure of Assess 2.0 to detect direct cleavage events and the low detection rate of reverse cleavage are further limitations. These collective findings highlight the importance of validating time-lapse annotation software before clinical implementation. Manual verification of Assess 2.0 outputs remains essential for accurate data interpretation., (Copyright © 2022 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Can KIDScoreD5 predict which blastocysts have the highest potential for achieving pregnancy?, Design: A retrospective cohort study of 670 single fresh or frozen (FET) embryo transfer cycles was conducted between May 2019 and June 2021 at the Ottawa Fertility Centre, Canada. Blastocysts obtained from stimulated eligible cycles and cultured in a time-lapse incubator were selected for transfer or cryopreservation based on Gardner morphological scoring. Implantation and viable pregnancy rates were analysed retrospectively using KIDScoreD5 and Gardner scores associated with the transferred embryos. The predictive power of the KIDScoreD5 and Gardner assessment was evaluated using the average area under the curve (AUC) of the receiver operating characteristic curve., Results: KIDScoreD5 was positively correlated with implantation (r = 0.96, P = 0.002) and viable pregnancy (r = 0.96, P  = 0.0001) rates. In fresh embryo transfer cycles, the AUC for implantation rate was significantly higher for KIDScoreD5 compared with Gardner scoring (0.70 versus 0.63, P  = 0.03). For FET, significantly higher AUC were calculated for KIDScoreD5 than for Gardner scoring, for both implantation (0.64 versus 0.54, P  = 0.002) and viable pregnancy (0.63 versus 0.53, P  = 0.002) rates. When the ranking of cryopreserved embryos was based on KIDScoreD5, 46.2% of the FET cycles had at least one unused sibling embryo with a better KIDScoreD5 than the one selected for FET based on Gardner assessment., Conclusions: KIDScoreD5 predicts implantation and viable pregnancy rates of blastocysts better than Gardner morphological assessment in single fresh or cryopreserved embryo transfer cycles., (Copyright © 2022. Published by Elsevier Ltd.)

Aims: We aimed to investigate the effect of sperm miR-34c on early human embryonic development kinetics and clinical outcomes of in vitro fertilization (IVF) patients., Materials and Methods: After oocyte insemination, residual sperm specimens were collected from 58 patients undergoing IVF. miR-34c expression levels in sperm, oocytes, zygotes, and embryos/blastocysts were detected with qRT-PCR, and embryonic development kinetics were observed using time-lapse technology. To confirm the role of miR-34c in regulation of early embryonic development, miR-34c siRNA was injected into zygotes obtained from in vitro-matured oocytes. A ROC curve was used to determine the cutoff value. Comparisons of embryonic development kinetics and clinical outcomes were performed according to the cutoff value., Key Findings: The miR-34c expression level was highest in 3PN zygotes, but was not expressed in human oocytes. In the miR-34c siRNA group, embryonic development kinetic parameters t2, t3, t4, and t5 were significantly prolonged, but the cleavage rate and high-quality embryo rate were lower than in the control group. The levels of sperm miR-34c were negatively correlated with t5 and positively correlated with rates of blastocyst formation, high-quality blastocysts, and pregnancy. The miR-34c levels and the blastocyst formation rate were higher in the pregnancy group (p < 0.05). Logistic regression analysis showed that sperm miR-34c level was significantly correlated with pregnancy (OR: 5.056, 95% CI: 1.560-16.384; p = 0.007)., Significance: The sperm miR-34c expression level is associated with embryonic development kinetics and clinical outcomes. Thus, miR-34c expression is beneficial to embryonic development and may be used as an indicator of IVF outcomes., Competing Interests: Declaration of competing interest The authors have no conflict of interest to report., (Copyright © 2020. Published by Elsevier Inc.)

Vertebrate head morphogenesis involves carefully-orchestrated tissue growth and cell movements of the mesoderm and neural crest to form the distinct craniofacial pattern. To better understand structural birth defects, it is important that we characterize the dynamics of these processes and learn how they rely on each other. Here we examine this question during chick head morphogenesis using time-lapse imaging, computational modeling, and experiments. We find that head mesodermal cells in culture move in random directions as individuals and move faster in the presence of neural crest cells. In vivo, mesodermal cells migrate in a directed manner and maintain neighbor relationships; neural crest cells travel through the mesoderm at a faster speed. The mesoderm grows with a non-uniform spatio-temporal profile determined by BrdU labeling during the period of faster and more-directed neural crest collective migration through this domain. We use computer simulations to probe the robustness of neural crest stream formation by varying the spatio-temporal growth profile of the mesoderm. We follow this with experimental manipulations that either stop mesoderm growth or prevent neural crest migration and observe changes in the non-manipulated cell population, implying a dynamic feedback between tissue growth and neural crest cell signaling to confer robustness to the system. Overall, we present a novel descriptive analysis of mesoderm and neural crest cell dynamics that reveals the coordination and co-dependence of these two cell populations during head morphogenesis., Competing Interests: Declaration of competing interest No competing interests declared., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Research Question: To study the origin and temporal behaviour of cytoplasmic strings spanning the blastocoel (main objective) and their influence on treatment outcome (secondary objective)., Design: This retrospective analysis of prospectively collected data was set up in a university medical centre. Patients who either underwent fresh (n = 95) or vitrified-warmed (n = 55) single blastocyst transfer were included. Time-lapse sequences of in-vitro developed blastocysts were screened for the presence of cytoplasmic strings. Pregnancies in string-positive and string-negative transfers were followed up to live birth., Results: A total of 387 blastocysts were obtained in the fresh cycles of 100 patients, corresponding to a blastocyst formation rate of 62.4%. Cytoplasmic strings were first detected around full stage (108.5 ± 6.4 h) in 170 blastocysts (43.9%). The number of strings varied (range: 1-7) and the duration of visibility was 5.2 ± 3.5 h. The occurrence of cytoplasmic strings was significantly associated with the presence of blastocoelic collapses (P < 0.001) but not with any of the annotated morphokinetic parameters. Live birth and neonatal outcome were the same for both string-positive and string-negative pregnancies. Moreover, collapses did not affect treatment outcome., Conclusion: Time-lapse analysis of cytoplasmic strings at the blastocyst stage revealed that this morphological feature was not a negative predictor as previously reported. Although physiologically normal, at least some of the cytoplasmic strings are an artefact, possibly associated with blastocoelic collapses., (Copyright © 2019 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: How can the kinetics of human blastocyst expansion be used to evaluate an embryo's ploidy identified using preimplantation genetic testing for aneuploidy (PGT-A)?, Design: This was a retrospective observational study of 188 autologous blastocysts from 34 sequential treatment cycles using PGT-A and blastocyst biopsy. Using time-lapse imaging, blastocyst expansion was evaluated using a quantitative standardized expansion assay (qSEA). Trophectoderm cell division was examined in selected, unbiopsied embryos (n = 7) to evaluate the contribution of mitosis to the expansion rate., Results: The averaged euploid blastocyst expansion rate was significantly (52.8%) faster than in aneuploid blastocysts (P = 0.0041). Scatterplots, representing 'expansion maps', revealed that both populations showed a similarly overlapping distribution of blastocyst formation times at 80-140 h from fertilization. Euploidy and aneuploidy were better distinguished in regions of higher and lower expansion, respectively, in expansion maps. Based upon the expansion slopes, rank-ordering of individual embryos within cohorts resulted in more than 90% euploid embryos in the first two ranks in patients less than 35 years of age. Additional detailed time-lapse image analysis provided evidence that rapid expansion was associated with robust, integrative cellular mitosis in trophectoderm cells., Conclusions: The kinetics of human blastocyst expansion are related to an embryo's ploidy. These preliminary observations describe a new quantitative, non-invasive approach to embryo assessment that may be useful to identify single blastocysts for transfer, particularly in younger patient groups. However, this approach may also be useful for euploid embryo selection after PGT-A. The results support the hypothesis that aneuploidy universally impairs general cellular processes, including cell division, in differentiated cells., (Copyright © 2019. Published by Elsevier Ltd.)

Research Question: Can embryo morphokinetic parameters help identify unbalanced embryos in translocation carriers?, Design: This retrospective study was conducted in 67 translocation carriers undergoing 105 preimplantation genetic testing cycles for chromosomal structural rearrangements (PGT-SR) without aneuploidy screening (PGT-A). Using time-lapse imaging analysis, morphokinetic parameters of balanced and unbalanced embryos were compared, as well as the frequency of abnormal cellular events. The performance of a previously published prediction model of aneuploidy was also tested in this population., Results: Significant differences were observed between balanced and unbalanced embryos for some morphokinetic parameters: t5 (P = 0.0067), t9+ (P = 0.0077), cc2 (P = 0.0144), s2 (P = 0.0003) and t5-t2 (P = 0.0028). Also, multinucleation at the two- or four-cell stages, abnormal division and cell exclusion at the morula stage were significantly (all P < 0.05) more frequent in unbalanced than in balanced embryos. None, however, could accurately predict embryo chromosomal status. A previously published morphokinetic prediction model for embryo aneuploidy did not adequately classify balanced and unbalanced embryos., Conclusions: No significant morphokinetic predictor of chromosomal status could be found. Time-lapse should not be used as a diagnostic tool for chromosomal status in translocation carriers., (Copyright © 2018 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Does delayed maturation of aspirated metaphase I (MI) oocytes, completed in vitro, adversely affect early embryo development?, Design: Time-lapse microscopy was used to compare morphokinetic variables between embryos derived from oocytes with delayed maturation after ovarian stimulation and from in-vivo-matured metaphase II (MII) sibling oocytes from the same IVF and intracytoplasmic sperm injection cycle., Results: A total of 1545 injected oocytes in 169 cycles from 149 patients were included. The in-vitro-matured oocytes had lower normal fertilization rates than the MII aspirated oocytes (50.2% versus 68.0%; P < 0.001). Early key developmental events were significantly delayed in the normally fertilized in-vitro-matured compared with in-vivo-matured oocytes (polar body extrusion: 5.4 ± 3 versus 3.9 ± 1.8 h; P < 0.001; pronuclear fading: 27.2 ± 4.7 versus 25.1 ± 4.2 h; P < 0.001, respectively) and synchrony of the second cell cycle was adversely affected. The proportions of embryos with optimal second cell cycle length and second cell cycle were similar but with fewer top-quality embryos, based on an algorithm, for the delayed in-vitro-matured oocytes compared with their in-vivo-matured sibling oocytes (14% versus 29.1%; P < 0.001)., Conclusions: Embryos derived from oocytes that failed to mature in-vivo in standard treatment after ovarian stimulation may show a different morphokinetic profile from their sibling oocytes aspirated at the MII stage after completing maturation in-vivo., (Copyright © 2018 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

During embryonic brain development, groups of particular neuronal cells migrate tangentially to participate in the formation of a laminated structure. Two distinct types of tangential migration in the middle and superficial layers have been reported in the development of the avian optic tectum. Here we show the dynamics of tangential cell movement in superficial layers of developing chick optic tectum. Confocal time-lapse microscopy in organotypic slice cultures and flat-mount cultures revealed that vigorous cell migration continued during E6.5-E13.5, where horizontally elongated superficial cells spread out tangentially. Motile cells exhibited exploratory behavior in reforming the branched leading processes to determine their pathway, and intersected with each other for dispersion. At the tectal peripheral border, the cells retraced or turned around to avoid protruding over the border. The tangentially migrating cells were eventually distributed in the outer stratum griseum et fibrosum superficiale and differentiated into neurons of various morphologies. These results revealed the cellular dynamics for widespread neuronal distribution in the superficial layers of the developing optic tectum, which underline a mode of novel tangential neuronal migration in the developing brain., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Embryo morphology assessment performs relatively poorly in predicting implantation. Embryo aneuploidy screening (PGS) has recently improved, but its clinical value is still debated, and the development of a cheap non-invasive method for the assessment of embryo ploidy status is a highly desirable goal. The growing implementation of time-lapse devices led some teams to test the effectiveness of morphokinetic parameters as predictors of embryo ploidy, with conflicting results. The aim of this study was to conduct a comprehensive review of the literature on the predictive value of morphokinetic parameters for embryo ploidy status. A systematic search on PubMed was conducted using the following key words: time-lapse, morphokinetic, aneuploidy, IVF, preimplantation genetic screening, PGS, chromosomal status. A total of 13 studies were included in the analysis. They were heterogeneous in design, patients, day of embryo biopsy, statistical approach and outcome measures. No single or combined morphokinetic parameter was consistently identified as predictive of embryo ploidy status. In conclusion, the available studies are too heterogeneous for firm conclusions to be drawn on the predictive value of time-lapse analysis for embryo aneuploidy screening. Hence, morphokinetic parameters should not be used yet as a surrogate for PGS to determine embryo ploidy in vitro., (Copyright © 2018 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Perivitelline threads (PVT) are defined as thin filaments that extend across the perivitelline space connecting the zona pellucida with the oolemma or, in some cases, blastomere membrane. This is the first report of PVT in human embryos. Time-lapse imagery from 525 blastocysts with either tested ploidy, known implantation status, or both, were reviewed for the presence of PVT, the cell stage when PVT were first observed, association with fragmentation, ploidy or implantation potential; PVT were observed in most embryos (404/525 [77%]). The euploidy rate was similar in embryos with PVT (61/152 [40%]) and without PVT (17/35 [49%]). Implantation rates were also similar in embryos with PVT (64/259 [25%]) and without PVT (25/90 [28%]). In the embryos in which PVT were observed, 98% (396/404) developed at the two-cell stage. In most embryos (384/404 [95%]), PVT were observed to directly pull fragments from the embryo. Fragmentation occurred significantly less frequently in embryos without PVT compared with PVT (81/121 [67%] versus 388/404 [96%]; P < 0.001). These data suggest an association between PVT and fragmentation. This study is limited in that PVT were not characterized so their nature and origin remain unknown and to be determined in future studies., (Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

The increasing corpus of clinical studies using time-lapse imaging for embryo selection demonstrates considerable variation in study protocols and only limited-sized study cohorts. Outcome measures are based on implantation or clinical pregnancy; some predict blastulation from early cleavage-stage data, and few have evaluated live birth. Erroneously, most studies treat the embryos as independent variables and do not include patient or treatment variables in the statistical analyses. In this study, cohort size was 14,793 patients and 23,762 cycles. The incidence of live birth (n = 973 deliveries) after embryo selection by objective morphokinetic algorithms was compared with conventional embryology selection parameters (n = 6948 deliveries). A 19% increase in the incidence of live birth was observed when morphokinetic data were used to select embryos for the patient cohort aged younger than 38 years (OR 1.19 with 95% CI 1.06 to 1.34) using their own eggs, and an increase of 37% for oocyte recipients aged over 37 years (OR 1.370; 95% Cl 0.763 to 2.450). This is the largest study of the prospective use of time-lapse imaging algorithms in IVF reporting on live birth outcome, although the nature of purely a closed system versus standard incubation could not be assessed., (Copyright © 2017. Published by Elsevier Ltd.)

This retrospective, single site observational study aimed to delineate five abnormal embryonic developmental phenotypes, assessing their prevalence, development potential and suitability for inclusion in embryo selection models for IVF. In total, 15,819 embryos from 4559 treatment cycles cultured in EmbryoScope® incubators between January 2014 and January 2016 were included. Time-lapse images were assessed retrospectively for five abnormal embryo phenotypes: direct cleavage, reverse cleavage, absent cleavage, chaotic cleavage and cell lysis. The prevalence of each abnormal phenotype was assessed. Final embryo disposition, embryo quality and implantation rate were determined and compared with a control embryo cohort. The collective prevalence for the five abnormal phenotypes was 11.4%; chaotic cleavage and direct cleavage together constituted 9.7%. Implantation rates were 17.4%, 0%, 25%, 2.1% and 0% for direct, reverse, absent, chaotic cleavage and cell lysis, respectively. The overall implantation rate for all abnormal embryos with known implantation status was significantly lower compared with the control population (6.9% versus 38.7%, P < 0.0001). The proportion of good quality embryos in each category of abnormal cleavage remained below 25%. Embryos exhibiting an abnormal phenotype may have reduced developmental capability, manifested in both embryo quality and implantation potential, when compared with embryos of normal phenotype., (Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Single embryo culture is suboptimal compared with group culture, but necessary for embryo monitoring, and culture systems should be improved for single embryos. Pronucleate mouse embryos were used to assess the effect of culture conditions on single embryo development. Single culture either before or after compaction reduced cell numbers (112.2 ± 3.1; 110.2 ± 3.5) compared with group culture throughout (127.0 ± 3.4; P < 0.05). Reduction of media volume from 20 µl to 2 µl increased blastocyst cell numbers in single embryos cultured in 5% oxygen (84.4 ± 3.2 versus 97.8 ± 2.8; P < 0.05), but not in 20% oxygen (55.2 ± 2.9 versus 57.1 ± 2.8). Culture in microwell plates for the EmbryoScope and Primo Vision time-lapse systems changed cleavage timings and increased inner cell mass cell number (24.1 ± 1.0; 23.4 ± 1.2) compared with a 2 µl microdrop (18.4 ± 1.0; P < 0.05). Addition of embryo-conditioned media to single embryos increased hatching rate and blastocyst cell number (91.5 ± 4.7 versus 113.1 ± 4.4; P < 0.01). Single culture before or after compaction is therefore detrimental; oxygen, media volume and microwells influence single embryo development; and embryo-conditioned media may substitute for group culture., (Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Irregular cleavage divisions are expected to produce chromosomally deviant embryos. We investigated whether embryos from irregular cleavages could develop into euploid blastocysts, and, if so, whether any evidence existed of a self-correction mechanism of the embryo. We also investigated the role of different dynamic aspects of morula compaction in this process. A total of 791 embryos from 141 patients undergoing pre-implantation genetic screening were retrospectively analysed using a time-lapse imaging system, and multiple cell divisions were evaluated. A total of 276 embryos developed into blastocysts suitable for biopsy and chromosome screening through array-comparative genomic hybridization. As well as testing trophectoderm biopsy specimens for aneuploidy, excluded cells of 18 blastocysts, which developed from partially compacted morulas, were also analysed. Unique data on the developmental fate of embryos with cleavage abnormalities are presented, and a potential mechanism of 'aneuploidy rescue' is postulated through which mosaic embryos may form partially compacted morulas to exclude aneuploid cells. In addition, this process seems to be less efficient in older women. The data obtained also provide further evidence that excluded cells should not be used to infer the cytogenetic status of the embryo., (Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Time-lapse imaging offers new tools to study dynamic processes of development such as blastocyst formation and expansion. This study quantitatively describes expansion in human blastocysts from donated oocytes. Measurements of hourly interval rate of changes in the blastocoel cross-sectional area revealed oscillatory pulses having 2-4 h periodicities. Two types of oscillations were distinguished. An E-Type ('expansion') had positive peak and positive or slightly negative trough interval rate of change values, and these characterized most of the expansion period. A C-type ('contraction') represented an infrequent but notable contraction of the blastocoel with loss of blastocoel fluid. These were reversible within 2-4 h in both groups and followed by further expansion. Therefore, oscillatory pulses are an intrinsic property of the trophectoderm. The zona seems to variably dampen the amplitude of these pulses. Expansion kinetics were compared between blastocysts with known positive (KID+) or negative (KID-) implantation outcomes. Regression analysis suggests that expansion may be relatively restricted in KID- embryos blastulating at relatively later times. These data extend observations in other mammalian systems and may provide information useful for clinical selection algorithms., (Copyright © 2016. Published by Elsevier Ltd.)

Collective cell migration is the coordinated movement of cells, which organize tissues during morphogenesis, repair and some cancers. The motile cell membrane of the advancing front in collective cell migration is termed the Leading Edge. The embryonic development of the vertebrate and Drosophila hearts are both characterized by the coordinated medial migration of a bilateral cluster of mesodermal cells. In Drosophila, the cardioblasts form cohesive bilateral rows that migrate collectively as a unit towards the dorsal midline to form the dorsal vessel. We have characterized the collective cell migration of cardioblasts as an in vivo quantitative model to study the behaviour of the Leading Edge. We investigated whether guidance signalling through Slit and Netrin pathways plays a role in cell migration during heart development. Through time-lapse imaging and quantitative assessment of migratory behaviour of the cardioblasts in loss-of-function mutants, we demonstrate that both Slit and Netrin mediated signals are autonomously and concomitantly required to maximize migration velocity, filopodial and lamellipodial activities. Additionally, we show that another Slit and Netrin receptor, Dscam1, the role of which during heart development was previously unknown, is required for both normal migration of cardioblasts and luminal expansion. Leading edge behaviour analysis revealed a dosage dependent genetic interaction between Slit and Netrin receptors suggesting that downstream signalling through these receptors converge on a common output that increases leading edge activity of the cardioblasts. Finally, we found that guidance signalling maintains the balance between epithelial and mesenchymal characteristics of the migrating cardioblasts., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: To elucidate whether trophoblast expansion and invasion are modulated by androgen signaling in an in vitro co-culture model system with decidualizing endometrial stromal cells (ESCs)., Methods: We employed an in vitro co-culture model of early embryo implantation, consisting of human ESCs (EtsT499 cells) and spheroids generated by extravillous trophoblast (EVT) derived HTR8/Svneo. The ESCs were decidualized with 8-bromo-cAMP (8-br-cAMP) in the presence or absence of dihydrotestosterone (DHT) at various concentrations for 5 days before co-culture with EVT spheroids. Trophoblast expansion was monitored by fluorescent time-lapse imaging microscopy. ESCs motility was visualized by using CellTracker™ Orange CMRA fluorescent probe. Apoptosis of ESCs was detected by CellEvent™ Caspase-3/7 ® green detection reagent. Invasion assays were performed to quantify EVT invasion through a chemotaxis cell membrane., Results: Expansion of EVT spheroids was significantly enhanced by decidualized compared to undifferentiated ESCs. This process was further stimulated if ESCs were first decidualized in the presence of DHT. In contrast to decidualized ESCs, undifferentiated cells actively migrated away from expanding EVT spheroids. Invasiveness of EVT toward decidualized ESCs was significantly attenuated in comparison to undifferentiated ESCs. DHT had no effect on EVT invasion. However, an inhibitor of intercellular gap junction communication significantly enhanced EVT invasion towards decidualized ESCs., Conclusions: These results indicate distinct roles for androgen signaling and gap junction formation in decidual cells in regulating trophoblast expansion and invasion., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Embryos are routinely cultured individually, although this can reduce blastocyst development. Culture in atmospheric (20%) oxygen is also common, despite multiple detrimental effects on embryos. Although frequently occurring together, the consequences of this combination are unknown. Mouse embryos were cultured individually or grouped, under physiological (5%) or atmospheric (20%) oxygen. Embryos were assessed by time-lapse and blastocyst cell allocation. Compared with the control group (5% oxygen group culture), 5-cell cleavage (t5) was delayed in 5% oxygen individual culture and 20% oxygen group culture (59.91 ± 0.23, 60.70 ± 0.29, 63.06 ± 0.32 h post-HCG respectively, P < 0.05). Embryos in 20% oxygen individual culture were delayed earlier (3-cell cleavage), and at t5 cleaved later than embryos in other treatments (66.01 ± 0.40 h, P < 0.001), this delay persisting to blastocyst hatching. Compared with controls, hatching rate and cells per blastocyst were reduced in 5% oxygen single culture and 20% oxygen group culture (134.1 ± 3.4, 104.5 ± 3.2, 73.4 ± 2.2 cells, P < 0.001), and were further reduced in 20% oxygen individual culture (57.0 ± 2.8 cells, P < 0.001), as was percentage inner cell mass. These data indicate combining individual culture and 20% oxygen is detrimental to embryo development., (Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Numerous studies have reported on the potential value of time-lapse variables for prediction of embryo viability. However, these variables have not been evaluated in combination with conventional morphological grading and patient characteristics. The aim of this study was to assess the ability of patient characteristics and embryo morphology together with morphokinetic variables to predict live birth after day 2 transfer. This retrospective analysis included 207 transferred embryos from 199 couples cultured in a time-lapse system up to day 2 of development. Good prediction of live birth or ranking of embryos with respect to live birth potential was achieved with early cleavage combined with fragmentation grade at 43-45 h. These variables were selected as the strongest predictors of live birth, as assessed by stepwise logistic regression, and additional inclusion of morphokinetic variables did not improve the model significantly. Also, neither logistic regression models nor classification tree models with morphokinetic variables were able to achieve equally good prediction of live birth, as measured by AUC on an external data set not used for model development. In conclusion, for fresh day 2 transfers early cleavage in combination with fragmentation grade at 43-45 h should be considered when selecting between good quality embryos., (Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Introduction: Human bite marks are often sustained during sexual, domestic or child abuse. Currently, analysis of these marks involves digital photography techniques along with an expert forensic odontologist opinion. Photographs often focus closely on the bite mark and give little context to the anatomical location of the injury. Due to variation in camera models and expertise of the photographer, photograph quality can affect its interpretation. Additionally, it can sometimes be days between injury and examination, allowing the injury pattern and colour to alter, making it harder to analyse., Aim: To investigate if a 3D imaging technique, creating a time-lapse image of a bite mark in three dimensions, can provide context to the injury in terms of nature and location, and also allow analysis of the change in appearance of a bite mark over time., Method: Participants had an experimental bite mark produced on their forearm by dental casts mounted on a dental articulator. The forearms were photographed immediately following the bite, and at intervals of 3, 6, 24, 48, 72 and 96 h. A DI3D(®) (Dimensional Imaging 3D) photogrammetry system and Autodesk Maya 2015(®) software was used to create a 3D animation from the images obtained. The clearest, long lasting bite mark injuries were selected for animation, enabling the 3D imaging technique to be used optimally., Results: 3D time-lapse animations were successfully created with the ability to be viewed on most electronic devices. With further refinement this technique could be valuable in a number of areas. We anticipate animations produced in this way to have significant benefit to the presentation of photographic evidence in a court setting, and in age estimation of injuries., (Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

Time-lapse technique provides opportunities to observe the dynamic process of human early development. Previous studies have suggested several abnormal division patterns were associated with decreased developmental potential, but no systematic results are currently available. In this study, seven abnormal division patterns were observed during early cleavage, and these had different effects on the further development potential of daughter blastomeres. According to the severity and occurrence of abnormal division patterns during the initial three cleavages, an embryo hierarchical classification model was developed and day 3 embryos were classified into six grades (from A to F). The good-quality blastocyst formation rate for these grades decreased from 70.8-3.8% (P < 0.001). In a prospective observational study, 139 IVF cycles were recruited to assess the efficiency of this classification model. In the embryos that had confirmed implantation results, the implantation rate decreased from 67.0% (Grade A) to 0% (Grade D;P < 0.001). These results indicated that cleavage patterns can predict the developmental potential of day 3 human embryos., (Copyright © 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Recent studies involving a limited number of patients have indicated a correlation between aneuploidy and various morphokinetic parameters during preimplantation development. The results among different groups, however, have been inconsistent in identifying the parameters that are able to predict chromosomal abnormalities. The aim of this study was to investigate whether aneuploidy of human blastocysts was detectable by specific morphokinetic parameters in patients at increased risk of aneuploidy because of advanced maternal age, history of unsuccessful IVF treatments, or both. A longitudinal cohort study was conducted using 455 blastocysts from 138 patients. Morphokinetic features of preimplantation development were detected in a timelapse incubator. Blastocysts were subjected to trophectodermal biopsy and comprehensive chromosomal screening. Analyses were conducted by means of logistic mixed-effects models, with a subject-specific intercept. No statistical correlation between 16 commonly detected morphokinetic characteristics of in-vitro embryo development and aneuploidy was found. Results suggest that morphokinetic characteristics cannot be used to select euploid blastocysts in poor-prognosis patients regarded as candidates for pre-implantation genetic screening., (Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Computer-automated time-lapse analysis has been shown to improve embryo selection by providing quantitative and objective information to supplement traditional morphology. In this multi-centre study, the relationship between such computer-derived outputs (High, Medium, Low scores), embryo implantation and clinical pregnancy were examined. Data were collected from six clinics, including 205 patients whose embryos were imaged by the Eeva(TM) System. The Eeva scores were blinded and not considered during embryo selection. Embryos with High and Medium scores had significantly higher implantation rates than those with Low scores (37% and 35% versus 15%; P < 0.0001; P = 0.0004). Similar trends in implantation rates were observed in different IVF centres each using their own protocols. Further analysis revealed that patients with at least one High embryo transferred had significantly higher clinical pregnancy rates than those with only Low embryos transferred (51% versus 34%; P = 0.02), although patients' clinical characteristics across groups were comparable. These data, together with previous research and clinical studies, confirm that computer-automated Eeva scores provide valuable information, which may improve the clinical outcome of IVF procedures and ultimately facilitate the trend of single embryo selection., (Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Introduction: The purpose of this study was 2-fold: (1) to investigate the critical time-lapse of endodontic intervention subsequent to various restorations and tooth surfaces and (2) to assess and compare the risk factors associated with the restorations, tooth surfaces, and endodontic treatment., Methods: A comprehensive computerized analysis of all dental school patients at the Case Western Reserve University School of Dental Medicine who received restorations from 2008-2013 was obtained. Inclusion and exclusion criteria were applied. The sample size was limited to teeth with endodontic treatment completed by the endodontic postgraduate dental clinic. Data collected included restoration type, restored tooth surfaces, tooth type, and the dates of restoration and subsequent endodontic treatment. A 2-sample paired t test (95% confidence interval, P < .05) and pair-wise comparison with Bonferroni corrections were implemented., Results: The mean time between restoration placement and resultant endodontic intervention was 270 days, with a mean difference of 247-294 days (P < .0001). Further analysis revealed composite resin was 1.91 times more likely than amalgam and 5.69 times more likely than crowns to cause resultant endodontic intervention. Teeth with 2 or more restorative surfaces required endodontic intervention (P < .001)., Conclusions: Of the patients who required endodontic treatment after restoration placement, the critical time-lapse was 9 months. Composite restorations and teeth with 2 or more restorative surfaces were significantly associated with endodontic treatment. From the results of the current study, we recommended that all dental practitioners should perform a thorough endodontic evaluation and diagnosis before, during, and after all restorative procedures., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Numerous studies indicate that there might be differences in embryo growth dynamics between male and female embryos. However, current data in humans are scarce and the results are inconclusive or conflicting. This study asks whether there exist gender-specific embryo development kinetics or parameters between human male and female embryos that can be observed by time-lapse technology. Study included data from 139 consecutive cycles (177 embryos transferred, 179 sacs analysed) with positive pregnancy that resulted in 100% implantation. Single- or double-embryo transfers were performed. Cases were analysed for parameters including cleavage time points and duration in each cleavage from two cells to hatching blastocyst stages and time interval between cleavages. Morphokinetic parameters of 78 female and 60 male embryos from a total of 119 cycles (139 sacs were examined after transfer of 138 embryos) were processed for data analysis according to the gender group. A detailed analysis of the data regarding each time point or interval between consecutive events according to these groups showed them to be similar in cell division kinetics, from the early cleavage through their development to blastocyst stage. However, female embryos showed earlier cavitation than male embryos, but the results did not reach statistical significance., (Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Multiple pregnancies stand as the most common adverse outcome of assisted reproduction technologies (ART) and the dangers associated with those pregnancies have been reduced by doing elective single embryo transfers (e-SET). Many studies have shown that e-SET is compatible with a continuously high pregnancy rate per embryo transfer. Yet, it still becomes necessary to improve the selection process in order to define the quality of individual embryos - so that the ones we choose for transfer are more likely to implant. First, analysis of embryo morphology has greatly helped in this identification and remains the most relevant criterion for choosing the embryo. The introduction of time-lapse imaging provides new criteria predictive of implantation potential, but the real contribution of this system - including the benefit/cost ratio - seems to be not yet properly established. In this context, extended culture until blastocyst stage is an essential practice but it appears wise to keep it for a population showing a good prognosis. Then, the failure of aneuploid embryos to implant properly led to achieve preimplantation genetic screening (PGS) in order to increase pregnancy and delivery rates after ART. However, PGS by fluorescence in situ hybridization (FISH) at day 3 is a useless process - and may even be harmful. Another solution involves using comparative genomic hybridisation (CGH) and moving to blastocyst biopsy. Finally, it is envisaged that morphology will also be significantly aided by non-invasive analysis of biomarkers in the culture media that give a better reflection of whole-embryo physiology and function., (Copyright © 2014. Published by Elsevier SAS.)

The morphology of fertilization events has been related to successful implantation by subjective criteria (pronuclei score, pronuclei symmetry and position). This work first described these events by time-lapse technology and then compared the timings of fertilization events (second polar body extrusion, first and second pronuclei appearance, abuttal and fading) in implanted versus nonimplanted embryos in a 2-year cohort retrospective study. A total of 1448 transferred embryos from 842 patients undergoing intracytoplasmic sperm injection with oocyte donation were monitored, 212 embryos from treatments where the number of gestational sacs matched the number of transferred embryos and 687 embryos from treatments no biochemical pregnancy was achieved. The timings at which second polar body extrusion (3.3-10.6 h), pronuclear fading (22.2-25.9 h) and length of S-phase (5.7-13.8 h) occurred were linked successfully to embryo implantation. The other parameters were apparently not related, as determined by image acquisition and time-lapse analysis., (Copyright © 2013 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

The potential impacts of underwater noise on marine mammals are widely recognised, but uncertainty over variability in baseline noise levels often constrains efforts to manage these impacts. This paper characterises natural and anthropogenic contributors to underwater noise at two sites in the Moray Firth Special Area of Conservation, an important marine mammal habitat that may be exposed to increased shipping activity from proposed offshore energy developments. We aimed to establish a pre-development baseline, and to develop ship noise monitoring methods using Automatic Identification System (AIS) and time-lapse video to record trends in noise levels and shipping activity. Our results detail the noise levels currently experienced by a locally protected bottlenose dolphin population, explore the relationship between broadband sound exposure levels and the indicators proposed in response to the EU Marine Strategy Framework Directive, and provide a ship noise assessment toolkit which can be applied in other coastal marine environments., (Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The physico-chemical processes and phenomena occurring at the interface of metallic biomedical implants and the body dictate their successful integration in vivo. Changes in the surface potential and the associated redox reactions at metallic implants can significantly influence several aspects of biomaterial/cell interactions such as cell adhesion and survival in vitro. Accordingly, there is a voltage viability range (voltages which do not compromise cellular viability of the cells cultured on the polarized metal) for metallic implants. We report on cellular dynamics (size, polarity, movement) and temporal changes in the number and total area of focal adhesion complexes in transiently transfected MC3T3-E1 pre-osteoblasts cultured on CoCrMo alloy surfaces polarized at the cathodic and anodic edges of its voltage viability range (-400 and +500 mV (Ag/AgCl), respectively). Nucleus dynamics (size, circularity, movement) and the release of reactive oxygen species (ROS) were also studied on the polarized metal at -1000, -400 and +500 mV (Ag/AgCl). Our results show that at -400 mV, where reduction reactions dominate, a gradual loss of adhesion occurs over 24 h while cells shrink in size during this time. At +500 mV, where oxidation reactions dominate (i.e. metal ions form, including Cr6+), cells become non-viable after 5h without showing any significant changes in adhesion behavior right before cell death. Nucleus size of cells at -1000 mV decreased sharply within 15 min after polarization, which rendered the cells completely non-viable. No significant amount of ROS release by cells was detected on the polarized CoCrMo at any of these voltages., (Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Because sperm vacuoles were marked as zones without chromatin in the sperm nucleus, which may reflect underlying chromosomal or DNA defects, this study considered whether they influence the morphology and dynamics of early developmental events in preimplantation embryos. Oocytes were injected with spermatozoa of four classes, according to the number and size of vacuoles at ×6000 magnification, and derived embryos were observed under time-lapse microscopy. For each embryo, the times of pronuclei appearance and disappearance and the first, second and third divisions were determined and related to its respective class of injected spermatozoa and its developmental stage. Embryos arising from normal class-I spermatozoa (without vacuoles) reached the 4-cell stage significantly earlier than embryos developed from class-IV spermatozoa (with large vacuoles and other abnormalities) (P=0.012). Blastocysts from class-I spermatozoa required the shortest mean time for all developmental events in comparison with blastocysts from spermatozoa of other classes (with vacuoles). Blastocysts also showed significantly earlier first division than arrested embryos in embryos arising from class-I spermatozoa (P=0.033). An insight into the developmental dynamics of embryo development according to morphology and head vacuoles of injected spermatozoa in morphologically selected sperm-derived embryos was observed for the first time., (Copyright © 2013 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)