Is morphokinetic analysis the answer?

MicroRNAomic Analysis of Spent Media from Slow- and Fast-Growing Bovine Embryos Reveal Distinct Differences

In bovine embryos, the microRNA (miRNA) expression has been profiled at each stage of early development in vitro. The miRNAomic analysis of spent media has the potential to reveal characteristics of embryo health; however, applications are limited without categorizing miRNA profiles by embryo quality. Time-lapse imaging has shown the timing of embryo development in vitro may be indicative of their developmental potential. The study aimed to characterize miRNAs in the spent media of bovine embryos with different growth rates during the pre-implantation phase. Bovine cumulus-oocyte complexes were aspirated from ovaries, fertilized, and cultured to blastocyst stage of development. At the 2-cell, 8-cell, and blastocyst stage, each microdrop of 30 presumptive zygotes were classified as slow- or fast-growing based on the percentage of embryos that had reached the desired morphological stage. A comparative analysis was performed on the spent media of slow- and fast-growing embryos using the results of a GeneChip miRNA 4.0 array hybridization. In total, 34 differentially expressed miRNAs were identified between the comparison groups: 14 miRNAs were found in the 2-cell samples, 7 in the 8-cell samples, and 12 in the blastocyst samples. The results demonstrate distinct miRNAs populations can be identified between slow- and fast-growing embryos, highlighting the novel biomarkers of developmental potential at each stage of pre-implantation development.

The Antioxidant Salidroside Ameliorates the Quality of Postovulatory Aged Oocyte and Embryo Development in Mice

Postovulatory aging is known to impair the oocyte quality and embryo development due to oxidative stress in many different animal models, which reduces the success rate or pregnancy rate in human assisted reproductive technology (ART) and livestock timed artificial insemination (TAI), respectively. Salidroside (SAL), a phenylpropanoid glycoside, has been shown to exert antioxidant and antitumor effects. This study aimed to investigate whether SAL supplementation could delay the postovulatory oocyte aging process by alleviating oxidative stress. Here, we show that SAL supplementation decreases the malformation rate and recovers mitochondrial dysfunction including mitochondrial distribution, mitochondrial membrane potential (ΔΨ) and ATP content in aged oocytes. In addition, SAL treatment alleviates postovulatory aging-caused oxidative stress such as higher reactive oxygen species (ROS) level, lower glutathione (GSH) content and a reduced expression of antioxidant-related genes. Moreover, the cytoplasmic calcium ([Ca2+]c) and mitochondrial calcium ([Ca2+]mt) of SAL-treated oocytes return to normal levels. Notably, SAL suppresses the aging-induced DNA damage, early apoptosis and improves spindle assembly in aged oocytes, ultimately elevating the embryo developmental rates and embryo quality. Finally, the RNA-seq and confirmatory experience showed that SAL promotes protective autophagy in aged oocytes by activating the MAPK pathway. Taken together, our research suggests that supplementing SAL is an effective and feasible method for preventing postovulatory aging and preserving the oocyte quality, which potentially contributes to improving the successful rate of ART or TAI.

The effect of embryo selection using time-lapse monitoring on IVF/ICSI outcomes: A systematic review and meta-analysis

AIM

To explore the effect of embryo selection using the time-lapse monitoring (TLM) system compared with conventional morphological selection (CMS) on in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes.

METHODS

We searched PubMed, Ovid-Embase, and The Cochrane Library for the following studies: At Comparison 1, embryo selection using TLM images in a TLM incubator based on morphology versus embryo selection using CMS in a conventional incubator based on morphology; at Comparison 2, embryo selection using TLM based on morphokinetics versus embryo selection using CMS based on morphology. The primary outcomes were the live birth rate (LBR), ongoing pregnancy rate (OPR), clinical pregnancy rate (CPR), and implantation rate (IR), and the secondary outcome was the miscarriage rate (MR).

RESULTS

A total of 14 randomized control trials (RCTs) were included. Both based on morphology, TLM incubators increased the IR (risk ratio [RR]: 1.10; 95% confidence interval [CI]: 1.01, 1.18; I2  = 0%, moderate-quality evidence) compared to conventional incubators. Low- to moderate-quality evidence suggests that TLM incubators did not improve LBR, OPR, CPR, and MR compared to conventional incubators. In addition, low- to moderate-quality evidence indicates that embryo selection using TLM based on morphokinetics did not improve LBR, OPR, CPR, IR, or MR compared to CMS based on morphology.

CONCLUSIONS

Low- to moderate-quality evidence suggests that neither TLM incubators nor embryo selection using TLM based on morphokinetics improved clinical outcomes (LBR, OPR, CPR, and MR) compared with CMS based on morphology. TLM is still an investigational procedure for IVF/ICSI practice.

A comparison of the morphokinetic profiles of embryos developed from vitrified versus fresh oocytes

RESEARCH QUESTION

Do morphokinetic profiles and treatment outcomes differ between embryos developed from vitrified or fresh oocytes?

DESIGN

Retrospective multicentre analysis using data from eight CARE Fertility clinics across the UK between 2012 and 2019. Patients receiving treatment using embryos developed from vitrified oocytes (n = 118 women, n = 748 oocytes), providing 557 zygotes during this time period, were recruited and matched with patients undergoing treatment with embryos developed from fresh oocytes (n = 123 women, n = 1110 oocytes), providing 539 zygotes in the same time frame. Time-lapse microscopy was used to assess morphokinetic profiles, including early cleavage divisions (2- through to 8-cell), post-cleavage stages including time to start of compaction, time to morula, time to start of blastulation and time to full blastocyst. Duration of key stages such as the compaction stage were also calculated. Treatment outcomes were compared between the two groups (live birth rate, clinical pregnancy rate and implantation rate).

RESULTS

A significant delay of 2-3 h across all early cleavage divisions (2- through to 8-cell) and time to start of compaction occurred in the vitrified group versus fresh controls (all P ≤ 0.01). The compaction stage was significantly shorter in vitrified oocytes (19.02 ± 0.5 h) compared with fresh controls (22.45 ± 0.6 h, P < 0.001). There was no difference in the time that fresh and vitrified embryos reached the blastocyst stage (108.03 ± 0.7 versus 107.78 ± 0.6 h). There was no significant difference in treatment outcomes between the two groups.

CONCLUSION

Vitrification is a useful technique for extending female fertility with no effects on IVF treatment outcome.

Clinical outcomes of uninterrupted embryo culture with or without time-lapse-based embryo selection versus interrupted standard culture (SelecTIMO): a three-armed, multicentre, double-blind, randomised controlled trial

BACKGROUND

Time-lapse monitoring is increasingly used in fertility laboratories to culture and select embryos for transfer. This method is offered to couples with the promise of improving pregnancy chances, even though there is currently insufficient evidence for superior clinical results. We aimed to evaluate whether a potential improvement by time-lapse monitoring is caused by the time-lapse-based embryo selection method itself or the uninterrupted culture environment that is part of the system.

METHODS

In this three-armed, multicentre, double-blind, randomised controlled trial, couples undergoing in-vitro fertilisation or intracytoplasmic sperm injection were recruited from 15 fertility clinics in the Netherlands and randomly assigned using a web-based, computerised randomisation service to one of three groups. Couples and physicians were masked to treatment group, but embryologists and laboratory technicians could not be. The time-lapse early embryo viability assessment (EEVA; TLE) group received embryo selection based on the EEVA time-lapse selection method and uninterrupted culture. The time-lapse routine (TLR) group received routine embryo selection and uninterrupted culture. The control group received routine embryo selection and interrupted culture. The co-primary endpoints were the cumulative ongoing pregnancy rate within 12 months in all women and the ongoing pregnancy rate after fresh single embryo transfer in a good prognosis population. Analysis was by intention to treat. This trial is registered on the ICTRP Search Portal, NTR5423, and is closed to new participants.

FINDINGS

1731 couples were randomly assigned between June 15, 2017, and March 31, 2020 (577 to the TLE group, 579 to the TLR group, and 575 to the control group). The 12-month cumulative ongoing pregnancy rate did not differ significantly between the three groups: 50·8% (293 of 577) in the TLE group, 50·9% (295 of 579) in the TLR group, and 49·4% (284 of 575) in the control group (p=0·85). The ongoing pregnancy rates after fresh single embryo transfer in a good prognosis population were 38·2% (125 of 327) in the TLE group, 36·8% (119 of 323) in the TLR group, and 37·8% (123 of 325) in the control group (p=0·90). Ten serious adverse events were reported (five TLE, four TLR, and one in the control group), which were not related to study procedures.

INTERPRETATION

Neither time-lapse-based embryo selection using the EEVA test nor uninterrupted culture conditions in a time-lapse incubator improved clinical outcomes compared with routine methods. Widespread application of time-lapse monitoring for fertility treatments with the promise of improved results should be questioned.

FUNDING

Health Care Efficiency Research programme from Netherlands Organisation for Health Research and Development and Merck.

Influence of a hyaluronan-binding system for sperm selection in intracytoplasmic sperm injection cycles on embryo morphokinetic parameters and in vitro fertilization cycle outcomes

PURPOSE

Although the impact of the paternal contribution to embryo quality and blastocyst formation is a well-known phenomenon, the current literature provides insufficient evidence that hyaluronan-binding sperm selection methods improve assisted reproductive treatment outcomes. Thus, we compared the cycle outcomes of morphologically selected intracytoplasmic sperm injection (ICSI) with hyaluronan binding physiological intracytoplasmic sperm injection (PICSI) cycles.

METHODS

A total of 2415 ICSI and 400 PICSI procedures of 1630 patients who underwent in vitro fertilization cycles using a time-lapse monitoring system between 2014 and 2018 were analyzed retrospectively. Fertilization rate, embryo quality, clinical pregnancy rate, biochemical pregnancy rate and miscarriage rate were evaluated, differences in morphokinetic parameters and cycle outcomes were compared.

RESULTS

In total, 85.8 and 14.2% of the whole cohort were fertilized with standard ICSI and PICSI, respectively. The proportion of fertilized oocytes did not significantly differ between groups (74.53 ± 1.33 vs. 72.92 ± 2.64, p > 0.05). Similarly, the proportion of good-quality embryos according to the time-lapse parameters and the clinical pregnancy rate did not significantly differ between groups (71.93 ± 4.21 vs. 71.33 ± 2.64, p > 0.05 and 45.55 ± 2.91 vs. 44.96 ± 1.25, p > 0.05). No statistically significant differences were found between groups in clinical pregnancy rates (45.55 ± 2.91 vs. 44.96 ± 1.25, p > 0.05). Biochemical pregnancy rates (11.24 ± 2.12 vs. 10.85 ± 1.83, p > 0.05) and miscarriage rates (24.89 ± 3.74 vs. 27.91 ± 4.91, p > 0.05) were not significantly different between groups.

CONCLUSION

The effects of the PICSI procedure on fertilization rate, biochemical pregnancy rate, miscarriage rate, embryo quality, and clinical pregnancy outcomes were not superior. The effect of the PICSI procedure on embryo morphokinetics was not apparent when all parameters were considered.

The Antioxidant Auraptene Improves Aged Oocyte Quality and Embryo Development in Mice

Decrease in quality of postovulatory aged oocytes occurs due to oxidative stress and leads to low fertilization and development competence. It is one of the main causes that exerting detrimental effect on the success rate in assisted reproductive technology (ART). Auraptene (AUR), a citrus coumarin, has been reported to possess an antioxidant effects in other tissues. In this study, we aimed to confirm the potential of AUR to delay the oocyte aging process by alleviating oxidative stress. Superovulated mouse oocytes in metaphase of second meiosis (MII) were exposed to 0, 1 or 10 μM AUR for 12 h of in vitro aging. AUR addition to the culture medium recovered abnormal spindle and chromosome morphology and mitigated mitochondrial distribution and mitochondrial membrane potential (ΔΨ) in aged oocytes. AUR-treated aged oocytes also showed suppressed oxidative stress, with lower reactive oxygen species (ROS) levels, higher glutathione (GSH) levels and increased expression of several genes involved in antioxidation. Furthermore, AUR significantly elevated the fertilization and embryo developmental rates. Oocytes aged with 1 μM AUR exhibited morphokinetics that were very similar to those of the control group. Altogether, these data allowed us to conclude that AUR improved the quality of aged oocytes and suggest AUR as an effective clinical supplement candidate to prevent postovulatory aging.

Embryonic Development in Relation to Maternal Obesity Does Not Affect Pregnancy Outcomes in FET Cycles

This retrospective cohort study examined the effect of maternal BMI on embryo morphokinetics using a time-lapse incubator (TLI) and evaluated the effect on outcomes of frozen embryo transfer (FET) cycles. The study included 641 women who underwent FET of a total of 2553 embryos from January 2017 to August 2019. The women were divided into four groups according to BMI: underweight (<18.5 kg/m2), normal weight (18.5−24.99 kg/m2), overweight (25.0−29.99 kg/m2), and obese (≥30 kg/m2). Embryos were transferred on day 3 or 5, and their development was monitored using a TLI. We found that oocytes from obese patients were slower in the extraction of the second polar body (tPB2) after fertilization and the two pronucleus stage appeared later compared to normal-weight women. The time to fading of the pronucleus (tPNf), t2, and t4 were comparable between the four groups. Oocytes from underweight and overweight women had significantly faster cleavage at t3 and t5−t8 compared to normal weight. We did not find any significant difference in pregnancy rate, clinical pregnancy rate, or miscarriage rate among groups. In conclusion, embryos from normal-weight patients had slower cleavage rates compared to obese patients, while embryo quality was similar between BMI groups. The cycle outcomes demonstrated comparable pregnancy rates among the BMI groups.

Noninvasive embryo evaluation and selection by time-lapse monitoring vs. conventional morphologic assessment in women undergoing in vitro fertilization/intracytoplasmic sperm injection: a single-center randomized controlled study

OBJECTIVE

To determine whether time-lapse monitoring (TLM) for cleavage-stage embryo selection improves reproductive outcomes in comparison with conventional morphological assessment (CMA) selection.

DESIGN

Prospective randomized controlled trial.

SETTING

Single academic center.

PATIENTS

We randomly assigned 139 women who were undergoing their first in vitro fertilization or intracytoplasmic sperm injection cycle to undergo either fresh embryo transfer or first frozen embryo transfer (FET). Only 1 cleavage-stage embryo was transferred to each participant.

INTERVENTIONS

The patients were randomly assigned to either the CMA or the TLM group. In the CMA group, day 2 and day 3 embryos were observed. A good-quality cleavage-stage embryo was selected for transfer or freezing in both groups.

MAIN OUTCOME MEASURES

The primary and secondary outcomes were the clinical pregnancy rate (CPR) and the live birth rate (LBR), respectively, after the first embryo transfer (fresh embryo transfer or FET).

RESULTS

The CPR and LBR were significantly lower in the TLM group than in the CMA group (CPR: 49.18% vs. 70.42%; relative risk, 0.70; 95% confidence interval [CI], 0.52-0.94; LBR: 45.90% vs. 64.79%; relative risk, 0.71; 95% CI, 0.51-0.98). The CPR with fresh embryo transfer or FET did not significantly differ between the TLM and the CMA groups (fresh embryo transfer: 44.44% vs. 70.0%, relative risk, 0.63, 95% CI, 0.39-1.03; FET: 52.94% vs. 70.73%, relative risk, 0.75, 95% CI, 0.52-1.09). There was a significant difference in the LBR with fresh embryo transfer between the TLM and the CMA groups (40.74% vs. 66.67%; relative risk, 0.61; 95% CI, 0.36-1.03). The LBRs with FET were similar in the TLM and the CMA groups (50.0% vs. 63.41%; relative risk, 0.79; 95% CI, 0.52-1.19). The rates of early spontaneous abortion and ectopic pregnancy did not differ between the TLM and the CMA groups.

CONCLUSIONS

Elective single cleavage-stage embryo transfer with TLM-based selection did not have any advantages over CMA when day 2 and day 3 embryo morphology was combined in young women with a good ovarian reserve. Because of these results, we conclude that TLM remains an investigational procedure for in vitro fertilization practice.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR1900021981.

Using deep learning to predict the outcome of live birth from more than 10,000 embryo data

Background

Recently, the combination of deep learning and time-lapse imaging provides an objective, standard and scientific solution for embryo selection. However, the reported studies were based on blastocyst formation or clinical pregnancy as the end point. To the best of our knowledge, there is no predictive model that uses the outcome of live birth as the predictive end point. Can a deep learning model predict the probability of live birth from time-lapse system?

Methods

This study retrospectively analyzed the time-lapse data and live birth outcomes of embryos samples from January 2018 to November 2019. We used the SGD optimizer with an initial learning rate of 0.025 and cosine learning rate reduction strategy. The network is randomly initialized and trained for 200 epochs from scratch. The model is quantitively evaluated over a hold-out test and a 5-fold cross-validation by the average area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

Results

The deep learning model was able to predict live birth outcomes from time-lapse images with an AUC of 0.968 in 5-fold stratified cross-validation.

Conclusions

This research reported a deep learning model that predicts the live birth outcome of a single blastocyst transfer. This efficient model for predicting the outcome of live births can automatically analyze the time-lapse images of the patient’s embryos without the need for manual embryo annotation and evaluation, and then give a live birth prediction score for each embryo, and sort the embryos by the predicted value.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04373-5.

Non-invasive, label-free optical analysis to detect aneuploidy within the inner cell mass of the preimplantation embryo

STUDY QUESTION

Can label-free, non-invasive optical imaging by hyperspectral autofluorescence microscopy discern between euploid and aneuploid cells within the inner cell mass (ICM) of the mouse preimplantation embryo?

SUMMARY ANSWER

Hyperspectral autofluorescence microscopy enables discrimination between euploid and aneuploid ICM in mouse embryos.

WHAT IS KNOWN ALREADY

Euploid/aneuploid mosaicism affects up to 17.3% of human blastocyst embryos with trophectoderm biopsy or spent media currently utilized to diagnose aneuploidy and mosaicism in clinical in vitro fertilization. Based on their design, these approaches will fail to diagnose the presence or proportion of aneuploid cells within the foetal lineage ICM of some blastocyst embryos.

STUDY DESIGN, SIZE, DURATION

The impact of aneuploidy on cellular autofluorescence and metabolism of primary human fibroblast cells and mouse embryos was assessed using a fluorescence microscope adapted for imaging with multiple spectral channels (hyperspectral imaging). Primary human fibroblast cells with known ploidy were subjected to hyperspectral imaging to record native cell fluorescence (4-6 independent replicates, euploid n = 467; aneuploid n = 969). For mouse embryos, blastomeres from the eight-cell stage (five independent replicates: control n = 39; reversine n = 44) and chimeric blastocysts (eight independent replicates: control n = 34; reversine n = 34; 1:1 (control:reversine) n = 30 and 1:3 (control:reversine) n = 37) were utilized for hyperspectral imaging. The ICM from control and reversine-treated embryos were mechanically dissected and their karyotype confirmed by whole genome sequencing (n = 13 euploid and n = 9 aneuploid).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two models were employed: (i) primary human fibroblasts with known karyotype and (ii) a mouse model of embryo aneuploidy where mouse embryos were treated with reversine, a reversible spindle assembly checkpoint inhibitor, during the four- to eight-cell division. Individual blastomeres were dissociated from control and reversine-treated eight-cell embryos and either imaged directly or used to generate chimeric blastocysts with differing ratios of control:reversine-treated cells. Individual blastomeres and embryos were interrogated by hyperspectral imaging. Changes in cellular metabolism were determined by quantification of metabolic co-factors (inferred from their autofluorescence signature): NAD(P)H and flavins with the subsequent calculation of the optical redox ratio (ORR: flavins/[NAD(P)H + flavins]). Autofluorescence signals obtained from hyperspectral imaging were examined mathematically to extract features from each cell/blastomere/ICM. This was used to discriminate between different cell populations.

MAIN RESULTS AND THE ROLE OF CHANCE

An increase in the relative abundance of NAD(P)H and decrease in flavins led to a significant reduction in the ORR for aneuploid cells in primary human fibroblasts and reversine-treated mouse blastomeres (P < 0.05). Mathematical analysis of endogenous cell autofluorescence achieved separation between (i) euploid and aneuploid primary human fibroblast cells, (ii) control and reversine-treated mouse blastomeres cells, (iii) control and reversine-treated chimeric blastocysts, (iv) 1:1 and 1:3 chimeric blastocysts and (v) confirmed euploid and aneuploid ICM from mouse blastocysts. The accuracy of these separations was supported by receiver operating characteristic curves with areas under the curve of 0.97, 0.99, 0.87, 0.88 and 0.93, respectively. We believe that the role of chance is low as mathematical features separated euploid from aneuploid in both human fibroblasts and ICM of mouse blastocysts.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Although we were able to discriminate between euploid and aneuploid ICM in mouse blastocysts, confirmation of this approach in human embryos is required. While we show this approach is safe in mouse, further validation is required in large animal species prior to implementation in a clinical setting.

WIDER IMPLICATIONS OF THE FINDINGS

We have developed an original, accurate and non-invasive optical approach to assess aneuploidy within the ICM of mouse embryos in the absence of fluorescent tags. Hyperspectral autofluorescence imaging was able to discriminate between euploid and aneuploid human fibroblast and mouse blastocysts (ICM). This approach may potentially lead to a new diagnostic for embryo analysis.

STUDY FUNDING/COMPETING INTEREST(S)

K.R.D. is supported by a Mid-Career Fellowship from the Hospital Research Foundation (C-MCF-58-2019). This study was funded by the Australian Research Council Centre of Excellence for Nanoscale Biophotonics (CE140100003) and the National Health and Medical Research Council (APP2003786). The authors declare that there is no conflict of interest.

Optical imaging of cleavage stage bovine embryos using hyperspectral and confocal approaches reveals metabolic differences between on-time and fast-developing embryos

The assessment of embryo quality aims to enhance subsequent pregnancy and live birth outcomes. Metabolic analysis of embryos has immense potential in this regard. As a step towards this goal, here we assess the metabolism of bovine embryos using label-free optical imaging. We compared embryos defined as either on-time or fast-developing, as fast dividing embryos are more likely to develop to the blastocyst stage. Specifically, bovine embryos at 48 (Day 2) and 96 (Day 4) hours post fertilization were fixed and separated based on morphological assessment: on-time (Day 2: 2 cell; Day 4: 5-7 cell) or fast-developing (Day 2: 3-7 cell; Day 4: 8-16 cell). Embryos with different developmental rates on Day 2 and Day 4 were correlated with metabolic activity and DNA damage. Confocal microscopy was used to assess metabolic activity by quantification of cellular autofluorescence specific for the endogenous fluorophores NAD(P)H and FAD with a subsequent calculation of the optical redox ratio. Separately, hyperspectral microscopy was employed to assess a broader range of endogenous fluorophores. DNA damage was determined using γH2AX immunohistochemistry. Hyperspectral imaging showed significantly lower abundance of endogenous fluorophores in fast-developing compared to on-time embryos on Day 2, indicating a lower metabolic activity. On Day 4 of development there was no difference in the abundance of FAD between on-time and fast-developing embryos. There was, however, significantly higher levels of NAD(P)H in fast-developing embryos leading to a significantly lower optical redox ratio when compared to on-time embryos. Collectively, these results demonstrate that fast-developing embryos present a 'quiet' metabolic pattern on Day 2 and Day 4 of development, compared to on-time embryos. There was no difference in the level of DNA damage between on-time and fast-developing embryos on either day of development. To our knowledge, this is the first collective use of confocal and hyperspectral imaging in cleavage-stage bovine embryos in the absence of fluorescent tags.

Novel and conventional embryo parameters as input data for artificial neural networks: an artificial intelligence model applied for prediction of the implantation potential

OBJECTIVE

To describe novel embryo features capable of predicting implantation potential as input data for an artificial neural network (ANN) model.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated private IVF center.

PATIENT(S)

This study included 637 patients from the oocyte donation program who underwent single-blastocyst transfer during two consecutive years.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The research was divided into two phases. Phase 1 consisted of the description and analysis of the following embryo features in implanted and nonimplanted embryos: distance and speed of pronuclear migration, blastocyst expanded diameter, inner cell mass area, and trophectoderm cell cycle length. Phase 2 consisted of the development of an ANN algorithm for implantation prediction. Results were obtained for four models fed with different input data. The predictive power was measured with the use of the area under the receiver operating characteristic curve (AUC).

RESULT(S)

Out of the five novel described parameters, blastocyst expanded diameter and trophectoderm cell cycle length had statistically different values in implanted and nonimplanted embryos. After the ANN models were trained and validated using fivefold cross-validation, they were capable of predicting implantation on testing data with AUCs of 0.64 for ANN1 (conventional morphokinetics), 0.73 for ANN2 (novel morphodynamics), 0.77 for ANN3 (conventional morphokinetics + novel morphodynamics), and 0.68 for ANN4 (discriminatory variables from statistical test).

CONCLUSION(S)

The novel proposed embryo features affect the implantation potential, and their combination with conventional morphokinetic parameters is effective as input data for a predictive model based on artificial intelligence.

Preimplantation Genetic Testing for Aneuploidy: A Review

Importance

Preimplantation genetic testing for aneuploidy (PGT-A) has undergone many technical developments over recent years, including changes in biopsy timings, methodology, and genetic analysis techniques. The evidence surrounding the efficaciousness of PGT-A is sporadic and inconsistent; as such, significant doubt and concern remain regarding its widespread implementation.

Objective

This review seeks to describe the historical development of PGT-A and to analyze and summarize the current published literature.

Conclusions

At times during its infancy, PGT-A failed to display conclusive improvements in results; with newer technologies, PGT-A appears to yield superior outcomes, including reductions in miscarriages and multiple gestations. Clinicians and patients should assess the use of PGT-A on a case-by-case basis, with laboratories encouraged to utilize blastocyst biopsy and next-generation sequencing when conducting PGT-A. Further studies providing cumulative live birth rates and time to live birth are required if PGT-A is to be proven as producing superior outcomes.

Relevance

PGT-A has the potential ability to impact in vitro fertilization success rates, and as it is increasingly adopted worldwide, it is crucial that clinicians are aware of the evidence for its continued use.

Lipid characterization of in vitro-produced bovine embryos with distinct kinetics of development

Human embryo studies have proposed the use of additional morphological evaluations related to the moment of the first cell divisions as relevant to embryo viability. Nevertheless, there are still not enough data available related to morphokinetic analysis and its relationship with lipid composition in embryos. Therefore, the aim of this study was to address the lipid profile of bovine embryos with different developmental kinetics: fast (four or more cells) and slow (two or three cells) at 40 h post-insemination (hpi), at three time points of in vitro culture (40, 112 and 186 hpi) and compare these to profiles of in vivo embryos. The lipid profiles of embryos were analyzed by matrix-assisted laser desorption ionization mass spectrometry, which mainly detected pools of membrane lipids such as phosphatidylcholine and sphingomyelin. In addition to their structural function, these lipid classes have an important role in cell signalling, particularly regarding events such as stress and pregnancy. Different patterns of lipids in the fast and slow groups were revealed in all the analyzed stages. Also, differences between in vitro embryos were more pronounced at 112 hpi, a critical moment due to embryonic genome activation. At the blastocyst stage, in vitro-produced embryos, despite the kinetics, had a closer lipid profile when compared with in vivo blastocysts. In conclusion, the kinetics of development had a greater effect on the membrane lipid profiles throughout the embryo culture, especially at the 8-16-cell stage. The in vitro environment affects lipid composition and may compromise cell signalling and function in blastocysts.

Double-stranded sperm DNA damage is a cause of delay in embryo development and can impair implantation rates

OBJECTIVE

To analyze the effect of single- and double-stranded sperm DNA fragmentation (ssSDF and dsSDF) on human embryo kinetics monitored under a time-lapse system.

DESIGN

Observational, double blind, prospective cohort study.

SETTING

University spin-off and private center.

PATIENT(S)

One hundred ninety-six embryos from 43 infertile couples were included prospectively.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

SsSDF and dsSDF were analyzed in the same semen sample used for intracytoplasmic sperm injection. Embryo kinetics was then monitored using time-lapse technology, and the timing of each embryo division was obtained.

RESULT(S)

When comparing embryos obtained from semen samples with low dsSDF and high dsSDF, splitting data using a statistically significant delay in high dsSDF was observed in second polar body extrusion, T4, T8, morula, and starting blastocyst and embryo implantation rates were impaired. Embryo kinetics and implantation rates are not significantly affected when high values of ssSDF are present. Different patterns of delay in embryo kinetics were observed for these different types of DNA damage: dsSDF caused a delay along all stages of embryo development; however, its major effect was observed at the second polar body extrusion and morula stages, coinciding with embryo DNA damage checkpoint activation as described before; ssSDF had its major effect at the pronucleus stage, but embryo kinetics was then restored at all following stages. The results show that dsSDF could be the main type of DNA damage that affects embryo development in intracytoplasmic sperm injection cycles, probably due to motility-based sperm selection in this assisted reproduction procedure.

CONCLUSION(S)

Double-stranded sperm DNA damage caused a delay in embryo development and impaired implantation, while single-stranded DNA damage did not significantly affect embryo kinetics and implantation.

Comparison of the development of human embryos cultured in either an EmbryoScope or benchtop incubator

PURPOSE

In this current study, our main goal was to establish that EmbryoScope incubation environment is comparable to standard incubation.

METHODS

The development of sibling human zygotes was compared after culture in either a benchtop incubator (SI) or an EmbryoScope time-lapse incubator (ES). Between May 2015 to April 2016, a total of 581 normally fertilized 2PN, pronuclear-stage embryos, from 47 patients were allocated to culture in either a benchtop incubator (SI) or an EmbryoScope incubator (ES).

RESULTS

The development of embryos to cleavage (up to day 3) and blastocyst stages (day 5/6) was compared between the two different incubators. The proportion of good quality embryos was higher in the ES group compared to the SI on day 2 (66.8 vs. 50.5%, P = 0.014) and on day 3 (75.1 vs. 56.0%, P = 0.006). Those differences were statistically significant. A higher proportion of embryos developed to good quality blastocysts when cultured in the EmbryoScope compared to the benchtop (49.4 vs. 42.0%, P = 0.24), but this was not significant. Finally, no significant differences were noted with the proportion of blastocysts chosen for cryopreservation on day 5/6 in the two incubators.

CONCLUSIONS

The findings support the view that the EmbryoScope incubator supports at least equivalent in vitro development of human embryos compared to other standard incubation methods and may promote improved development during early cleavage stages.

Role of microRNAs in embryo implantation

Failure of embryo implantation is a major limiting factor in early pregnancy and assisted reproduction. Determinants of implantation include the embryo viability, the endometrial receptivity, and embryo-maternal interactions. Multiple molecules are involved in the regulation of implantation, but their specific regulatory mechanisms remain unclear. MicroRNA (miRNA), functioning as the transcriptional regulator of gene expression, has been widely reported to be involved in embryo implantation. Recent studies reveal that miRNAs not only act inside the cells, but also can be released by cells into the extracellular environment through multiple packaging forms, facilitating intercellular communication and providing indicative information associated with physiological and pathological conditions. The discovery of extracellular miRNAs shed new light on implantation studies. MiRNAs provide new mechanisms for embryo-maternal communication. Moreover, they may serve as non-invasive biomarkers for embryo selection and assessment of endometrial receptivity in assisted reproduction, which improves the accuracy of evaluation while reducing the mechanical damage to the tissue. In this review, we discuss the involvement of miRNAs in embryo implantation from several aspects, focusing on the role of extracellular miRNAs and their potential applications in assisted reproductive technologies (ART) to promote fertility efficiency.

Dynamics of cytoplasm and cleavage divisions correlates with preimplantation embryo development

In vitro fertilization has become increasingly popular as an infertility treatment. In order to improve efficiency of this procedure, there is a strong need for a refinement of existing embryo assessment methods and development of novel, robust and non-invasive selection protocols. Studies conducted on animal models can be extremely helpful here, as they allow for more extensive research on the potential biomarkers of embryo quality. In the present paper, we subjected mouse embryos to non-invasive time-lapse imaging and combined the Particle Image Velocimetry analysis of cytoplasmic dynamics in freshly fertilized oocytes with the morphokinetic analysis of recordings covering 5 days of preimplantation development. Our results indicate that parameters describing cytoplasmic dynamics and cleavage divisions independently correspond to mouse embryo's capacity to form a high-quality blastocyst. We also showed for the first time that these parameters are associated with the percentage of abnormal embryonic cells with fragmented nuclei and with embryo's ability to form primitive endoderm, one of the cell lineages differentiated during preimplantation development. Finally, we present a model that links selected cytoplasmic and morphokinetic parameters reflecting frequency of fertilization-induced Ca²⁺-oscillations and timing of 4-cell stage and compaction with viability of the embryo assessed as the total number of cells at the end of its preimplantation development. Our results indicate that a combined analysis of cytoplasmic dynamics and morphokinetics may facilitate the assessment of embryo's ability to form high-quality blastocysts.

Comparison of the morphokinetic parameters of embryos according to ovarian reserve in IVF cycles

The aim of this study is to evaluate the impact of ovarian reserve and age of women on early morphokinetic parameters of embryos with a time-lapse monitoring system. In total, 197 infertile couples with poor ovarian reserve (Group 1, n = 41), normal ovarian reserve (Group 2, n = 59), or polycystic ovaries (Group 3, n = 97) were included. The time from insemination to the following events were analyzed: pronuclear fading (Pnf) and cleavage to 2, 3, 4 and 5 cells. The optimal ranges for morphokinetic parameters of t5, s2 and cc2 in each group were also evaluated. In total, 1144 embryos were evaluated. Morphokinetic parameters did not differ statistically between the groups. Data were analyzed according to different age groups (20-30, 30-40, >40). The morphokinetic parameters did not differ statistically in Group 1 and 3. In Group 2, the times from insemination to tPnf, t2, t3, t4 were significantly shorter in the younger age group than the older age group (p < 0.05). The percentages of optimal embryos, according to t5, s2 and cc2, did not differ statistically between the groups. In conclusion, ovarian reserve did not seem to affect the morphokinetic parameters of embryos.

Time-lapse imaging of cleavage divisions in embryo quality assessment

In vitro fertilization (IVF) is one of the most important procedures for treating infertility. As several embryos are usually produced in a single IVF cycle, it is crucial to select only the most viable ones for transfer to the patient. Morphokinetics, i.e. analysis of the dynamics of cleavage divisions and processes such as compaction and cavitation, has provided both biologists and clinicians with a new set of data regarding embryonic behaviour during preimplantation development and its association with embryo quality. In the current review, we focus on biological significance of morphokinetic parameters and show how they can be used to predict a reproductive outcome. We also explain the statistics behind the predictive algorithms and discuss the future perspectives of morphokinetics.

The association between coenzyme Q10 concentrations in follicular fluid with embryo morphokinetics and pregnancy rate in assisted reproductive techniques

PURPOSE

This study seeks to evaluate the association between follicular fluid (FF) coenzyme Q10 (CoQ10) levels, embryo morphokinetics, and pregnancy rate.

METHODS

Sixty infertile patients who underwent intracytoplasmic sperm injection (ICSI) cycles were included in the study. For each patient, CoQ10 level of the follicular fluid was measured by high-performance liquid chromatography system. After the ICSI of each oocyte, the relationship between the level of CoQ10 content of each follicular fluid, the subsequent embryo quality, and embryo morphokinetics was investigated. The relationship between the level of CoQ10 content of each follicle and optimal time-lapse parameters for the embryos of these follicles including t5, s2, and cc2 was also analyzed. The embryos were further classified into four categories, namely, grades A, B, C, and D, according to morphokinetic parameters using t5-t2 and t5-t3 (cc3). Each follicular fluid analysis was performed for a single oocyte of a single embryo which was transferred to the patients. Additionally, follicular fluid CoQ10 levels and pregnancy rates were evaluated.

RESULTS

Follicular fluid CoQ10 levels were significantly higher in grades A and B than grades C and D embryos (p < 0.05). The concentration of CoQ10 levels was significantly higher in the pregnant group (p < 0.05). There was no significant correlation between optimal t5 and s2 morphokinetic parameters and CoQ10 levels. However, CoQ10 levels were significantly higher in follicular fluid of embryos which had optimal cc2 (p < 0.05).

CONCLUSION

High follicular fluid CoQ10 level is associated with optimal embryo morphokinetic parameters and higher pregnancy rates.

Clinical background affecting pregnancy outcome following local endometrial injury in infertile patients with repeated implantation failure

Local endometrial injury (LEI) has been performed as a promising medical intervention to improve the pregnancy outcome in infertile women suffering from repeated implantation failure (RIF) in in vitro fertilization-embryo transfer cycles. The effect of LEI, however, remains controversial. The aim of this retrospective study was to identify the subgroups of patients with RIF who benefit from LEI. We compared the clinical parameters between the patients who had had a clinical pregnancy in the subsequent embryo transfer cycle following the LEI cycle (LEI-CP group, n = 94) and those who had resulted in negative pregnancy test (LEI-NP group, n = 114). The female age, basal follicle stimulating hormone concentration, number of past oocyte pickup cycles, and embryos/blastocysts transferred in the past three RIF cycles were significantly (p < 0.047) lower in the LEI-CP group than the LEI-NP group. The prevalence of polycystic ovarian syndrome was significantly (p = 0.0059) higher in the LEI-CP group than in the LEI-NP group. These findings suggest that LEI is most effective to improve the pregnancy outcome in patients undergoing RIF with uncompromised ovarian reserve, particularly in those with polycystic ovarian syndrome.

Do morphokinetic data sets inform pregnancy potential?

Purpose

The aim of this study was to create a model to predict the implantation of transferred embryos based on information contained in the morphokinetic parameters of time-lapse monitoring.

Methods

An analysis of time-lapse recordings of 410 embryos transferred in 343 cycles of in vitro fertilization (IVF) treatment was performed. The study was conducted between June 2012 and November 2014. For each embryo, the following data were collected: the duration of time from the intracytoplasmic sperm injection (ICSI) procedure to further division for two, three, four, and five blastomeres, time intervals between successive divisions, and the level of fragmentation assessed in successive time-points. Principal component analysis (PCA) and logistic regression were used to create a predictive model.

Results

Based on the results of principal component analysis and logistic regression analysis, a predictive equation was constructed. Statistically significant differences (p < 0.001) in the size of the created parameter between the implanted group (the median value: Me = −5.18 and quartiles: Q₁ = −5.61; Q₃ = −4.79) and the non-implanted group (Me = −5.69, Q₁ = −6.34; Q₃ = −5.16) were found. A receiver operating characteristic (ROC) curve constructed for the considered model showed the good quality of this predictive equation. The area under the ROC curve was AUC = 0.70 with a 95 % confidence interval (0.64, 0.75). The presented model has been validated on an independent data set, illustrating that the model is reliable and repeatable.

Conclusions

Morphokinetic parameters contain information useful in the process of creating pregnancy prediction models. However, embryo quality is not the only factor responsible for implantation, and, thus, the power of prediction of the considered model is not as high as in models for blastocyst formation. Nevertheless, as illustrated by the results of this study, the application of advanced data-mining methods in reproductive medicine allows one to create more accurate and useful models.

Morphokinetics of cloned mouse embryos treated with epigenetic drugs and blastocyst prediction

Time-lapse monitoring of somatic cell nuclear transfer (SCNT) embryos may help to predict developmental success and increase birth and embryonic stem cells (ESC) derivation rates. Here, the development of ICSI fertilized embryos and of SCNT embryos, non-treated or treated with either psammaplin A (PsA) or vitamin C (VitC), was monitored, and the ESC derivation rates from the resulting blastocysts were determined. Blastocyst rates were similar among PsA-treated and VitC-treated SCNT embryos and ICSI embryos, but lower for non-treated SCNT embryos. ESC derivation rates were higher in treated SCNT embryos than in non-treated or ICSI embryos. Time-lapse microscopy analysis showed that non-treated SCNT embryos had a delayed development from the second division until compaction, lower number of blastomeres at compaction and longer compaction and cavitation durations compared with ICSI ones. Treatment of SCNT embryos with PsA further increased this delay whereas treatment with VitC slightly reduced it, suggesting that both treatments act through different mechanisms, not necessarily related to their epigenetic effects. Despite these differences, the time of completion of the third division, alone or combined with the duration of compaction and/or the presence of fragmentation, had a strong predictive value for blastocyst formation in all groups. In contrast, we failed to predict ESC derivation success from embryo morphokinetics. Time-lapse technology allows the selection of SCNT embryos with higher developmental potential and could help to increase cloning outcomes. Nonetheless, further studies are needed to find reliable markers for full-term development and ESC derivation success.

New strategy for diagnosing embryo implantation potential by combining proteomics and time-lapse technologies

OBJECTIVE

To develop a diagnostic tool for embryo implantation potential with the use of proteomic fingerprinting combined with time-lapse morphokinetic analysis.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated private in vitro fertilization center.

PATIENT(S)

Seventeen infertile patients undergoing intracytoplasmic sperm injection (ICSI) from our ovum donation program.

INTERVENTION(S)

No patient intervention. We examined morphokinetic data and proteomic data from the spent media of 16 embryos that implanted and 12 embryos that did not implant.

MAIN OUTCOME MEASURE(S)

We analyzed seven proteins in the embryo spent media-SCF, TNFR1, PIGF-1, IFN-α2, IL-6, CXCL13, and GM-CSF-with the use of a bead-based multiplexing technology and combined this data with the exact timing (in hours) of cell cycle duration (cc2), blastomere synchrony (s2), and 5-blastomere cleavage (t5) with the use of an incubator equipped with time-lapse videography.

RESULT(S)

Logistic regression analysis with the use of the forward-step likelihood selection method revealed that the presence/absence of interleukin (IL) 6 and the duration of cc2 were the most relevant embryo features for embryo selection. We combined these two parameters to obtain a hierarchic model that established four categories (A/B/C/D), based on the presence of IL-6 and a cc2 range of 5-12 hours. A direct relationship was observed between the morphologic categories and implantation rates: Those with the presence of IL-6 and 5-12 h cc2 had significantly higher implantation rates.

CONCLUSION(S)

The strategy we report here combines time-lapse and proteome analysis to improve embryo selection while minimizing handling and monitoring by the embryologist. Our results describe the utility of a combined biochemical/morphokinetic approach to select embryos for transfer according to their implantation potential. Clinical validation with larger sample sizes is mandatory to confirm the effectiveness of this initial study.

Quality control and standardization of embryo morphology scoring and viability markers

A so-called 'good-quality embryo' may be defined as an embryo that has the potential to implant into the uterine endometrium and give rise to the birth of a healthy child. A standardized and objective scoring of embryo 'quality' is therefore crucial in the classification and selection of embryos. However, embryo scoring is still being performed mainly via ocular evaluation, which often results in different interpretations of embryo quality. The addition of viability markers, such as measuring gene expression or the uptake/release of metabolites, proteins or RNA/DNA molecules in the culture media, would increase the possibility of standardized measurements. However, no single biomarker has yet been introduced into standard clinical practice, mainly due to the complexity of the techniques and the influence of biological variations and differences in culture conditions. In this paper different methods for the scoring of embryos and the possibility of standardizing and implementing quality control systems are discussed.

Public health implications of a North American publicly funded in vitro fertilization program; lessons to learn

PURPOSE

A retrospective study was conducted to determine trends in practice and outcomes that occurred since the implementation of the publicly funded in vitro fertilization (IVF) and single embryo transfer (SET) program in Quebec, in August, 2010.

METHODS

Data presented was extracted from an advisory report by the Health and Welfare Commissioner, and from a report by the Ministry of Health and Social Services published in June 2014 and October 2013, respectively. This data is publicly available, and was collected from all six private and three public-assisted reproduction centers in Quebec providing IVF services. Data pertains to all IVF cycles performed from the 2009-2010 to 2012-2013 fiscal years.

RESULTS

SET was performed in 71 % of cycles in 2012. The number of children born from IVF was 1057 in 2009-2010 and 1723 in 2012-2013 (p < 0.0001). Multiple birth rates from IVF were 24 % in 2009-2010 (before the program began) and 9.45 % in 2012-2013 (p < 0.0001). The proportions of IVF babies that were premature, that were the result of multiple births, or that required neonatal intensive care unit admission (NICU) all decreased by 35.5 % (p < 0.0001), 55 % (p < 0.0001), and 37 % (p < 0.0001), respectively, from 2009-2010 to 2012-2013. The cost per NICU admission for an IVF baby increased from $19,990 to $28,418 from 2009-2010 to 2011-2012.

CONCLUSION

This first North American publicly funded IVF program with a SET policy shows that such a program contributes substantially to number of births. It has also succeeded in increasing access to treatment and decreasing perinatal morbidity by decreasing multiple birth rates from IVF. A substantial increase in global public health care costs occurred as well.

Morphokinetic parameters of early embryo development via time lapse monitoring and their effect on embryo selection and ICSI outcomes: a prospective cohort study

PURPOSE

To compare the outcomes of embryos selected via time lapse monitoring (TLM) versus those selected with conventional methods of selection in subfertile women undergoing ICSI.

METHODS

The study population (239 women) was classified into two groups, based on the monitoring method used: Group 1 (TLM) and Group 2 (conventional monitoring). Groups were compared according to the clinical and ICSI cycle characteristics and reproductive outcomes, while transfers were performed at day 2 or 3. Subgroup analyses were performed, in women of both groups according to age and clinical parameters, and in embryos of Group 1 based on their cellular events.

RESULTS

There was a statistically significant difference between the two study groups with regard to the outcome parameters, favoring Group 1 and especially in women >40 years of age. No differences were found in subgroup analyses in participants of both groups, regarding the stimulation protocol used, number of the oocytes retrieved and type of subfertility, while in Group 1 the percentages of "in range" cellular events were higher in certain divisions in ages 35-40, non-smokers, and the GnRH-agonist group, and in embryos that resulted in pregnancy.

CONCLUSION

Morphokinetic parameters of early embryo development via TLM are related to the characteristics of subfertile patients and associated with ICSI outcomes.

Diagnosis of human preimplantation embryo viability

BACKGROUND

Transfer of more than a single embryo in an IVF cycle comes with the finite possibility of a multiple gestation. Even a twin pregnancy confers significant risk to both mother and babies. The move to single-embryo transfer for all patients will be greatly facilitated by the ability to quantify embryo viability. Developments in time-lapse incubation systems have provided new insights into the developmental kinetics of the human preimplantation embryo. Advances in molecular methods of chromosomal analysis have created platforms for highly effective screening of biopsied embryos, while noninvasive analysis of embryo physiology reveals more about the embryo than can be determined by morphology alone.

METHODS

Recent developments in time-lapse microscopy, molecular karyotyping and in proteomics and metabolomics have been assessed and presented here in a descriptive review.

RESULTS AND CONCLUSIONS

New algorithms are being created for embryo selection based on their developmental kinetics in culture, and the impact of factors such as patient etiology and treatment are being clarified. Potential links between morphokinetic data and embryo karyotype are being elucidated. The introduction of new molecular methods of determining embryo chromosomal complement is proving to be accurate and reproducible, with the future trending toward CGH arrays or next generation sequencing as a rapid and reliable means of analysis, that should be suitable for each IVF clinic to adopt. A relationship between embryo metabolism and viability is established and is now being considered together with morphokinetic data to create more robust algorithms for embryo selection. Microfluidic devices have the capacity and potential to be used in human IVF clinics for the routine diagnosis of embryo biomarkers.

Time-lapse embryo imaging for improving reproductive outcomes: systematic review and meta-analysis

OBJECTIVE

To identify, appraise and summarize the available evidence regarding the effectiveness and safety of time-lapse embryo monitoring on the main outcomes of assisted reproductive techniques.

METHODS

In this systematic review and meta-analysis, we included only randomized controlled trials (RCTs) comparing time-lapse embryo imaging with standard embryo monitoring. Our primary outcomes were live births (efficacy) and congenital abnormalities (safety). The secondary outcomes were clinical pregnancy, ongoing pregnancy and miscarriage.

RESULTS

Two RCTs were considered eligible, and their data were extracted and included in a meta-analysis. In both studies embryos were transferred at the blastocyst stage. No studies reported rates of live birth or congenital abnormalities. Our estimates were not sufficiently precise to identify whether time-lapse monitoring provided a small benefit, no effect or minor harm on rates of clinical pregnancy (relative risk (RR), 1.05 (95% CI, 0.80-1.38)) or ongoing pregnancy (RR, 1.05 (95% CI, 0.76-1.45)), based on two studies involving 138 women with moderate-quality evidence. Considering the available data, we were unable to determine whether the intervention poses substantial benefit, no effect or substantial harm in the risk of miscarriage (RR, 0.95 (95% CI, 0.30-2.99)), based on two studies involving 76 clinical pregnancies with low-quality evidence.

CONCLUSIONS

Time-lapse embryo imaging is unlikely to have a large effect on the chance of achieving clinical and/or ongoing pregnancy when transferring embryos at the blastocyst stage. More studies are required to improve the quality of the current evidence and also to examine whether this intervention is useful when transferring embryos at the cleavage stage.

Computer-automated time-lapse analysis results correlate with embryo implantation and clinical pregnancy: a blinded, multi-centre study

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.