Selection of embryos for transfer in IVF: ranking embryos based on their implantation potential using morphological scoring

Polygenic embryo screening: quo vadis?

Recently, the use of polygenic risk scores in embryo screening (PGT-P) has been introduced on the premise of reducing polygenic disease risk through embryo selection. However, it has been met with extensive critique: considered "technology-driven" rather than "evidence-based", concerns exist about its validity, utility, ethics, and societal effects. Its scientific foundations and criticisms thus need to be carefully considered. However, seeing as PGT-P is already offered in some settings, further questions need to be addressed, in order to give due diligence to various aspects of PGT-P. By examining the complexities of clinical introduction of PGT-P, we discuss whether PGT-P could be responsibly implemented in the first place, what elements need to be addressed if PGT-P is clinically implemented, and subsequently how counselling and decision-making of its users could be envisaged. By dissecting these elements, we provide an overview of important practical questions of PGT-P and emphasize elements of PGT-P that we think have yet to be given sufficient attention. These questions and elements are for example related to the potential target group, scope, and decision-making possibilities of PGT-P. The aspects we raise are crucial to consider by the scientific community and policy makers for the development of guidelines and/or an ethical framework for PGT-P.

The POPI-Plus tool: prediction model of outcome of pregnancy in in vitro fertilization from a large retrospective cohort

OBJECTIVE

To create a tool that accurately predicts live birth chances after a positive pregnancy test after elective single embryo transfer (ET).

DESIGN

Retrospective cohort.

SETTING

CHUM hospital and Ovo clinic in Montreal, Canada.

PATIENT(S)

Patients with a positive pregnancy test result who underwent their first single ET after in vitro fertilization (IVF) at the CHUM hospital and Ovo clinic in Montreal, Canada, from 2012 to 2016 were selected. A total of 1,995 patients were included in this study.

INTERVENTION(S)

The data from both centers were combined and divided into training (70%, n = 1,398) and validation (30%, n = 597) sets. The predictive model was developed using backward selection method for the following variables: age of patient at egg retrieval; log β-human chorionic gonadotropin (β-hCG) (β-hCG) 1; log β-hCG 2; and IVF treatment type. Moreover, the classification tree, random forest, and neural network models were generated.

MAIN OUTCOME MEASURE(S)

The measured outcomes were live birth (live fetus ≥24 weeks of gestation) and nonviable pregnancies. The performance of all models was evaluated by area under the receiver operating characteristic curve (AUC).

RESULT(S)

Advancing age was negatively correlated with live birth. The odds ratio (OR) of age of patient at the time of egg retrieval was 0.95 (95% confidence interval [CI], 0.91-0.99). The log β-hCG 1 and log β-hCG 2 were positively correlated with live birth in the univariate analysis (OR, 4.15 [95% CI, 3.19-5.39], and OR, 3.84 [95% CI, 2.99-4.93], respectively). The β-hCG 1 level needed for a successful pregnancy was lower in frozen ET and modified natural IVF than in simulated IVF (OR, 0.55 [95% CI, 0.34-0.91], and OR, 0.49 [95% CI, 0.26-0.95], respectively). The best performance in terms of the AUC was the updated logistic model: POPI-Plus. The AUC values were 0.76 (95% CI, 0.73-0.79) and 0.78 (95% CI, 0.74-0.82) for the training and validation data, respectively. The other models (classification tree, random forest, and neural network) also performed adequately, with an AUC of ≥0.7, but remained below POPI-Plus. An open-access calculator was generated and can be found on the website of the University of Montreal on the following link: https://deptobsgyn.umontreal.ca/departement/divisions/medecine-et-biologie-de-la-reproduction/the-popi-plus-tool/.

CONCLUSION(S)

The POPI-Plus tool offers individualized counseling for patients after an initial positive β-hCG test result. Future studies will assess its impact on patient anxiety while awaiting viability ultrasound and perform prospective validation on new patients.

Simultaneous transfer of one good-quality and one poor-quality cleavage stage embryo does not improve pregnancy outcomes

Embryo quality and quantity are key factors that determine the success of IVF-ET. Yet it is still unclear if, for those patients with only one good-quality embryo in an IVF cycle, the inclusion of a poor-quality embryo increases the procedure's success rate. This is a common question for both clinicians and patients in determining their course of treatment. The purpose of this work was to answer this intriguing question in the context of prognosis of patients undergoing fresh cycles with only one good-quality and more than one poor-quality cleavage-stage embryos. To control for confounding effects, we only included patients at similar age, body mass index (BMI), level of basal follicle stimulating hormone (FSH) and endometrial thickness from January 2015 to June 2021. A propensity score-matched analysis was performed to extract the matched pairs. Then we evaluated pregnancy outcome, including the rate of clinical pregnancy, live birth, embryo implantation, early miscarriage, and ectopic pregnancy. We found that the clinical pregnancy rate (34.8 vs. 38.0%, p = 0.553), live birth rate (27.1 vs. 29.9%, p = 0.598), early miscarriage rate (18.1 vs. 9.5%, p = 0.171) and ectopic pregnancy rate (1.3 vs. 1.2%, p = 1.000) did not significantly differ between those two groups, notwithstanding significant difference of the implantation rate (34.8 vs. 21.3%, p <0.001). Our work indicates that, for prognosis patients at approximately 34 years old with only one good-quality embryo, having additional poor-quality embryos does not seem to help to improve ART success rates per intended embryo transfer. In conclusion, we found that simultaneous transfer of one good-quality and one poor-quality cleavage stage embryo does not improve pregnancy outcomes.

Development and validation of deep learning based embryo selection across multiple days of transfer

This work describes the development and validation of a fully automated deep learning model, iDAScore v2.0, for the evaluation of human embryos incubated for 2, 3, and 5 or more days. We trained and evaluated the model on an extensive and diverse dataset including 181,428 embryos from 22 IVF clinics across the world. To discriminate the transferred embryos with known outcome, we show areas under the receiver operating curve ranging from 0.621 to 0.707 depending on the day of transfer. Predictive performance increased over time and showed a strong correlation with morphokinetic parameters. The model's performance is equivalent to the KIDScore D3 model on day 3 embryos while it significantly surpasses the performance of KIDScore D5 v3 on day 5+ embryos. This model provides an analysis of time-lapse sequences without the need for user input, and provides a reliable method for ranking embryos for their likelihood of implantation, at both cleavage and blastocyst stages. This greatly improves embryo grading consistency and saves time compared to traditional embryo evaluation methods.

The Effects of Different Post-thawed Culture Periods on Clinical Outcomes in Frozen Embryo Transfer Cycle

The purpose of this study is to evaluate the effects of different post-thawed culture periods on the clinical outcomes. 9381 frozen embryo transfer (FET) cycles were divided into three groups according to female age: < 35, 35-39, and > 39 years, and two groups depending on post-thawed culture period before transfer: short culture (2-3 h) group (S) and long culture (18-20 h) group (L). According to the increment number of post-thawed embryos, the L group divided into three groups: ≤ 2, one ≤ 2 and the other > 2, and > 2 groups. Pregnancy outcomes included the implantation rate (IR), clinical pregnancy rate (CPR), multiple pregnancy rate (MPR), live birth rate (LBR), and neonatal characteristics. Long post-thawed culture caused a significant increase in the IR, CPR, MPR, and LBR (p = 0.000, 0.004, 0.037, and 0.001; CI = 1.06-1.194, 1.042-1.237, 1.008-1.254, and 1.054-1.245, respectively), and blastomere increment number also had a significant effect on IR, CPR, MPR, and LBR (p = 0.000, 0.000, 0.000, and 0.000, respectively). No significant differences were present in neonatal characteristics between the two post-thawed culture groups. Singleton group had a higher average gestational age and birthweight as well as a lower cesarean section rate, preterm labor rate, and low birthweight rate than twins group. Long post-thawed culture was associated with higher IR, CPR, MPR, and LBR, and transferring a well-developed embryo after long post-thawed culture might be a viable embryo transfer strategy to decrease MPR while maintaining CPR and LBR.

Embryo selection with artificial intelligence: how to evaluate and compare methods?

Embryo selection within in vitro fertilization (IVF) is the process of evaluating qualities of fertilized oocytes (embryos) and selecting the best embryo(s) available within a patient cohort for subsequent transfer or cryopreservation. In recent years, artificial intelligence (AI) has been used extensively to improve and automate the embryo ranking and selection procedure by extracting relevant information from embryo microscopy images. The AI models are evaluated based on their ability to identify the embryo(s) with the highest chance(s) of achieving a successful pregnancy. Whether such evaluations should be based on ranking performance or pregnancy prediction, however, seems to divide studies. As such, a variety of performance metrics are reported, and comparisons between studies are often made on different outcomes and data foundations. Moreover, superiority of AI methods over manual human evaluation is often claimed based on retrospective data, without any mentions of potential bias. In this paper, we provide a technical view on some of the major topics that divide how current AI models are trained, evaluated and compared. We explain and discuss the most common evaluation metrics and relate them to the two separate evaluation objectives, ranking and prediction. We also discuss when and how to compare AI models across studies and explain in detail how a selection bias is inevitable when comparing AI models against current embryo selection practice in retrospective cohort studies.

MicroRNAs secreted by human embryos could be potential biomarkers for clinical outcomes of assisted reproductive technology

Introduction

MicroRNAs (miRNAs) are important regulators of many biological functions, including embryo implantation and development. Recently, it has been reported that miRNAs in biofluids are predictive for physiological and pathological processes.

Objectives

In this study, we aim to investigate whether the miRNAs secreted by human embryos in culture medium can be used as embryonic biomarkers.

Methods

The culture media were prospectively collected from embryos of patients at reproductive medicine center with informed consent. A high-throughput miRNA sequencing method was applied to detect the miRNA profiles in the human embryo culture media. After bioinformatics analysis and screening of differentially expressed miRNAs, quantitative real-time polymerase chain reaction (qRT-PCR) assay was subsequently performed to further confirm the sequencing results with mixed samples. Furthermore, we performed droplet digital PCR (ddPCR) to verify the target miRNAs at single sample level. Receiver operating characteristic (ROC) analyses were performed for differentially expressed miRNAs.

Results

Compared with embryos with failed pregnancy, the embryos with successful pregnancy secreted different miRNA profiles into the culture media, which were predicted to be involved in multiple biological processes. Validated by droplet digital polymerase chain reaction (ddPCR), the expression of hsa-miR-26b-5p and hsa-miR-21-5p in the culture media of cleavage embryos with successful pregnancy was significantly lower than that of embryos with failed pregnancy. Moreover, the Receiver Operating Characteristic (ROC) curve analysis indicated that hsa-miR-26b-5p and hsa-miR-21-5p could serve as potential biomarkers for reproductive outcomes.

Conclusion

Together, our findings highlight the important predictive potential of miRNAs secreted by human embryos in culture media, which is meaningful for non-invasive embryo selection in assisted reproductive technology.

Improving the clinical outcomes by extended culture of day 3 embryos with low blastomere number to blastocyst stage following frozen-thawed embryo transfer

Purpose

This study aimed to investigate whether the extended culture of day 3 (D3) embryos with low blastomere number to blastocyst following frozen–thawed embryo transfer improved the clinical outcomes.

Methods

This was a retrospective study of clinical data of women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles in the Tangdu Hospital. The patients were divided into groups with 4–5, 6, 7–9 and > 9 cells based on the blastomere number of D3 embryos. The clinical outcomes were compared.

Results

In fresh transfer cycles, the implantation and clinical pregnancy rates significantly decreased, while the abortion rate significantly increased in the groups with 4–5 and 6 cells compared with those with 7–9 and > 9 cells. In frozen–thawed transfer cycles, the clinical pregnancy and implantation rates for a single blastocyst transfer cycle showed no significant differences in the groups with 4–5 and 6 cells compared with those with 7–9 and > 9 cells. However, the abortion rate was significantly higher in the group with 4–5 cells than in that with 7–9 and > 9 cells. In the double blastocyst transfer cycle, the clinical pregnancy rate showed no significant differences among the groups with 4–5, 6, and 7–9 cells.

Conclusion

The implantation and clinical pregnancy rates of D3 embryos with 6 cells significantly decreased; these embryos were not considered as high-quality embryos. Extended culture of D3 embryos with ≤ 6 blastomeres to blastocysts, particularly 6-cell embryos, resulted in a similar clinical pregnancy rate as that of blastocysts derived from D3 embryos with ≥ 7 blastomeres.

Mining of variables from embryo morphokinetics, blastocyst's morphology and patient parameters: an approach to predict the live birth in the assisted reproduction service

Based on growing demand for assisted reproduction technology, improved predictive models are required to optimize in vitro fertilization/intracytoplasmatic sperm injection strategies, prioritizing single embryo transfer. There are still several obstacles to overcome for the purpose of improving assisted reproductive success, such as intra- and inter-observer subjectivity in embryonic selection, high occurrence of multiple pregnancies, maternal and neonatal complications. Here, we compare studies that used several variables that impact the success of assisted reproduction, such as blastocyst morphology and morphokinetic aspects of embryo development as well as characteristics of the patients submitted to assisted reproduction, in order to predict embryo quality, implantation or live birth. Thereby, we emphasize the proposal of an artificial intelligence-based platform for a more objective method to predict live birth.

The Annual Capri Workshop Group, Albertini DF, Crosignani P, Dumoulin J, Evers JLH, Leridon H, Mastenbroek S, Painter R, Pinborg A, Somigliana E, Baird DT, Glasier A, La Vecchia C, Albertini DF, Crosignani P, Dumoulin J, Evers JLH, Leridon H, Mastenbroek S, Painter R, Pinborg A, Somigliana E, Baird DT, Glasier A, La Vecchia C. IVF, from the past to the future: the inheritance of the Capri Workshop Group

Today IVF use is booming all over the world and has even started to play a role in demographic analyses. Prognosis-adjusted estimates suggest that up to two-thirds of couples could achieve a live birth. However, the scenario is less exciting in reality. Discontinuation during the cycles is common, and age and ovarian response continue to be crucial in modulating this rate of success. A growing interest is now given to the risk of abuses and in particular to overtreatment and to prescriptions of useless, if not harmful, expensive additional treatments ('add-ons'). A more rational, evidence-based and wise approach is needed. From a scientific perspective, several obscure aspects remain and warrant future investigations. Of particular interest are the neglected role of sperm selection, the potential adult implications of early embryo life in vitro and the issue of sustainability.

Improvement instead of stability in embryo quality between day 3-5: A possible extra predictor for blastocyst selection

OBJECTIVE

The aim of this study was to evaluate the predictive value of the dynamic morphological development process between cleavage-stage and blastocyst-stage embryos.

STUDY DESIGN

A retrospective study was executed between 2015 and 2017 at Ghent University Hospital. A total of 996 first fresh IVF/ICSI cycles resulting in a single embryo transfer on day 5 were included. Embryos were scored on day 3 and day 5 as excellent, good, moderate or poor based on Alpha/ESHRE guidelines and Gardner and Schoolcraft scoring-system. If embryos changed category between day 3 and 5, the number of steps (between excellent; good; moderate; poor) in positive and negative direction was expressed.

RESULTS

On day 5, the ongoing pregnancy rate (OPR) of excellent embryos was 37.4 %. Univariate analyses showed that on day 5, both a higher cell stage, better inner cell mass and better trophectoderm were significantly associated with an ongoing pregnancy. In case of deterioration in quality of individual embryos between day 3 and day 5, the OPR was significantly lower. Conversely, improvement of embryo quality between day 3 and day 5 showed higher ongoing pregnancy rates (overall OPR of good day-3 embryos improving to excellent day-5 embryos: 30 %; moderate day 3 to excellent day 5: 50 %; poor day 3 to excellent day 5: 42 %; poor day 3 to good day 5: 20 %; poor day 3 to moderate day 5: 16 %). When embryos improved from poor on day 3 to excellent day 5 the OPR was significantly higher in comparison with embryos that did not change in quality scoring during development (steady embryos) (OR: 1.785, p < 0.05).

CONCLUSION

Our results suggest that it is more likely to achieve an ongoing pregnancy when transferring an embryo that has improved in quality between days 3 and 5 as opposed to one that has remained stable.

High-quality human preimplantation embryos stimulate endometrial stromal cell migration via secretion of microRNA hsa-miR-320a

STUDY QUESTION

How do high-quality human preimplantation embryos influence the endometrium to promote their own implantation?

SUMMARY ANSWER

High-quality human preimplantation embryos secrete a specific microRNA (miRNA), hsa-miR-320a, which promotes migration of human endometrial stromal cells (hESCs).

WHAT IS KNOWN ALREADY

We have previously shown that high-quality human preimplantation embryos excrete unknown factors that influence migration of hESCs.

STUDY DESIGN, SIZE, DURATION

Embryo excreted miRNAs, specifically those excreted by high-quality embryos, were identified and their effect on hESCs was determined by measuring the migration capacity and gene expression patterns of primary isolated hESCs.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Embryo conditioned medium (ECM) from routine ICSI procedures was used to identify embryo excreted miRNAs. miRNome analyses were performed on ECM from individually cultured embryos with high morphological quality, with low morphological quality or empty control medium. MiRNA mimics and inhibitors were then used to further study the effect of miRNAs of interest on migration and gene expression of hESCs. Migration assays were performed using hESCs that were obtained from endometrial biopsies performed on hysterectomy specimens from women that received surgery for spotting due to a niche in a cesarean section scar.

MAIN RESULTS AND THE ROLE OF CHANCE

By using miRNA mimics and inhibitors, we showed that hsa-miR-320a alone can stimulate migration of decidualized hESCs, accurately resembling the response typically triggered only by high-quality embryos. Transcriptome analysis further demonstrated that this effect is very likely mediated via altered expression of genes involved in cell adhesion and cytoskeleton organization.

LIMITATIONS, REASONS FOR CAUTION

The effect of hsa-miR-320a on hESCs was measured in vitro. Further studies on the in vivo effect of hsa-miR-320a are warranted.

WIDER IMPLICATIONS OF THE FINDINGS

Implantation failure is one of the major success limiting factors in human reproduction. By secreting hsa-miR-320a, high-quality human preimplantation embryos directly influence hESCs, most likely to prime the endometrium at the implantation site for successful implantation. Together, our results indicate that hsa-miR-320a may be a promising target to further increase success rates in assisted reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Amsterdam University Medical Centers and the Amsterdam Reproduction & Development Research Institute. R.P.B., G.H. and S.M. have a patent on the use of hsa-miR-320a in assisted reproduction treatments pending.

TRIAL REGISTRATION NUMBER

N/A.

Correlation between morphokinetic parameters and standard morphological assessment: what can we predict from early embryo development? A time-lapse-based experiment with 2085 blastocysts

Objectives:

To evaluate the association between morphology grading and morphokinetic parameters in blastocyst stage embryos cultured in a time-lapse system.

Methods:

This retrospective cohort study included patients offered fertility treatment with autologous oocytes in our clinic between October 2017 and May 2019 using a time-lapse system. The embryos were morphologically graded according to the criteria developed by Gardner and Schoolcraft and their morphokinetic parameters were recorded.

Results:

Our results indicated that the time of pronuclei fading (tPNf), time to cleavage into two (t2), four (t4), and eight (t8) cells, and time to start of blastulation (tB) were significantly different according to the morphological quality of the blastocysts formed. In the early development stage, tPNf, t2 and t4 differed between good (AA, AB, BA, BB) and poor (CC) quality potential blastocysts. The 8-cell stage time separated embryos graded as AA blastocysts in terms of morphology from embryos graded as BB. Earlier tB correlated with higher quality embryos (AA, AB, BA).

Conclusion:

Our results showed that the first kinetic parameters (tPNf, t2, and t4) distinguished top-graded from low-graded blastocysts. Between top-graded blastocysts, t8 separated BB blastocysts from AA blastocysts. And finally, tB also told apart BB blastocysts from AA, AB, and BA blastocysts. These time-related parameters may be applied even in centers without time-lapse systems.

Between innovation and precaution: how did offspring safety considerations play a role in strategies of introducing new reproductive techniques?

The field of reproductive medicine has been criticized for introducing ARTs without systematic research on possible safety risks and for failing to meet the standards of evidence-based innovation held elsewhere in medicine. In this paper, firstly, we ask whether ‘responsible innovation’ has been a concern for the field, and if so, how it has understood the practical implications of this idea for the development and introduction of potentially risky new ARTs. Secondly, we consider whether the field has indeed fallen short of its responsibilities in this respect, and if so, how things can be improved. To answer these questions, we present three case studies involving the introduction of a new reproductive technology: ICSI, preimplantation genetic testing and mitochondrial replacement therapy. As a framework for analyzing these cases, we used Per Sandin’s account of the four dimensions of dealing with risks (threat, uncertainty, action, command) that are central to debates about the possible role of the so-called precautionary principle. We conclude that, although offspring safety concerns have been on the agenda of the debate about bringing the relevant technologies to the clinic, systematic safety and effectiveness studies were not always conducted. As professionals in assisted reproduction have a responsibility to take account of the welfare of the children they are creating, we suggest a policy of proceeding with systematic caution. Legal measures may be needed to ensure that professional guidance is followed in practice. Finally, an open question concerns the threshold for acceptable risk in the context of introducing new ARTs. Multiple stakeholders, including professional societies and patient organizations, should have a role in the urgent debate about this.

A Preclinical Evaluation towards the Clinical Application of Oxygen Consumption Measurement by CERMs by a Mouse Chimera Model

We have developed an automated device for the measurement of oxygen consumption rate (OCR) called Chip-sensing Embryo Respiratory Measurement system (CERMs). To verify the safety and the significance of the OCR measurement by CERMs, we conducted comprehensive tests using a mouse model prior to clinical trials in a human in vitro fertilization (IVF) program. Embryo transfer revealed that the OCR measured by CERMs did not compromise the full-term development of mice or their future fertility, and was positively correlated with adenosine triphosphate (ATP) production and the mitochondrial membrane potential (ΔΨm), thereby indirectly reflecting mitochondrial oxidative phosphorylation (OXPHOS) activity. We demonstrated that the OCR is independent of embryo morphology (the size) and number of mitochondria (mitochondrial DNA copy number). The OCR correlated with the total cell numbers, whereas the inner cell mass (ICM) cell numbers and the fetal developmental rate were not. Thus, the OCR may serve as an indicator of the numbers of trophectoderm (TE) cells, rather than number or quality of ICM cells. However, implantation ability was neither correlated with the OCR, nor the embryo size in this model. This can probably be attributed to the limitation that chimeric embryos contain non-physiological high TE cells counts that are beneficial for implantation. CERMs can be safely employed in clinical IVF owing to it being a safe, highly effective, non-invasive, accurate, and quantitative tool for OCR measurement. Utilization of CERMs for clinical testing of human embryos would provide further insights into the nature of oxidative metabolism and embryonic viability.

External validation of a prediction model to select the best day-three embryo for transfer in in vitro fertilization or intracytoplasmatic sperm injection procedures

OBJECTIVE

To evaluate the multivariate embryo selection model by van Loendersloot et al. (2014) (VL) in a different geographical context.

DESIGN

This is a retrospective external validation study of a 5-year cohort of women undergoing in vitro fertilization or intracytoplasmatic sperm injection.

SETTING

Two outpatient fertility clinics.

PATIENT(S)

A total of 1,197 women who underwent 1,610 fresh in vitro fertilization or intracytoplasmatic sperm injection cycles with single embryo transfer were included.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The area under the receiver operating characteristics curve for diagnostic efficacy was used to assess the discriminative value of the model. Calibration for testing the validity of the VL model was performed using the Hosmer-Lemeshow goodness-of-fit test and a calibration plot.

RESULT(S)

Three hundred thirty-three patients (21%) achieved a viable pregnancy of at least 11 weeks. The area under the receiver operating characteristics curve using the VL model was 0.68. No significant difference between the predicted implantation rate and the observed implantation rates was showed using the Hosmer-Lemeshow (X²= 6.70). The calibration plot showed an intercept of the regression line of 0.34 and the estimated slope was 0.72.

CONCLUSION

The investigated VL model was able to distinguish between higher and lower implantation potential of embryos in our clinical setting.

Artificial Intelligence-Based Grading Quality of Bovine Blastocyst Digital Images: Direct Capture with Juxtaposed Lenses of Smartphone Camera and Stereomicroscope Ocular Lens

In this study, we developed an online graphical and intuitive interface connected to a server aiming to facilitate professional access worldwide to those facing problems with bovine blastocysts classification. The interface Blasto3Q, where 3Q refers to the three qualities of the blastocyst grading, contains a description of 24 variables that were extracted from the image of the blastocyst and analyzed by three Artificial Neural Networks (ANNs) that classify the same loaded image. The same embryo (i.e., the biological specimen) was submitted to digital image capture by the control group (inverted microscope with 40× magnification) and the experimental group (stereomicroscope with maximum of magnification plus 4× zoom from the cell phone camera). The images obtained from the control and experimental groups were uploaded on Blasto3Q. Each image from both sources was evaluated for segmentation and submitted (only if it could be properly or partially segmented) for automatic quality grade classification by the three ANNs of the Blasto3Q program. Adjustments on the software program through the use of scaling algorithm software were performed to ensure the proper search and segmentation of the embryo in the raw images when they were captured by the smartphone, since this source produced small embryo images compared with those from the inverted microscope. With this new program, 77.8% of the images from smartphones were successfully segmented and from those, 85.7% were evaluated by the Blasto3Q in agreement with the control group.

Making IVF more effective through the evolution of prediction models: is prognosis the missing piece of the puzzle?

Assisted reproductive technology has evolved tremendously since the emergence of in vitro fertilization (IVF). In the course of the recent decade, there have been significant efforts in order to minimize multiple gestations, while improving percentages of singleton pregnancies and offering individualized services in IVF, in line with the trend of personalized medicine. Patients as well as clinicians and the entire IVF team benefit majorly from 'knowing what to expect' from an IVF cycle. Hereby, the question that has emerged is to what extent prognosis could facilitate toward the achievement of the above goal. In the current review, we present prediction models based on patients' characteristics and IVF data, as well as models based on embryo morphology and biomarkers during culture shaping a complication free and cost-effective personalized treatment. The starting point for the implementation of prediction models was initiated by the aspiration of moving toward optimal practice. Thus, prediction models could serve as useful tools that could safely set the expectations involved during this journey guiding and making IVF treatment more effective. The aim and scope of this review is to thoroughly present the evolution and contribution of prediction models toward an efficient IVF treatment.

ABBREVIATIONS

IVF: In vitro fertilization; ART: assisted reproduction techniques; BMI: body mass index; OHSS: ovarian hyperstimulation syndrome; eSET: elective single embryo transfer; ESHRE: European Society of Human Reproduction and Embryology; mtDNA: mitochondrial DNA; nDNA: nuclear DNA; ICSI: intracytoplasmic sperm injection; MBR: multiple birth rates; LBR: live birth rates; SART: Society for Assisted Reproductive Technology Clinic Outcome Reporting System; AFC: antral follicle count; GnRH: gonadotrophin releasing hormone; FSH: follicle stimulating hormone; LH: luteinizing hormone; AMH: anti-Müllerian hormone; DHEA: dehydroepiandrosterone; PCOS: polycystic ovarian syndrome; NPCOS: non-polycystic ovarian syndrome; CE: cost-effectiveness; CC: clomiphene citrate; ORT: ovarian reserve test; EU: embryo-uterus; DET: double embryo transfer; CES: Cumulative Embryo Score; GES: Graduated Embryo Score; CSS: Combined Scoring System; MSEQ: Mean Score of Embryo Quality; IMC: integrated morphology cleavage; EFNB2: ephrin-B2; CAMK1D: calcium/calmodulin-dependent protein kinase 1D; GSTA4: glutathione S-transferase alpha 4; GSR: glutathione reductase; PGR: progesterone receptor; AMHR2: anti-Müllerian hormone receptor 2; LIF: leukemia inhibitory factor; sHLA-G: soluble human leukocyte antigen G.

High-quality human preimplantation embryos actively influence endometrial stromal cell migration

Purpose

The purpose of this paper is to study whether human preimplantation embryos regulate endometrial stromal cell (hESC) migration.

Methods

Primary hESCs were isolated from fertile patients undergoing hysterectomy for benign conditions (uterine scar niche n = 3, dysmenorrhea n = 2; no hormonal treatment). Migration and proliferation assays were performed by culturing decidualized or non-decidualized hESCs in the presence of embryo conditioned medium (ECM) from high-quality embryos (fragmentation ≤ 20%) or from low-quality embryos (fragmentation > 20%) or in non-conditioned medium from the same dishes (control). ECM samples from 425 individually cultured human embryos were used in this study.

Results

ECM from high-quality embryos, i.e., with a low percentage of fragmentation, actively stimulated decidualized hESC migration (p < 0.001). This effect was consistent throughout embryonic development from cleavage stage embryos with 2–7 cells (high quality vs. control; p = 0.036), 8–18 cells (high quality vs. control; p < 0.001) to morulae (high quality vs. control; p = 0.003). Additionally, linear regression analysis showed that hESC migration was influenced by embryo quality (fragmentation, β − 0.299; p = 0.025) and not developmental stage (cell number, β 0.177; p = 0.176) or maternal age (β − 0.036; p = 0.78). Opposite to decidualized hESCs, the migration response of non-decidualized hESCs was inhibited by ECM from high-quality embryos (p = 0.019). ECM from low-quality embryos, i.e., with a high percentage of fragmentation, did not cause an altered migration response in decidualized hESCs (p = 0.860) or non-decidualized hESCs (p = 0.986). Furthermore, ECM of both high- and low-quality human embryos did not influence the number of proliferating cells (p = 0.375) and the cell cycle time (p = 0.297) of non-decidualized or decidualized hESCs.

Conclusion

This study reveals a mechanism by which high-quality human preimplantation embryos actively interact with the endometrium to increase their chances of successful implantation.

Electronic supplementary material

The online version of this article (10.1007/s10815-017-1107-z) contains supplementary material, which is available to authorized users.

The addition of a low-quality embryo as part of a fresh day 3 double embryo transfer does not improve ongoing pregnancy rates

STUDY QUESTION

Does the addition of a low-quality embryo in fresh Day 3 double embryo transfer (DET) affect the ongoing pregnancy rate (OPR) and multiple gestation rate in patients with only one or no high-quality embryos available?

SUMMARY ANSWER

In patients with only one- or no high-quality embryo available, the addition of a low-quality embryo in fresh Day 3 DET does not improve the OPR but increases multiple gestation rates in fresh DET.

WHAT IS KNOWN ALREADY

Pregnancy rates after DET are considered to be higher compared to single embryo transfer (SET) when analyzed per first embryo transfer only. However, these conclusions are based on RCTs in which mostly patients with two or more high-quality embryos were included, and can therefore not be applied to patients with only one or no high-quality embryo available. This is particularly relevant since it has been suggested that low-quality embryos could impair the implantation of simultaneously transferred embryos by paracrine signaling. Hence, we investigated in patients with only one or no high-quality embryo available whether the addition of a low-quality embryo in DET affects the OPR, multiple gestation rate and miscarriage rate.

STUDY DESIGN SIZE DURATION

This was a retrospective cohort study of 5050 patients receiving 7252 fresh embryo transfers on Day 3 after fertilization in IVF/ICSI cycles from 2012 to 2015 in two academic hospitals.

PARTICIPANTS/MATERIALS SETTING METHODS

We included all women that received fresh SET or DET with any combination of high-quality embryos (7, 8 or 9 blastomeres, with equal to or <20% fragmentation) or low-quality embryos (all other embryos). Outcomes were OPR (primary outcome, defined as a positive fetal heartbeat by transvaginal ultrasound at least 10 weeks after oocyte retrieval), miscarriage rate and multiple gestation rate. We used a generalized estimating equations model adjusting for maternal age, number of oocytes retrieved, center of treatment and the interaction between maternal age and number of oocytes retrieved. Other baseline characteristics, including infertility diagnosis, fertilization method and the number of consecutive fresh embryo transfers per patient, did not contribute significantly to the GEE model and were therefore excluded, and not adjusted for.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to SET with one high-quality embryo, DET with two high-quality embryos resulted in a higher OPR (adjusted odds ratio (OR) 1.38, 95% CI 1.14-1.67), while DET with one high- and one low-quality embryo resulted in a lower OPR (adjusted OR 0.65, 95% CI 0.49-0.90). However, SET in patients with only one high-quality embryo available resulted in a lower OPR compared to SET in patients with two or more high-quality embryos available (adjusted OR 0.52, 95% CI 0.39-0.70). After adjusting for this confounding factor, we found that both DET with two high-quality embryos (adjusted OR 0.99, 95% CI 0.74-1.31) and DET with one high- and one low-quality embryo (adjusted OR 0.78, 95% CI 0.47-1.27) resulted in a not significantly different OPR compared to SET with one high-quality embryo. If only low-quality embryos were available, DET did not increase the OPR as compared to SET with one low-quality embryo (adjusted OR 0.84, 95% CI 0.55-1.28). Multiple gestation rates were higher in all DET groups compared to SET (DET with ≥1 high-quality embryo(s) compared to SET with one high-quality embryo; DET with two low-quality embryos compared to SET with one low-quality embryo; all comparisons P < 0.001). Miscarriage rates were not different in all DET groups compared to SET (DET with ≥1 high-quality embryo(s) compared to SET with one high-quality embryo; DET with two low-quality embryos compared to SET with one low-quality embryo; all comparisons P > 0.05).

LIMITATIONS REASONS FOR CAUTION

Limitations to this study include the retrospective design and possible bias between study groups related to embryo transfer policies between 2012 and 2015. Consequently, we may have underestimated pregnancy chances in all DET groups. Furthermore, the OPR was calculated as a percentage of the number of fresh embryo transfers in each study group, and not the total number of started IVF/ICSI cycles. Therefore, the reported pregnancy outcomes may not truly reflect the pregnancy chances of couples at the start of treatment. A possible confounding effect of maternal age in our study is acknowledged but we could not compare clinical outcomes in different age groups separately owing to small sample sizes. Analysis of pregnancy outcomes in lower prognosis patients (higher maternal age, fewer oocytes retrieved) separately is an avenue for future research.

WIDER IMPLICATIONS OF THE FINDINGS

The decision to perform DET rather than SET in order to increase the OPR per fresh embryo transfer seems not to be justified for those patients with only one or no high-quality embryo(s) available. However, owing to the limitations of this study, prospective RCTs are needed that specifically investigate pregnancy outcomes in patients with only one or no high-quality embryo(s) available in SET and DET.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by a grant from the joint Amsterdam Reproduction & Development Institute of the Academic Medical Center and VU University Medical Center (www.amsterdam-reproduction-and-development.org). The authors have no conflicts of interest to declare.

Predicting pregnancy rate following multiple embryo transfers using algorithms developed through static image analysis

Single-embryo image assessment involves a high degree of inaccuracy because of the imprecise labelling of the transferred embryo images. In this study, we considered the entire transfer cycle to predict the implantation potential of embryos, and propose a novel algorithm based on a combination of local binary pattern texture feature and Adaboost classifiers to predict pregnancy rate. The first step of the proposed method was to extract the features of the embryo images using the local binary pattern operator. After this, multiple embryo images in a transfer cycle were considered as one entity, and the pregnancy rate was predicted using three classifiers: the Real Adaboost, Gentle Adaboost, and Modest Adaboost. Finally, the pregnancy rate was determined via the majority vote rule based on classification results of the three Adaboost classifiers. The proposed algorithm was verified to have a good predictive performance and may assist the embryologist and clinician to select embryos to transfer and in turn improve pregnancy rate.

Development of a new clinically applicable device for embryo evaluation which measures embryo oxygen consumption

STUDY QUESTION

Does a new system-the chip-sensing embryo respiration monitoring system (CERMs)-enable evaluation of embryo viability for potential application in a clinical IVF setting?

SUMMARY ANSWER

The system enabled the oxygen consumption rate of spheroids, bovine embryos and frozen-thawed human embryos to be measured, and this rate corresponded to the developmental potential of embryos.

WHAT IS ALREADY KNOWN

To date, no reliable and clinically suitable objective evaluation methods for embryos are available, which circumvent the differences in inter-observer subjective view. Existing systems such as the scanning electrochemical microscopy (SECM) technique, which enables the measurement of oxygen consumption rate in embryos, need improvement in usability before they can be applied to a clinical setting.

STUDY DESIGN, SIZE, DURATION

This is a prospective original research study. The feasibility of measuring the oxygen consumption rate was assessed using CERMs for 9 spheroids, 9 bovine embryos and 30 redundant frozen-thawed human embryos. The endpoints for the study were whether CERMs could detect a dissolved oxygen gradient with high sensitivity, had comparable accuracy to the SECM measuring system with improved usability, and could predict the development of an embryo to a blastocyst by measuring the oxygen consumption rate. The relationship between the oxygen consumption rate and standard morphological evaluation was also examined.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We developed a new CERMs, which enables the oxygen consumption rate to be measured automatically using an electrochemical method. The device was initially used for measuring a dissolved oxygen concentration gradient in order to calculate oxygen consumption rate using nine spheroids. Next, we evaluated data correlation between the CERMs and the SECM measuring systems using nine bovine embryos. Finally, the oxygen consumption rates of 30 human embryos, which were frozen-thawed on 2nd day after fertilization, were measured by CERMs at 6, 24, 48, 72 and 96 h after thawing with standard morphological evaluation. Furthermore, the developed blastocysts were scored using the blastocyst quality score (BQS), and the correlation with oxygen consumption rate was also assessed.

MAIN RESULTS AND THE ROLE OF CHANCE

The device enabled the oxygen consumption rate of an embryo to be measured automatically within a minute. The oxygen concentration gradient profile showed excellent linearity in a distance-dependent change. A close correlation in the oxygen consumption rates of bovine embryos was observed between the SECM measuring system and CERMs, with a determination coefficient of 0.8203 (P = 0.0008). Oxygen consumption rates of human embryos that have reached the blastocyst stage were significantly higher than those of arrested embryos at 48, 72 and 96 h after thawing (P = 0.039, 0.004 and 0.049, respectively). Thus, in vitro development of frozen-thawed human embryos to the blastocyst stage would be predicted at 48 h after thawing (day 4) by measuring the oxygen consumption using CERMs. Although a positive linear relationship between BQS and the oxygen consumption rate was observed [the determination coefficient was R(2) = 0.6537 (P = 0.008)], two blastocysts exhibited low oxygen consumption rates considering their relatively high BQS. This suggests that morphology and metabolism in human embryos might not correlate consistently.

LIMITATIONS, REASONS FOR CAUTION

Transfer of the embryo and pregnancy evaluation was not performed. Thus, a correlation between oxygen consumption and the in vivo viability of embryos remains unknown. Clinical trials, including embryo transfer, would be desirable to determine a threshold value to elect clinically relevant, quality embryos for transfer. We utilized frozen-thawed human embryos in this study. The effect of these manipulations on the respiratory activity of the embryo is also unknown.

WIDER IMPLICATIONS OF THE FINDINGS

Selection of quality embryos, especially in a single embryo transfer cycle, by CERMs may have an impact on obtaining better clinical outcomes, albeit with clinical trials being required. Furthermore, the early determination of quality embryos by CERMs may enable the omission of long-term in vitro embryo culture to the blastocyst stage. CERMs is scalable technology that can be integrated into incubators and/or other embryo evaluation systems, such as the time-lapse systems, due to its chip-based architecture. Thus, CERMS would enable automatic measurement of oxygen consumption, under 5% CO2, in the near future, in order to reduce oxidative stress from exposure to atmospheric air.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the Health and Labor Sciences Research Grant (H24-Hisaichiiki-Shitei-016). The authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

Not applicable.

Methods for assessing the quality of mammalian embryos: How far we are from the gold standard?

Morphological embryo classification is of great importance for many laboratory techniques, from basic research to the ones applied to assisted reproductive technology. However, the standard classification method for both human and cattle embryos, is based on quality parameters that reflect the overall morphological quality of the embryo in cattle, or the quality of the individual embryonic structures, more relevant in human embryo classification. This assessment method is biased by the subjectivity of the evaluator and even though several guidelines exist to standardize the classification, it is not a method capable of giving reliable and trustworthy results. Latest approaches for the improvement of quality assessment include the use of data from cellular metabolism, a new morphological grading system, development kinetics and cleavage symmetry, embryo cell biopsy followed by pre-implantation genetic diagnosis, zona pellucida birefringence, ion release by the embryo cells and so forth. Nowadays there exists a great need for evaluation methods that are practical and non-invasive while being accurate and objective. A method along these lines would be of great importance to embryo evaluation by embryologists, clinicians and other professionals who work with assisted reproductive technology. Several techniques shows promising results in this sense, one being the use of digital images of the embryo as basis for features extraction and classification by means of artificial intelligence techniques (as genetic algorithms and artificial neural networks). This process has the potential to become an accurate and objective standard for embryo quality assessment.

Selecting the embryo with the highest implantation potential using a data mining based prediction model

BACKGROUND

Embryo selection has been based on developmental and morphological characteristics. However, the presence of an important intra-and inter-observer variability of standard scoring system (SSS) has been reported. A computer-assisted scoring system (CASS) has the potential to overcome most of these disadvantages associated with the SSS. The aims of this study were to construct a prediction model, with data mining approaches, and compare the predictive performance of models in SSS and CASS and to evaluate whether using the prediction model would impact the selection of the embryo for transfer.

METHODS

A total of 871 single transferred embryos between 2008 and 2013 were included and evaluated with two scoring systems: SSS and CASS. Prediction models were developed using multivariable logistic regression (LR) and multivariate adaptive regression splines (MARS). The prediction models were externally validated with a test set of 109 single transfers between January and June 2014. Area under the curve (AUC) in training data and validation data was compared to determine the utility of the models.

RESULTS

In SSS models, the AUC declined significantly from training data to validation data (p < 0.05). No significant difference was detected in CASS derived models. Two final prediction models derived from CASS were obtained using LR and MARS, which showed moderate discriminative capacity (c-statistic 0.64 and 0.69 respectively) on validation data.

CONCLUSIONS

The study showed that the introduction of CASS improved the generalizability of the prediction models, and the combination of computer-assisted scoring system with data mining based predictive modeling is a promising approach to improve the selection of embryo with the highest implantation potential.

Developmentally delayed cleavage-stage embryos maintain comparable implantation rates in frozen embryo transfers

PURPOSE

In fresh IVF cycles, embryos reaching the eight-cell stage on day 3 of development are thought to have a higher chance of implantation than those reaching this stage on day 4. To determine whether this difference persists after cryopreservation, we compared pregnancy and implantation rates between frozen embryo transfer (FET) cycles using delayed cleavage-stage embryos (cryopreserved day 4) and normal cleavage-stage embryos (cryopreserved day 3).

METHODS

Participants underwent FET between 2008 and 2012 using embryos cryopreserved on either day 3 (n = 76) or day 4 (n = 48), depending on the length of time needed to achieve the eight-cell stage. All embryos, regardless of day of cryopreservation, were thawed and transferred on the 4th day of vaginal progesterone following endometrial preparation with oral estradiol. Chi-square and Mann-Whitney U tests were used to compare patient demographics and cycle outcomes.

RESULTS

More women in the day 4 group had diminished ovarian reserve (44 vs 16 %, p = 0.003). Pregnancy outcomes in preceding fresh cycles were not different between the two groups. Pregnancy, implantation, and live birth rates following FET did not differ between the day 3 and day 4 groups.

CONCLUSIONS

This is the first study to address outcomes using day 3 versus day 4 cryopreserved embryos. Despite a higher prevalence of diminished ovarian reserve (DOR) in the day 4 group, delayed cleavage-stage embryos utilized in FET cycles performed as well as embryos growing at the normal rate, suggesting delayed embryo development does not affect embryo implantation as long as endometrial synchrony is maintained.

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.

Does sperm origin affect embryo morphokinetic parameters?

PURPOSE

The purpose of our study was to use time-lapse in order to evaluate the impact of sperm origin (fresh ejaculate or surgically retrieved) on embryo morphokinetic parameters and clinical outcome in intracytoplasmic sperm injection (ICSI) cycles.

METHODS

This retrospective monocentric study was conducted in 485 unselected couples undergoing 604 ICSI cycles with embryo culture in the Embryoscope®. Among them, 445 couples underwent ICSI cycle with fresh ejaculated sperm and 40 with surgically retrieved sperm (26 with testicular sperm and 14 with epididymal sperm). Embryo morphokinetic parameters and clinical cycle outcome were compared between fresh ejaculated sperm and surgically retrieved sperm. A subgroup analysis was also conducted between testicular and epididymal sperm ICSI cycles.

RESULTS

Clinical outcome was comparable between groups according to sperm origin. Although most early morphokinetic parameters were comparable between ejaculated and surgical sperm groups, a few parameters were significantly different between both groups, but with a considerable overlap in their distribution. Late cellular events occurred significantly later in the surgical sperm group than in the ejaculated sperm group.

CONCLUSIONS

Morphokinetic analysis did not allow us to identify clinically relevant differences between fresh ejaculate and surgically retrieved sperm groups. Further studies are needed, especially concerning the relationship between sperm origin and late morphokinetic parameters, such as blastocyst development.

Choosing the best embryo by time lapse versus standard morphology

Within the past few years the morphological evaluation of in vitro fertilized embryos has been extended to include continuous surveillance, enabled by the introduction of time-lapse incubators developed specifically for IVF treatment. As a result time-lapse monitoring has been implemented in many clinics worldwide. The proposed benefits compared with culture in a standard incubator and fixed time-point evaluation are uninterrupted culture, a flexible workflow in the laboratory, and improved embryo selection. The latter is based on the reasonable assumption that more frequent observations will provide substantially more information on the relationship between development, timing, and embryo viability. Several retrospective studies have confirmed a relationship between time-lapse parameters and embryo viability evaluated by developmental competence, aneuploidy, and clinical pregnancy. Furthermore a much anticipated randomized study has shown improved pregnancy rates (PRs) after culture in a time-lapse incubator combined with selection using a hierarchical time-lapse selection model. At present this is the only randomized study on possible benefits of time lapse in human embryology. Strict evidence may still seem too weak to introduce time lapse in routine clinical setting. This aim of this review is therefore to perform a balanced discussion of the evidence for time-lapse monitoring.

Time-lapse in the IVF-lab: how should we assess potential benefit?

Time-lapse imaging of embryos has been widely introduced to fertility laboratories worldwide with the aim of identifying the best quality embryos to transfer that will ultimately improve IVF success rates. In this opinion paper, we explore the lack of evidence of benefit of this novel intervention, analyse the methodological flaws of current studies, offer ideal study designs that assess the various features of time-lapse imaging, and discuss forthcoming studies. In particular, we emphasize the ethical aspects of hastily adopting a costly technology without current high level evidence of improved live birth rates, safety and cost effectiveness.