Search

Study Question: Is a commercially available embryo assessment algorithm for early embryo evaluation based on the automatic annotation of morphokinetic timings a useful tool for embryo selection in IVF cycles?, Summary Answer: The classification provided by the algorithm was shown to be significantly predictive, especially when combined with conventional morphological evaluation, for development to blastocyst, implantation, and live birth, but not for euploidy., What Is Known Already: The gold standard for embryo selection is still morphological evaluation conducted by embryologists. Since the introduction of time-lapse technology to embryo culture, many algorithms for embryo selection have been developed based on embryo morphokinetics, providing complementary information to morphological evaluation. However, manual annotations of developmental events and application of algorithms can be time-consuming and subjective processes. The introduction of automation to morphokinetic annotations is a promising approach that can potentially reduce subjectivity in the embryo selection process and improve the workflow in IVF laboratories., Study Design, Size, Duration: This observational, retrospective cohort study was performed in a single IVF clinic between 2018 and 2021 and included 3736 embryos from oocyte donation cycles (423 cycles) and 1291 embryos from autologous cycles with preimplantation genetic testing for aneuploidies (PGT-A, 185 cycles). Embryos were classified on Day 3 with a score from 1 (best) to 5 (worst) by the automatic embryo assessment algorithm. The performance of the embryo classification model for blastocyst development, implantation, live birth, and euploidy prediction was assessed., Participants/materials, Setting, Methods: All embryos were monitored by a time-lapse system with an automatic cell-tracking and embryo assessment software during culture. The embryo assessment algorithm was applied on Day 3, resulting in embryo classification from 1 to 5 (from highest to lowest developmental potential) depending on four parameters: P2 (t3-t2), P3 (t4-t3), oocyte age, and number of cells. There were 959 embryos selected for transfer on Day 5 or 6 based on conventional morphological evaluation. The blastocyst development, implantation, live birth, and euploidy rates (for embryos subjected to PGT-A) were compared between the different scores. The correlation of the algorithm scoring with the occurrence of those outcomes was quantified by generalized estimating equations (GEEs). Finally, the performance of the GEE model using the embryo assessment algorithm as the predictor was compared to that using conventional morphological evaluation, as well as to a model using a combination of both classification systems., Main Results and the Role of Chance: The blastocyst rate was higher with lower the scores generated by the embryo assessment algorithm. A GEE model confirmed the positive association between lower embryo score and higher odds of blastulation (odds ratio (OR) (1 vs 5 score) = 15.849; P < 0.001). This association was consistent in both oocyte donation and autologous embryos subjected to PGT-A. The automatic embryo classification results were also statistically associated with implantation and live birth. The OR of Score 1 vs 5 was 2.920 (95% CI 1.440-5.925; P = 0.003; E = 2.81) for implantation and 3.317 (95% CI 1.615-6.814; P = 0.001; E = 3.04) for live birth. However, this association was not found in embryos subjected to PGT-A. The highest performance was achieved when combining the automatic embryo scoring and traditional morphological classification (AUC for implantation potential = 0.629; AUC for live-birth potential = 0.636). Again, no association was found between the embryo classification and euploidy status in embryos subjected to PGT-A (OR (1 vs 5) = 0.755 (95% CI 0.255-0.981); P = 0.489; E = 1.57)., Limitations, Reasons for Caution: The retrospective nature of this study may be a reason for caution, although the large sample size reinforced the ability of the model for embryo selection., Wider Implications of the Findings: Time-lapse technology with automated embryo assessment can be used together with conventional morphological evaluation to increase the accuracy of embryo selection process and improve the success rates of assisted reproduction cycles. To our knowledge, this is the largest embryo dataset analysed with this embryo assessment algorithm., Study Funding/competing Interest(s): This research was supported by Agencia Valenciana de Innovació and European Social Fund (ACIF/2019/264 and CIBEFP/2021/13). In the last 5 years, M.M. received speaker fees from Vitrolife, Merck, Ferring, Gideon Richter, Angelini, and Theramex, and B.A.-R. received speaker fees from Merck. The remaining authors have no competing interests to declare., Trial Registration Number: N/A., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Research Question: Is embryo selection by Dana (automatic software for embryo evaluation) associated with a higher implantation rate in IVF treatments?, Design: A three-phase study for Dana system's validation: creation of a data-cloud of known implantation data (KID) embryos from 1676 transferred embryos; embryo evaluation by Dana considering manual annotations and embryo development videos (389 transferred embryos); and validation of Dana automatic selection, without embryologist's intervention (147 transferred embryos); RESULTS: The implantation rate of the 1021 KID embryos from phase 1 served to set four grades of embryos referring to implantation rate: A = 34%, B = 25%, C = 24%, and D = 19%. Phase 2: a classification ranking according to the unit average distance (UAD) and implantation potential was established: top (UAD ≤0.50), high (UAD = 0.51-0.66), medium (UAD = 0.67-1.03) and low (UAD >1.03). Pregnancy rates were 59%, 46%, 36% and 28%, respectively (P < 0.001). Phase 3: embryos were automatically categorized according to Dana's classification ranking. Most implanted embryos were found in groups top, high and medium (UAD ≤1.03), whereas the implantation rate in group low (UAD >1.03) was significantly lower: 46% versus 25%, respectively (P = 0.037). The twin gestation rate was higher when number of top embryos (UAD ≤0.5) transferred were two (52%) versus one (25%) (P < 0.001)., Conclusions: Embryo selection based on Dana ranking increases the success of IVF treatments at least in oocyte donation programmes. The multicentre nature of the study supports its applicability at different clinics, standardizing the embryo development's interpretation. Dana's innovation is that the system increases its accuracy as the database grows., (Copyright © 2020 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

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., (Copyright © 2020 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Purpose: To demonstrate whether the standard morphokinetic markers used for embryo selection have a similar relationship to blastocyst formation and implantation in two large clinical data sets., Methods: This is a retrospective cohort analysis striving to answer two distinct questions utilizing data sets from two large IVF clinics. Blastocysts (BL) and implanted blastocysts (I) in both clinics, IVI-Valencia (BL = 11,414, I = 479) and WMC (BL = 15,902; I = 337), were cultured in a time-lapse system (EmbryoScope, Vitrolife, Sweden). The study was designed to assess the relationship between early morphokinetic hallmarks and BL development, with a secondary analysis of implantation rates following single-embryo day 3 and day 5 transfers., Results: We performed a detailed graphical analysis for t3, t5, duration of the second cell cycle (cc2) (t3-t2), and the ratio (t5-t3)/(t5-t2). The t5 timing was not affected between the clinics. However, Weill Cornell Medicine's (WCM) proportions were significantly affected by having BL vs. not. A significant decrease of blastocysts with longer t5 in WCM data, while t5 was more informative in the IVI data set for the implantation rate., Conclusions: Morphokinetic intervals for early cleavages were distributed differently between the clinics. Incorporation of embryo-selection algorithms depends on the individual clinic's selected developmental hallmarks, all of which must be validated before incorporation into clinical practice.

In recent years the increased efforts intended for improving future outcomes in the laboratory have focused mostly on the search of additional markers of embryo quality to add up present embryo selection criteria. Time-lapse system involves an alternative tool in assisted reproduction techniques, being able to improve the embryo selection from a dynamic and interactive approach while standard embryo assessment implies a subjective and static morphology evaluation and consequently reducing the information gained for embryo selection, time-lapse technology adds several morphokinetic parameters, providing additional input for embryo evaluation. This further information represents a challenge for a potential improvement in implantation rates and reproductive outcomes. This article focuses on the different time-lapse systems burgeoning on the market and the use of morphokinetics as a predictor of embryo implantation.

Time-lapse microscopy (TLM) is an exciting novel technology with great potential for enhancing embryo selection in the embryology laboratory. This non-invasive objective assessment of embryos has provided a new tool for predicting embryo development and implantation potential. TLM detects several morphological phenomena that are often missed with static observations using conventional incubators, such as irregular divisions, blastocyst collapse and re-expansion, timing of blastocoel appearance, and timing of formation and internalization of fragments. Nevertheless, it should be recognized that conventional morphological assessment has been widely accepted as the gold standard by most embryologists. TLM can enhance conventional morphological assessments to improve embryo selection and subsequent reproductive outcomes. Furthermore, morphokinetic parameters can aid in differentiating between euploid and aneuploid embryos, although they are not sufficiently accurate to replace preimplantation genetic testing for aneuploidy. Morphokinetic assessment together with chromosomal screening may ultimately help identify euploid embryos with the highest developmental potential., (Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To describe the morphological dynamics of vitrified/warmed blastocysts and to identify quantitative morphological variables related to implantation. Subsequently, by using the most predictive parameters, to develop a hierarchical model by subdividing vitrified/warmed blastocysts into categories with different implantation potentials., Design: Observational, retrospective, cohort study., Setting: University-affiliated private IVF center., Patient(s): The study included 429 vitrified/warmed blastocysts with known implantation data, which were evaluated by time-lapse imaging. Blastocysts were routinely placed in EmbryoScope (Vitrolife) immediately after warming until transfer., Intervention(s): None., Main Outcome Measure(s): Embryos were vitrified and warmed by the Cryotop method (KitazatoBiopharma). The studied variables included the initial and minimum thicknesses of zona pellucida (μm), the initial and maximum areas (μm 2 ), the area of inner cell mass (μm 2 ), expansion (whether the embryo reexpands or not after warming), and collapsing or contraction after warming. After defining the optimal ranges according to the consecutive quartiles with the highest probability of implantation, a logistic regression analysis was performed by combining the former variables and the blastocyst morphological classification criteria defined by the Spanish Association of Embryologists into A, B, C, or D categories., Result(s): Reexpansion of vitrified/warmed blastocysts correlated strongly with implantation (44.6% for reexpanded vs. 6.5% for the blastocysts that did not reexpand after warming). Throughout the logistic regression analysis, the model identified the maximum blastocyst area, odds ratio (OR) = 0.41 (95% confidence interval [CI], 0.22-0.77), followed by the initial area, OR = 0.62 (95% CI, 0.35-1.08) as the most predictive variables related to implanting embryos. Blastocyst morphology was not considered relevant in our model. The hierarchical tree model subdivided embryos into four categories, A-D, with lowering expected implantation potentials (from 47.3% for A to 14.2% for D)., Conclusion(s): The analysis of warmed blastocysts by time-lapse imaging may provide objective quantitative markers for the blastocyst implantation potential. We propose a hierarchical model to classify vitrified/warmed blastocysts according to their implantation probability. The observed correlations and the proposed algorithm should be validated in a prospective trial to evaluate its efficacy., (Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To analyze whether oocyte vitrification may affect subsequent embryo development from a morphokinetic standpoint by means of time-lapse imaging., Design: Observational cohort study., Setting: University-affiliated private IVF center., Patient(s): Ovum donation cycles conducted with the use of vitrified (n = 631 cycles; n = 3,794 embryos) or fresh oocytes (n = 1,359 cycles; n = 9,935 embryos) over 2 years., Interventions(s): None., Main Outcome Measure(s): Embryo development was analyzed in a time-lapse imaging incubator. The studied variables included time to 2 cells (t2), 3 cells (t3), 4 cells (t4), 5 cells (t5), morula (tM), and cavitated, early, and hatching blastocyst (tB, tEB, tHB) as well as 2nd cell cycle duration (cc2 = t3 - t2). All of the embryos were classified according to the hierarchic tree model currently used for embryo selection. The analyzed variables were compared with the use of analysis of variance or chi-square and included 95% confidence intervals (CIs)., Result(s): The embryos that originated from vitrified oocytes showed a delay of ∼1 hour from the first division to 2 cells (t2) to the time of blastulation (tB). The embryos that originated from vitrified oocytes showed a delay of ∼1 hour from the 1st division to 2 cells (t2) to the time of blastulation (tB) (P<.05). The proportions of embryos allocated to categories A-E in the hierarchical tree were similar between groups. No differences in implantation rates between the fresh (51.3% [95% CI 47.1%-55.7%]) and vitrified (46.4% [95% CI 38.4%-54.4%]) groups were found., Conclusion(s): The embryo quality of vitrified oocytes was not impaired: cc2, quality according to our hierarchic morphokinetic model, and implantation rates were similar between fresh and vitrified oocytes. However, morphokinetic differences were observed from t2 to tB. Our main study limitation was the retrospective nature of the analysis, although a large database was studied., (Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To study nucleation status in two- and four-cell embryos and its effect on reproductive outcomes., Design: Retrospective cohort study., Setting: University-affiliated private center., Patient(s): A total of 1,679 embryos from 940 oocyte donation cycles from May 2012 to May 2014., Intervention(s): None., Main Outcome Measure(s): Implantation, morphokinetics, and nucleation status restoration., Result(s): Multinucleation was present in 42.53% of embryos with known implantation data at the two-cell stage; it was present in approximately 14% of them at the four-cell stage. In all, 73.4% of the embryos were multinucleated at two cells and restored their nucleation status when they cleaved into four cells. Embryos with blastomeres multinucleated (more than two nuclei) at the four-cell stage showed a lower implantation rate. The average length of S-phase in the first embryo cell cycle in the positive known implantation data (KID+) embryos was longer than in KID- (15.50 hours vs. 14.38 hours) and slightly shorter in the second embryo cell cycle (8.35 hours in KID+ vs. 8.60 hours in KID-)., Conclusion(s): Multinucleation in two-cell-stage embryos is a frequent event, which is reversible in a high proportion of embryos, without impact on the implantation rate; and embryos with multinucleated blastomeres have a reduced outcome compared with those with binucleated blastomeres when multinucleation is present in four-cell-stage embryos., (Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Study Question: Is there an association between blastocyst collapse patterns and implantation potential?, Summary Answer: Embryos that exhibit collapse are as likely to hatch as those that do not, but are less likely to implant and should not be replaced if alternatives are available., What Is Known Already: Studies of blastocyst collapse in different species of mammals have found that most blastocysts, that experience consecutive weak contractions, hatch successfully whereas those that exhibit strong contractions or collapse, fail to hatch., Study Design, Size, Duration: Retrospective cohort study. Seven hundred and fifteen transferred blastocysts were analyzed from July 2012 to May 2013., Participants/materials, Setting, Methods: University-affiliated infertility center. Participant patients were recipients of oocyte donation and autologous IVF cycles (n = 460). Embryo development was analyzed with a time-lapse imaging system. Variables studied included blastocyst collapse (defined as the separation of ≥50% of the surface of the trophectoderm of the blastocyst from the zona pellucida), kinetic variables, embryo morphology, implantation and clinical pregnancy rates., Main Results and the Role of Chance: A total of 139 blastocysts presented collapse (19.4%), of these 8 presented 2 collapses and 2 presented 3 collapses. The timings of embryo cleavages and the time taken to reach the morula stage and blastulation were significantly shorter in embryos with collapse than in those without. Implantation rates were compared in cycles where either all or none of the embryos replaced, implanted so that implantation data were known for every embryo. Among 408 embryos without collapse and 94 embryos with at least one collapse (94) the implantation rates were 48.5% (95% confidence intervals (CI) 46.7-53.4%) and 35% (95% CI 25.3-44.9%), respectively. The percentage of embryos that hatched was similar in both groups 28.7 and 31%, respectively., Limitations, Reasons for Caution: The retrospective nature of the study limits its potential value., Wider Implications of the Findings: Study the collapse pattern of the blastocyst, may assist selection of the blastocysts most likely to implant and increase IVF/ICSI success rates., (© The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

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., (Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

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

Objective: To analyze the reproductive outcome of recipients of donated ova according to their body mass index (BMI)., Design: Twelve-year retrospective cohort analysis., Setting: Fertility clinics., Patient(s): 9,587 first cycles of ovum donation with ova from normoweight donors., Intervention(s): Recipients divided according to their BMI to analyze IVF laboratory and outcome parameters: lean with BMI <20 kg/m(2) (n = 1,458; 15.2%); normoweight with BMI 20-24.9 kg/m(2) (n = 5,706; 59.5%), overweight with BMI 25-29.9 kg/m(2) (n = 1,770; 18.5%), and obese with BMI ≥30 kg/m(2) (n = 653; 6.8%)., Main Outcome Measure(s): Implantation, biochemical and clinical pregnancy, miscarriage, and live-birth rates., Result(s): In vitro fertilization laboratory parameters did not differ according to BMI. However, implantation, pregnancy, clinical pregnancy, twin pregnancy, and live-birth rates were significantly reduced as BMI increased. In the lean, normoweight, overweight, and obese groups, the implantation rate was 40.4%, 39.9%, 38.5%, and 30.9%, clinical pregnancy rate was 56.9%, 55.9%, 54.3%, and 45.3%, and live-birth rate was 38.6%, 37.9%, 34.9%, and 27.7%, respectively. However, clinical miscarriage rates were similar in all the groups., Conclusion(s): Female obesity impairs the reproductive outcome of ovum donation probably as a result of reduced uterine receptivity., (Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Prostaglandin (PG) signaling has been implicated in embryonic implantation in several animal species including humans; however, this knowledge has not yet been clinically translated. The objective of this work is to investigate whether PGE2 and PGF2α in endometrial fluid (EF) can be used as biomarkers of human embryonic implantation., Patients and Methods: Lipidomic profile of human EF (n = 173) obtained through natural cycles, hormonal replacement therapy, controlled ovarian stimulation, and refractory endometrium induced by the insertion of an intrauterine device was analyzed by liquid chromatography and tandem mass spectrometry. Immunohistochemistry, Western blotting, immunolocalization of PG receptors on mouse embryos, embryo adhesion assay, pharmacological interventions, and statistical analysis were conducted., Results: PGE2 and PGF2α concentrations increased significantly in the human EF during the window of implantation in natural cycles and assisted reproductive technologies patients undergoing in vitro fertilization and ovum donation. This profile was abrogated in the refractory endometrium. We also demonstrated that PGE2 and PGF2α synthases are located in the endometrial epithelium being hormonally regulated during the window of implantation, and PG receptors are expressed in the trophoectoderm and inner cell mass of mouse blastocysts. Using an in vitro model of embryo adhesion, we demonstrated that inhibition of PGE2 and PGF2α or PG receptors (EP2 and FP) prevents embryo adhesion, which can be overcome by adding these molecules back or using their agonists. Finally, in a pilot study, we demonstrated that PGE2 and PGF2α levels from EF 24 hours prior to embryo transfer could predict pregnancy outcome., Conclusions: Our results suggest that PGE2 and PGF2α concentrations 24 hours prior to embryo transfer are potential noninvasive biomarkers of endometrial receptivity.

Incorporation of time-lapse imaging in the field of IVF has provided much information about embryo development. The combination of the embryo appearance (morphology) and the importance of when and how the cellular processes that lead to this appearance occur (kinetics) are now integrated into the unique concept of morphokinetics. At present, efforts are focused on using this information to improve embryo selection and existing success rates without losing sight of the ever-present objective of implementing a single ET strategy to avoid multiple gestations. Several investigative groups have identified predictive morphokinetic variables for embryo viability and implantation potential. Promising supplementary models of embryo selection based on time-dependent markers have been proposed and are currently being verified in prospective trials. Pending further results of these studies that confirm the clinical validity of time-lapse imaging, the present article tries to summarize the studies conducted to date to take stock of what has been done and the prospects that are emerging from this technology., (Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate embryos with direct cleavage (≤5 hours) from two to three cells (DC2-3) and correlate this morphokinetic parameter to implantation and ongoing pregnancy., Design: Clinical multicenter retrospective study., Setting: Private in vitro fertilization (IVF) centers., Patient(s): From three clinics, a total of 979 treatments including 5,225 embryos using autologous or donated oocytes, of which 1,659 embryos were transferred., Intervention(s): None., Main Outcome Measure(s): Clinical pregnancy confirmed by ultrasound in week 7., Result(s): Of the total embryo cohort, 715 (13.7%) underwent direct cleavage from two to three cells, 1,659 embryos were transferred to recipients, and 109 of the transferred embryos cleaved directly from two to three cells (6.6%). Only one DC2-3 embryo was known to result in a clinical pregnancy (1%) and 80 (73.4%) DC2-3 embryos did not implant. Of the 1,550 embryos transferred not showing DC2-3, 203 embryos were from treatments with 100% implantation (13.1%), and 804 (51.8%) embryos did not implant. The known implantation rate of DC2-3 embryos was statistically significantly lower than for embryos with a normal cleavage pattern (1.2% vs. 20.2%, respectively)., Conclusion(s): Embryos with DC2-3 had a statistically significantly lower implantation rate than embryos with a normal cleavage pattern, suggesting that rejection of these embryos for transfer could improve the implantation rate., (Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate the effect of adenomyosis on endometrial gene expression and its correlation with clinical outcome., Design: Transcriptomic analysis of the endometrium of women with adenomyosis during the window of implantation. Retrospective matched cohort study of the impact of adenomyosis on oocyte donation (OD) outcome., Setting: University-affiliated infertility clinic (2005-2009)., Patient(s): Endometrial samples were analyzed using microarrays in women with adenomyosis and healthy controls. The clinical study included three groups: adenomyosis, endometriosis, and control., Intervention(s): Endometrial biopsies in natural cycles 7 days after the LH peak; controlled ovarian stimulation in donors; ET in recipients after replacement therapy., Main Outcome Measure(s): Differentially expressed genes; implantation, pregnancy, miscarriage, and term pregnancy rates in OD., Result(s): There is a similar endometrial gene expression pattern in both the adenomyosis group and controls, and nonparametric tests revealed 34 dysregulated genes in adenomyosis patients but none belonged to the group of window of implantation genes. Implantation in OD did not differ among the three groups. However, miscarriage was significantly higher in the adenomyosis group vs. the adenomyosis + endometriosis and control groups. Term pregnancy rate was also significantly lower in the adenomyosis group compared with others., Conclusion(s): Clinical and molecular data show that implantation is not affected by adenomyosis, but the higher miscarriage rates associated with this condition lead to lower term pregnancy rates, indicating a clear negative effect on the final outcome of OD., (Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Time-lapse observation presents an opportunity for optimizing embryo selection based on morphological grading as well as providing novel kinetic parameters, which may further improve accurate selection of viable embryos. The objective of this retrospective study was to identify the morphokinetic parameters specific to embryos that were capable of implanting. In order to compare a large number of embryos, with minimal variation in culture conditions, we have used an automatic embryo monitoring system., Methods: Using a tri-gas IVF incubator with a built-in camera designed to automatically acquire images at defined time points, we have simultaneously monitored up to 72 individual embryos without removing the embryos from the controlled environment. Images were acquired every 15 min in five different focal planes for at least 64 h for each embryo. We have monitored the development of transferred embryos from 285 couples undergoing their first ICSI cycle. The total number of transferred embryos was 522, of which 247 either failed to implant or fully implanted, with full implantation meaning that all transferred embryos in a treatment implanted., Results: A detailed retrospective analysis of cleavage times, blastomere size and multinucleation was made for the 247 transferred embryos with either failed or full implantation. We found that several parameters were significantly correlated with subsequent implantation (e.g. time of first and subsequent cleavages as well as the time between cleavages). The most predictive parameters were: (i) time of division to 5 cells, t5 (48.8-56.6 h after ICSI); (ii) time between division to 3 cells and subsequent division to 4 cells, s2 (≤ 0.76 h) and (iii) duration of cell cycle two, i.e. time between division to 2 cells and division to 3 cells, cc2 (≤ 11.9 h). We also observed aberrant behavior such as multinucleation at the 4 cell stage, uneven blastomere size at the 2 cell stage and abrupt cell division to three or more cells, which appeared to largely preclude implantation., Conclusions: The image acquisition and time-lapse analysis system makes it possible to determine exact timing of embryo cleavages in a clinical setting. We propose a multivariable model based on our findings to classify embryos according to their probability of implantation. The efficacy of this classification will be evaluated in a prospective randomized study that ultimately will determine if implantation rates can be improved by time-lapse analysis.

Objective: To evaluate the effect of different ovarian stimulation protocols on oocyte respiration and to investigate the relationship between oocyte oxygen consumption and reproductive outcome., Design: Prospective observational cohort study., Setting: Infertility clinic in a university hospital., Patient(s): A total of 349 oocytes from 56 IVF treatment cycles in our oocyte donation program., Intervention(s): None., Main Outcome Measure(s): Average oocyte oxygen consumption rate in fmol/s. We correlated oxygen consumption values with ovarian stimulation features, fertilization, embryo quality on days 2 and 3, and implantation., Result(s): Differences in the measured oxygen consumption rates were found depending on which type of gonadotropins were used in the stimulation protocol. Higher consumption rates were found for oocytes that underwent normal fertilization compared with rates from nonfertilized or abnormal oocytes (odds ratio = 1.340; 95% confidence intervals = 1.037-1.732). Furthermore, higher oxygen consumption was observed for those oocytes which generated embryos that implanted compared with those that did not implant (6.21 ± 0.849 fmol/s vs. 5.23 ± 0.345 fmol/s., Conclusion(s): Measurement of oxygen consumption rates for individual oocytes before fertilization provides a noninvasive marker of oocyte quality and hence a quantitative assessment of the reproductive potential for the oocyte., (Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Context: Uterine leiomyomas are the most frequent benign tumors during reproductive age. Whether intramural leiomyomas cause infertility and should be removed is controversial because no study has addressed the underlying mechanism of infertility., Objective: The objective of the study was to test the effect of intramural leiomyomas on endometrial function by comparing gene during the window of implantation and implantation in an oocyte donation program, in which the quality of the embryos replaced is similar and the endocrine environment of the endometrium is standardized by exogenous steroids., Design: Human endometria of women with single intramural leiomyomas (group A, <5 cm and group B, > or =5 cm) and controls (group C) were collected on day LH+7 and processed for histology and gene expression analysis, using different methods and validated by quantitative RT-PCR. To compare in vitro fertilization outcome, a total of 1035 cases from our oocyte donation database were included, comprising patients with one fibroid less than 5 cm (A1, n = 532); two leiomyomas less than 5 cm (A2, n = 128); three or more leiomyomas less than 5 cm (A3, n = 125); one fibroid 5 cm or greater (B, n = 22); and two control groups: C1 (n = 93), women with previous myomectomy; and C2 (n = 135), women without uterine pathology treated on the same dates as C1., Results: There was a strong positive and negative correlation in the expression profile of 69 genes according to the leiomyomas's size, but only three of the 25 genes related to the window of implantation were dysregulated. Term pregnancy rates after oocyte donation were 36.9, 34.1, 39.0, 36.4, 39.2, and 42.6% (P = 0.769) among the established groups. Similarly, no correlation between implantation and miscarriage with leiomyoma number and size was found., Conclusions: This study provides evidence that intramural leiomyomas not affecting the endometrial cavity alters the expression pattern of some endometrial genes, but the genes involved in implantation are not affected. This is confirmed by leiomyomas having no effect on oocyte donation outcome when the size and number of leiomyomas are analyzed.

Objective: To compare outcome parameters and cumulative pregnancy rates (PRs) in oocyte donation cycles over a period of 10 years., Design: Retrospective study., Setting: University-affiliated assisted reproductive technology program., Patient(s): Women undergoing oocyte donation (10,537 cycles) between 1995 and 2005., Intervention(s): Ovarian stimulation and oocyte retrieval in donors. Embryo transfer performed in recipients after endometrial preparation., Main Outcome Measure(s): Outcome parameters and cumulative PRs were calculated and compared in relation to indication, age, and origin of sperm used., Result(s): Overall PR, implantation rate, clinical PR, and miscarriage rate per embryo transfer performed were 54.9%, 27%, 50.3%, and 19%, respectively. Ongoing PR per transfer was 40.2%, and twin and high-order multiple PRs were 39% and 6%, respectively. Mean number of embryos transferred was reduced from 3.6 +/- 0.8 to 1.9 +/- 0.3, implantation rate improved from 16.7% to 38.3%, and ongoing PR improved from 31% to 44.3%. Cumulative PRs did not differ significantly among different indications for oocyte donation, age groups, or origin of sperm used for oocyte insemination. Overall cumulative PRs after three and five cycles were calculated as 87% and 96.8%, respectively., Conclusion(s): Significant improvements in outcome parameters were achieved within 10 years. Similar cumulative PRs were observed regardless of recipient age, indication for oocyte donation, or sperm origin.

Chemokines are a family of small polypeptides which specialize in the attraction of leukocytes. The presence of specific leukocyte subsets at the implantation site is an important element of the complex, and not completely understood, process of embryonic implantation. This report includes the investigation of the in-vivo immunolocalization and hormonal regulation of interleukin (IL)-8, monocyte chemotactic protein (MCP)-1 and RANTES (regulated upon activation normal T-cell expressed and secreted) in the human endometrium during hormone replacement therapy cycles for oocyte recipients in an IVF programme. In addition, we have analysed the embryonic regulation of these endometrial epithelial chemokines (IL-8 and MCP-1) using an in-vitro model for the apposition phase of human implantation by co-culturing single human embryos until the blastocyst stage with human endometrial epithelial cells (EEC). IL-8 and MCP-1 were immunolocalized in the human endometrium to the glandular and lumenal epithelium as well as to the endothelial cells. RANTES was mainly localized to the stromal compartment and endothelial cells. The immunoreactive levels of endometrial IL-8 and MCP-1 were up-regulated by the administration of progesterone during the receptive phase of the cycle. Furthermore, it was demonstrated that, in vitro, the human blastocyst does not produce measurable amounts of IL-8, MCP-1 or RANTES; however, it does up-regulate EEC IL-8 mRNA expression (P < 0.05) and protein production (P < 0.05), but not IL-8 secretion. The human embryo did not regulate EEC MCP-1 expression. These results provide evidence of hormonal and embryonic regulation of specific endometrial chemokines, suggesting two different but related mechanisms to induce the production of chemokines by the EEC, thus contributing to the attraction of specific leukocyte populations during the peri-implantation phase.

As it approaches the maternal surface, the attaching embryo encounters the epithelial glycocalyx, which contains the mucin, MUC1. A high density of MUC1 at the cell surface can inhibit cell adhesion. This raises the possibility of the existence of a uterine barrier to implantation that might allow maternal rejection of poorer quality embryos. To investigate the mechanism of implantation, human embryos were incubated with endometrial epithelial monolayers. Hatched blastocysts were found to attach readily to the epithelial surface. MUC1 was lost from epithelial cells beneath and near to the attached embryo, while normal expression persisted in neighbouring cells.

Embryonic implantation requires co-ordinated development of the blastocyst and the maternal endometrium. Considerable advances have been made in understanding the cell biology of these partner tissues separately. Nevertheless, communication between these tissues and the reciprocal effects of these tissues on each other constitutes an exciting and as yet unsolved paradigm in reproductive medicine. Crosstalk between the embryo, endometrium and the corpus luteum is known to occur in ruminants and primates, and, more specifically, endometrial-embryonic interactions are reported in rodents and primates. In this review, an in vitro model for analysing the interactions between human endometrial epithelium and blastocyst in the adhesion phase of embryonic implantation is presented. The results of investigations of embryonic regulation of endometrial epithelial molecules such as adhesion molecules, mucins, chemokines and cytoskeleton proteins are also presented.

STUDY QUESTION Could an artificial intelligence (AI) algorithm predict fetal heartbeat from images of vitrified-warmed embryos? SUMMARY ANSWER Applying AI to vitrified-warmed blastocysts may help predict which ones will result in implantation failure early enough to thaw another. WHAT IS KNOWN ALREADY The application of AI in the field of embryology has already proven effective in assessing the quality of fresh embryos. Therefore, it could also be useful to predict the outcome of frozen embryo transfers, some of which do not recover their pre-vitrification volume, collapse, or degenerate after warming without prior evidence. STUDY DESIGN, SIZE, DURATION This retrospective cohort study included 1109 embryos from 792 patients. Of these, 568 were vitrified blastocysts cultured in time-lapse systems in the period between warming and transfer, from February 2022 to July 2023. The other 541 were fresh-transferred blastocysts serving as controls. PARTICIPANTS/MATERIALS, SETTING, METHODS Four types of time-lapse images were collected: last frame of development of 541 fresh-transferred blastocysts (FTi), last frame of 467 blastocysts to be vitrified (PVi), first frame post-warming of 568 vitrified embryos (PW1i), and last frame post-warming of 568 vitrified embryos (PW2i). After providing the images to the AI algorithm, the returned scores were compared with the conventional morphology and fetal heartbeat outcomes of the transferred embryos (n = 1098). The contribution of the AI score to fetal heartbeat was analyzed by multivariate logistic regression in different patient populations, and the predictive ability of the models was measured by calculating the area under the receiver-operating characteristic curve (ROC-AUC). MAIN RESULTS AND THE ROLE OF CHANCE Fetal heartbeat rate was related to AI score from FTi (P  < 0.001), PW1i (P  < 0.05), and PW2i (P  < 0.001) images. The contribution of AI score to fetal heartbeat was significant in the oocyte donation program for PW2i (odds ratio (OR)=1.13; 95% CI [1.04–1.23]; P  < 0.01), and in cycles with autologous oocytes for PW1i (OR = 1.18; 95% CI [1.01–1.38]; P  < 0.05) and PW2i (OR = 1.15; 95% CI [1.02–1.30]; P  < 0.05), but was not significantly associated with fetal heartbeat in genetically analyzed embryos. AI scores from the four groups of images varied according to morphological category (P  < 0.001). The PW2i score differed in collapsed, non-re-expanded, or non-viable embryos compared to normal/viable embryos (P  < 0.001). The predictability of the AI score was optimal at a post-warming incubation time of 3.3–4 h (AUC = 0.673). LIMITATIONS, REASONS FOR CAUTION The algorithm was designed to assess fresh embryos prior to vitrification, but not thawed ones, so this study should be considered an external trial. WIDER IMPLICATIONS OF THE FINDINGS The application of predictive software in the management of frozen embryo transfers may be a useful tool for embryologists, reducing the cancellation rates of cycles in which the blastocyst does not recover from vitrification. Specifically, the algorithm tested in this research could be used to evaluate thawed embryos both in clinics with time-lapse systems and in those with conventional incubators only, as just a single photo is required. STUDY FUNDING/COMPETING INTERESTS This study was supported by the Regional Ministry of Innovation, Universities, Science and Digital Society of the Valencian Community (CIACIF/2021/019) and by Instituto de Salud Carlos III (PI21/00283), and co-funded by European Union (ERDF, 'A way to make Europe'). M.M. received personal fees in the last 5 years as honoraria for lectures from Merck, Vitrolife, MSD, Ferring, AIVF, Theramex, Gedeon Richter, Genea Biomedx, and Life Whisperer. There are no other competing interests. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]