Evaluation of day one embryo quality and IVF outcome--a comparison of two scoring systems

Pronuclear score improves prediction of embryo implantation success in ICSI cycles

BACKGROUND

In assisted reproduction technology embryo competence is routinely evaluated on morphological criteria but efficacy remains relatively low. Additional information could be obtained by evaluating pronuclear (PN) morphology. Up to now controversial results have been reported about the prognostic value of PN score. One of the main limitations of literature data is the use of different PN classification methods. In this regard, in 2011 the ESHRE and Alpha Scientists in Reproductive Medicine defined three PN categories to standardize zygote assessment. In this study we evaluated whether the consensus ESHRE-Alpha system for the pronuclear scoring could be an useful additional criterion to improve prediction of embryo implantation potential.

METHODS

This is a retrospective, longitudinal, observational, cohort study. We included 3004 zygotes from 555 women who underwent ICSI treatment at our Center between January 2014 and June 2019. The PN were categorized as score 1: symmetrical, 2: non-symmetrical, 3: abnormal. A subset of 110 zygotes did not cleaved. On day 2-3 1163 embryos were transferred, 232 arrested, and 9 were cryopreserved. Among the 1490 embryos cultured up to day 5-7, 516 became blastocysts: 123 were transferred on day 5 and 393 were cryopreserved. Comparisons of age, cleavage and blastocyst rate, quality of embryos, implantation success among PN score groups were evaluated by chi-square test or Kruskal-Wallis test as appropriate. Potential predictors of embryo implantation were first tested in univariable analysis using generalized estimating equations taking into account correlation between embryos originated from the same patient. Then, variables potentially associated with implantation success (P<0.05) were included in a multivariable analysis for calculating the adjusted odds ratio (OR) and 95% confidence interval (CI).

RESULTS

There was no significant difference in patients'age, cleavage and blastulation rates, and embryo morphology among the three PNscore groups. The PN score 1-embryos had a greater implantation success respect to score 2-3-ones (OR 1.83; 95% CI 1.34-2.50, P=0.0001). Consistently, the pronuclear score remained predictive of implantation in top quality embryos (OR 1.68; 95%CI 1.17-2.42, P= 0.005).

CONCLUSIONS

The consensus pronuclear score may be routinely included among criteria for embryo evaluation to increase patients' chance of becoming pregnant.

Comparing the effect of sitagliptin and metformin on the oocyte and embryo quality in classic PCOS patients undergoing ICSI

BACKGROUND

Insulin resistance plays a major role in the pathogenesis of polycystic ovary syndrome (PCOS). Therefore, there is a growing interest in the use of insulin sensitizer drugs in the treatment of PCOS. Research in recent years has shown that sitagliptin has been reported to improve ovarian cycles and ovulation in PCOS patients.

AIMS

We aimed to compare the effects of metformin and sitagliptin on PCOS individuals undergoing ICSI.

METHODS

Sixty PCOS patients were divided into 3 groups: metformin, sitagliptin, and placebo group. Treatment was carried out 2 months before the start of the ovulation cycle and continued until the day of oocyte aspiration. The serum levels of total testosterone, estradiol, and fasting insulin along with the total number of retrieved, normal and abnormal MII, and fertilized oocytes, the number of transferred embryos (grades I, II and III), and biochemical and clinical pregnancy rates as well as the ovarian hyperstimulation syndrome (OHSS) were evaluated.

RESULTS

There was a significant reduction in the serum levels of Insulin and total testosterone in the treated groups compared with the placebo. The number of mature and normal MII oocytes increased significantly in the treated groups compared with the placebo. Moreover, the number of immature oocytes decreased significantly and the number of grade I embryos increases significantly in the sitagliptin group compared with the placebo group.

CONCLUSION

We conclude that sitagliptin can improve the maturation of oocytes and embryos' quality more effectively than metformin, in PCOS patients undergoing ICSI.

TRIAL REGISTRATION

Trial registration is NCT04268563 ( https://clinicaltrials.gov ).

The Vienna consensus: report of an expert meeting on the development of ART laboratory performance indicators

This proceedings report presents the outcomes from an international workshop supported by the European Society of Human Reproduction and Embryology (ESHRE) and Alpha Scientists in Reproductive Medicine, designed to establish consensus on definitions and recommended values for Indicators for the assisted reproductive technology (ART) laboratory. Minimum performance-level values ('competency') and aspirational ('benchmark') values were recommended for a total of 19 Indicators, including 12 Key Performance Indicators (KPIs), five Performance Indicators (PIs), and two Reference Indicators (RIs).

The Vienna consensus: report of an expert meeting on the development of art laboratory performance indicators

STUDY QUESTION

What are appropriate performance indicators (PIs) for ART laboratories for use in monitoring 'fresh' IVF and ICSI cycles?

SUMMARY ANSWER

Minimum performance (competence) levels and aspirational (benchmark) values were recommended for a total of 19 indicators, including 12 key PIs (KPIs), five PIs and two reference indicators (RIs).

WHAT IS ALREADY KNOWN

PIs are necessary for systematic monitoring of the laboratory and an important element within the Quality Management System. However, there are no established PIs for ART laboratories and there is very little evidence on the topic.

STUDY DESIGN SIZE DURATION

This is the report of a 2-day consensus meeting of expert professionals. As a starting point for the discussion, two surveys were organized to collect information on indicators used in IVF laboratories. During the meeting, the results of the surveys, scientific evidence (where available), and personal clinical experience where integrated into presentations by experts on specific topics. After presentation, each proposed indicator was discussed until consensus was reached within the panel.

PARTICIPANTS/MATERIALS SETTING METHODS

Expert professionals representing different countries and settings convened in the consensus meeting.

MAIN RESULTS AND THE ROLE OF CHANCE

The paper is divided in two parts: the workshop report and the recommendations of the expert panel. The second part reflects the discussion on each of the indicators, with the agreed definition, competence level and benchmark value for each of the 19 indicators, including 12 KPIs, 5 PIs and 2 RIs.

LIMITATIONS REASONS FOR CAUTION

The KPIs are mainly based on expert opinion. Future research may warrant an update of the recommended KPIs, their definition and the competence level and benchmark values.

WIDER IMPLICATIONS OF THE FINDINGS

Based on the information presented, each ART laboratory should select its own set of KPIs founded on laboratory organization, and processes.

STUDY FUNDING/COMPETING INTERESTS

The consensus meeting and writing of the paper was supported by funds from ESHRE and Alpha. Alpha gratefully acknowledges the following organizations for their financial support, through the provision of unrestricted educational grants: Global Fertility Alliance, Merck, Origio and Vitrolife. There are no conflicts of interest to disclose.

N-Acetylcysteine improves oocyte and embryo quality in polycystic ovary syndrome patients undergoing intracytoplasmic sperm injection: an alternative to metformin

Polycystic ovary syndrome (PCOS) is associated with low-quality oocytes. The aim of the present study was to investigate the effects of metformin (MET), N-acetylcysteine (NAC) and their combination on follicular fluid parameters, oocytes and embryo quality in PCOS patients. A prospective randomised placebo-controlled pilot study on 60 Iranian women with PCOS (aged 25–35 years) undergoing intracytoplasmic sperm injection (ICSI) was designed. Women were divided into four groups (n = 15 in each): (1) an MET, administered 1500 mg day–1 MET; (2) an NAC group, administered 1800 mg day–1 NAC; (3) an NAC + MET group; and (4) a placebo group. Drugs were administered from the 3rd day of previous cycle until the day of oocyte aspiration (6 weeks treatment in total). Data were analysed by one-way ANOVA, with significance set at P < 0.05. The number of immature and abnormal oocytes decreased significantly in the NAC compared with placebo group, with a concomitant increase in the number of good-quality embryos in the NAC group (P < 0.05). Malondialdehyde levels decreased significantly in the NAC and NAC + MET groups compared with the placebo-treated group (P < 0.02). In addition, there were significant decreases in leptin levels in the NAC, MET and NAC + MET groups compared with the placebo group (P < 0.001). Insulin and LH levels were significantly lower in the MET and NAC groups compared with the placebo-treated group (P < 0.02). We concluded that NAC improves oocyte and embryo quality and could be administered as an alternative to MET.

Timing of The First Zygotic Cleavage Affects Post-Vitrification Viability of Murine Embryos Produced In Vivo

Background

Timing of the first zygotic cleavage is an accurate predictor of embryo quality. Embryos that cleaved early (EC) have been shown to exhibit higher develop- mental viability compared to those that cleaved at a later period (LC). However, the vi- ability of EC embryos in comparison to LC embryos after vitrification is unknown. The present study aims to investigate the post-vitrification developmental viability of murine EC versus LC embryos.

Materials and Methods

In this experimental study, female ICR mice (6-8 weeks old) were superovulated and cohabited with fertile males for 24 hours. Afterwards, their ovi- ducts were excised and embryos harvested. Embryos at the 2-cell stage were catego- rized as EC embryos, while zygotes with two pronuclei were categorized as LC embryos. Embryos were cultured in M16 medium supplemented with 3% bovine serum albumin (BSA) in a humidified 5% CO₂atmosphere. Control embryos were cultured until the blastocyst stage without vitrification. Experimental embryos at the 2-cell stage were vitri- fied for one hour using 40% v/v ethylene glycol, 18% w/v Ficoll-70 and 0.5 M sucrose as the cryoprotectant. We recorded the numbers of surviving embryos from the control and experimental groups and their development until the blastocyst stage. Results were analyzed using the chi-square test.

Results

A significantly higher proportion of EC embryos (96.7%) from the control group developed to the blastocyst stage compared with LC embryos (57.5%, P<0.0001). Similarly, in the experimental group, a significantly higher percentage of vitrified EC embryos (69.4%) reached the blastocyst stage compared to vitrified LC embryos (27.1%, P<0.0001).

Conclusion

Vitrified EC embryos are more vitrification tolerant than LC embryos. Prese- lection of EC embryos may be used as a tool for selection of embryos that exhibit higher developmental competence after vitrification.

An overview of the available methods for morphological scoring of pre-implantation embryos in in vitro fertilization

Assessment of embryo quality in order to choose the embryos that most likely result in pregnancy is the critical goal in assisted reproductive technologies (ART). The current trend in human in vitro fertilization/embryo transfer (IVF/ET) protocols is to decrease the rate of multiple pregnancies after multiple embryo transfer with maintaining the pregnancy rate at admissible levels (according to laboratory standards). Assessment of morphological feathers as a reliable non-invasive method that provides valuable information in prediction of IVF/intra cytoplasmic sperm injection (ICSI) outcome has been frequently proposed in recent years. This article describes the current status of morphological embryo evaluation at different pre-implantation stages.

The strategy of group embryo culture based on pronuclear pattern on blastocyst development: a two center analysis

PURPOSE

To compare two embryo grouping strategies.

METHODS

Retrospective time-course analysis in two different centres. Two culture protocols were used at the zygote stage: "Random Group" in which zygotes were randomly grouped and "Definite Group" in which zygotes were grouped based on pronuclear pattern. Embryo culture was extended to blastocyst stage. Primary and secondary outcomes were respectively the blastulation rate and the cumulative clinical pregnancy and implantation rates.

RESULT(S)

A similar blastulation rate [42 and 41% day (5 + 6) blastocysts] was obtained in the two groups. Conversely, after adjusting for baseline and cycle variables, cumulative pregnancy [adjusted Odds Ratio = 2.10 (95%CI: 1.08-4.07)] and implantation [adjusted Odds Ratio = 1.78 (95%CI: 1.06-2.97)] rates were significantly higher in the "Random Group" compared to the "Definite Group".

CONCLUSION(S)

Two strategies of group culture gave similar results in terms of blastulation rate but the random grouping of zygotes improves pregnancy and implantation rates in IVF-cycles.

Morphological good-quality embryo has higher nucleus spreading rate/signal resolution rate in fluorescence in situ hybridization

PURPOSE

To evaluate the relationship between day 3 embryo quality and nucleus spreading rate/signal resolution rate in Fluorescence in situ hybridization (FISH) during the PGD procedure.

METHODS

This study was a retrospective data analysis. 367 day-3 embryos were classified based on morphological scoring: grade 1 to grade 4 were defined from worse to better embryo quality. Day 3 embryos were classified as good quality when the number of blastomeres was between 6 and 10 and grade better than 2'. Nucleus spreading rate, signal rate and the full signal rate were compared between embryos with different morphological scoring.

RESULTS

Nucleus spreading rate of blastomeres from morphological high-quality embryos was significantly higher (86.25 %) than from poor-quality embryos (76.53 %) (p < 0.05). The rate of blastomeres with full signals was significantly higher (79.32 %) in the morphological high-quality group than in poor-quality group (64.54 %) (p < 0.05). Similar results were found from day 3 embryos with cell number between 6 cells and 10 cells (nucleus spreading rate 86.01 vs. 76.34 %, p < 0.05; full signal rate 78.72 vs. 62.71 %, p < 0.05). Both have no significant difference in the signal rate (82.67 vs. 89.66 %; 83.10 vs. 89.95 %).

CONCLUSIONS

Blastomeres from day 3 embryos with better morphological quality had higher nucleus spreading rate and higher full signal rate during FISH. Through this study, we speculate on whether it should reconsider the necessity of FISH application in embryos with poor quality.

Pronuclear morphology evaluation for fresh in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles: a systematic review

The current systematic review was aimed to assess the effectiveness of the zygote morphology evaluation in fresh in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles. All available studies reporting on zygote morphology and clinical and/or biological outcomes were analyzed. Forty studies were included in the final analysis. Fourteen different zygote scoring systems were employed. Zygote morphology correlated significantly with embryo quality and cleavage, blastocyst stage, embryonic chromosome status, in a high proportion of the studies which assessed the specific outcome [15/25 (60%), 15/20 (75%), 7/8 (87.5%), 6/6 (100%), respectively]. On the other hand, only a reduced proportion of papers showed a statistically significant relationship between implantation, pregnancy and delivery/live-birth rates and zygote morphology score [12/23 (52.2%), 12/25 (48%), 1/4 (25%), respectively]. In conclusion, our findings demonstrate the lack of conclusive data on the clinical efficacy of the zygote morphology evaluation in fresh IVF/ICSI cycles, even if biological results showing a good relationship with embryo viability suggest a role in cycles in which the transfer/freezing is performed at day 1.

A Bayesian network model for predicting pregnancy after in vitro fertilization

We present a Bayesian network model for predicting the outcome of in vitro fertilization (IVF). The problem is characterized by a particular missingness process; we propose a simple but effective averaging approach which improves parameter estimates compared to the traditional MAP estimation. We present results with generated data and the analysis of a real data set. Moreover, we assess by means of a simulation study the effectiveness of the model in supporting the selection of the embryos to be transferred.

The combination of pronuclear and blastocyst morphology: a strong prognostic tool for implantation potential

PURPOSE

To (i) investigate a possible association between different features of pronuclear (PN) morphology and different features of blastocyst morphology, (ii) evaluate the combination of PN and blastocyst morphologies as a predictive factor for ICSI outcomes and (iii) identify possible contributing factors to poor PN morphology.

METHODS

This study included 908 normally fertilised zygotes reaching full blastocyst stage, obtained from 350 patients undergoing ICSI cycles, in which the implantations rates were 0 % or 100 %. The influence of PN morphology on blastocyst morphology and on the rates of pregnancy and miscarriage was investigated. Embryos were graded and split into three groups, taking into consideration both the PN and the blastocyst status. The pregnancy rate was compared among these groups.

RESULTS

Inner cell mass (ICM) alterations were correlated with the number of nucleolar precursor bodies (NPB), while trophectoderm alterations were correlated with the size of the pronuclei and the distribution of the NPB. The distribution of the NPB had an impact on the chances of pregnancy. A significant difference was observed among the groups regarding the pregnancy rate. The maternal age, number of aspirated follicles and number of retrieved oocytes influenced the incidence of PN defects.

CONCLUSIONS

These findings suggest that a lower oocyte yield may lead to higher-quality PN zygotes. In addition, different PN features may influence further embryo development, especially the quality of the blastocyst. Moreover, the association between PN and blastocyst morphology may be used as a prognostic tool for implantation.

Effect of sperm entry on blastocyst development after in vitro fertilization and intracytoplasmic sperm injection - mouse model

PURPOSE

To investigate whether in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), influence the embryo's development and its quality using the mouse as a model.

METHODS

Assisted fertilization was performed using ICSI and IVF. Fluorescent beads were adhered to the fertilization cone or place of previous sperm injection in the natural mated (NM), IVF and ICSI embryos, respectively. Embryo examination was carried out at the two-cell and blastocyst stage to determine the position of fluorescent bead. Protein expression was detected by fluorescence immunocytochemical staining and confocal microscopic imaging of blastocysts.

RESULTS

IVF and ICSI embryos developed at rates comparable to NM group. Embryos show similar expression patterns of two transcription factors, Oct4 and Cdx2. The most preferred place for spermatozoa attachment was the equatorial site of the egg, whether fertilization occurred in vitro or under natural conditions. We also link the sperm entry position (SEP) to embryo morphology and the number of cells at the blastocyst stage, with no influence of the method of fertilization.

CONCLUSIONS

IVF and ICSI, do not compromise in vitro pre-implantation development. Additional data, related to sperm entry, could offer further criteria to predict embryos that will implant successfully. Based on embryo morphology, developmental rate and protein expression level of key transcription factors, our results support the view that ART techniques, such as IVF and ICSI, do not perturb embryonic development or quality.

Time-Lapse Cleavage Rating Predicts Human Embryo Viability

Chronology of three consecutive mitotic events in human pre-implantation embryos was examined by time-lapse imaging. In zygotes producing well-formed and pregnancy-yielding expanded blastocysts, uniform time-patterning of cleavage clusters (c) and interphases (i) was revealed: i2=11±1, i3=15±1, i4=23±1 h / c2=15±5, c3=40±10, c4=55±15 min. Oppositely, shortened or prolonged durations of one or more cell cycles were strongly predictive of poor implantation and development. Furthermore, trichotomic mitosis was discovered in 17 % of cases - zygotes cleaved into 3 blastomeres and 2-cell embryos into 5-6 cells (instead of normal 2 and 4). During conventional clinical assessment, such embryos are indistinguishable from normal, often considered just-in-course of the next cell cycle. Only detailed time-lapse monitoring paced at 10-minute intervals had proven all these embryos to be absolutely unviable, even in rare cases when they reduced their hypercellularity to normal cell counts via cell-cell fusion. Overall, we demonstrate that time-lapse embryo cleavage rating (ECR) as a standalone diagnostic procedure allows for effective identification of viable early embryos with 90 % specificity, while elimination of good-looking but unviable embryos can be assumed with a specificity of 100 %. Thus, making this non-invasive and contactless approach worth of addition to routine embryo screening in clinical IVF programs.

The dynamics of endometrial growth and the triple layer appearance in three different controlled ovarian hyperstimulation protocols and their influence on IVF outcomes

The impact of endometrial growth to the triple layer, endometrial thickness, and echogenicity on IVF outcomes was investigated in the study. A retrospective analysis of 583 ICSI patients was conducted: 385 with a long GnRH agonist protocol, 114 with a short GnRH agonist, and 84 with a GnRH antagonist protocol. The progression of endometrial growth to the appearance of the triple layer, endometrial thickness, and echogenicity was compared between protocols. At least one high quality blastocyst was transferred in a double embryo transfer. The time of the appearance of the endometrial triple layer was statistically significant for the pregnancy rate only in the GnRH antagonist protocol. The endometrial thickness on the day of the appearance of the triple layer had a statistically significant influence on the pregnancy rate in the GnRH antagonist and in the long GnRH agonist protocols. The highest pregnancy rate for the long GnRH agonist and the GnRH antagonist protocols was observed when the endometrium thickness was 12-13 mm (61.6% and 58.8%, respectively). The endometrial echogenicity had a significant influence on the pregnancy rate only in the long GnRH agonist protocol. Endometrial features could be helpful parameters in IVF outcomes in particular controlled ovarian hyperstimulation protocols.