Randomized comparison of two different blastocyst grading systems

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality, or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariable logistic regression. We applied a Factorial Analysis of Mixed Data (FAMD) to reduce the potential collinearity between the covariates used in the model. All the blastocysts included in this study were obtained from the first ICSI freeze-all cycles. The cleavage and blastocysts stages were assessed between 67 ± 0.5 (day 3), 115 ± 0.5 (day 5), and 139 ± 0.5 (day 6) hours post-insemination (hpi), respectively. After adjusting for the day of transfer (day 5 or day 6) and FAMD dimensions, no statistical differences in a β-HCG, clinical pregnancy, and live birth were observed among the same-quality blastocysts derived from different day 3 embryo quality groups (top = A, good = B, and poor = C). Our findings showed that a day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles.

An annotated human blastocyst dataset to benchmark deep learning architectures for in vitro fertilization

Medical Assisted Reproduction proved its efficacy to treat the vast majority forms of infertility. One of the key procedures in this treatment is the selection and transfer of the embryo with the highest developmental potential. To assess this potential, clinical embryologists routinely work with static images (morphological assessment) or short video sequences (time-lapse annotation). Recently, Artificial Intelligence models were utilized to support the embryo selection procedure. Even though they have proven their great potential in different in vitro fertilization settings, there is still considerable room for improvement. To support the advancement of algorithms in this research field, we built a dataset consisting of static blastocyst images and additional annotations. As such, Gardner criteria annotations, depicting a morphological blastocyst rating scheme, and collected clinical parameters are provided. The presented dataset is intended to be used to train deep learning models on static morphological images to predict Gardner's criteria and clinical outcomes such as live birth. A benchmark of human expert's performance in annotating Gardner criteria is provided.

Investigating of the effects of trophectoderm morphology on obstetrics outcome in 5th day blastocyst transfer in patients with in vitro fertilization

Objective:

Trophectoderm (TE) cells are the first differentiating cells in embryo development and have epithelial features. TE cells, which associate with implantation of the blastocyst into the uterine endometrium, contribute to the formation of the placenta. Inner cells mass (ICM) together with TE cells are used for determining embryo quality. The aim of this study was to investigate the role of TE and ICM cells on pregnancy outcome in 5^th day blastocyst transferred in-vitro-fertilization (IVF) pregnancy.

Material and Methods:

This was a retrospective study using data from all patients who applied for blastocyst transfer IVF between January 2015 and March 2019 at the Reproductive Endocrinology and Infertility Center of Akdeniz University Faculty of Medicine, Department of Obstetrics and Gynecology. ALPHA İstanbul consensus evaluation system was used for grading of the blastocyst. The embryo quality, expansion, ICM and TE morphology of the 5^th day transferred blastocyst was assessed, together with abortion rate, live birth rate, pregnancy complications, and pregnancy outcomes.

Results:

There was a significantly increased risk of preeclampsia (PE) (7.8% vs 1.1%; p=0.041), preterm delivery (PD) (36% vs 17.7%; p=0.037), and antenatal bleeding rates (13.6% vs 5%; p=0.021) in TE-C compared to the TE-A + TE-B blastocysts. Furthermore, a higher rate of obstetric complications was observed in ICM-C compared to ICM-A and B (p=0.003). There was a significant correlation between TE morphology and implantation success, ongoing pregnancy rate, and abortion incidence.

Conclusion:

These results suggest that TE cell morphology is related to implantation success and pregnancy outcomes, especially in terms of the risk of abortion, PE, PD, and antenatal bleeding. It may be advisable to counsel women concerning possible poor obstetric outcome due to poor ICM quality. Future prospective and controlled studies are needed to clarify this association.

Time Series Prediction of Viable Embryo and Automatic Grading in IVF using Deep Learning

Background:

The process of In Vitro Fertilization (IVF) involves collecting multiple samples of mature eggs that are fertilized with sperms in the IVF laboratory. They are eventually graded, and the most viable embryo out of all the samples is selected for transfer in the mother’s womb for a healthy pregnancy. Currently, the process of grading and selecting the healthiest embryo is performed by visual morphology, and manual records are maintained by embryologists.

Objectives:

Maintaining manual records makes the process very tedious, time-consuming, and error-prone. The absence of a universal grading leads to high subjectivity and low success rate of pregnancy. To improve the chances of pregnancy, multiple embryos are transferred in the womb elevating the risk of multiple pregnancies. In this paper, we propose a deep learning-based method to perform the automatic grading of the embryos using time series prediction with Long Short Term Memory (LSTM) and Convolutional Neural Network (CNN).

Methods:

CNN extracts the features of the images of embryos, and a sequence of such features is fed to LSTM for time series prediction, which gives the final grade.

Results:

Our model gave an ideal accuracy of 100% on training and validation. A comparison of obtained results is made with those obtained from a GRU model as well as other pre-trained models.

Conclusion:

The automated process is robust and eliminates subjectivity. The days-long hard work can now be replaced with our model, which gives the grading within 8 seconds with a GPU.

Inter-centre reliability in embryo grading across several IVF clinics is limited: implications for embryo selection

RESEARCH QUESTION

What is the intra- and inter-centre reliability in embryo grading performed according to the Istanbul Consensus across several IVF clinics?

DESIGN

Forty Day 3 embryos and 40 blastocysts were photographed on three focal planes. Senior and junior embryologists from 65 clinics were invited to grade them according to the Istanbul Consensus (Study Phase I). All participants then attended interactive training where a panel of experts graded the same embryos (Study Phase II). Finally, a second set of pictures was sent to both embryologists and experts for a blinded evaluation (Study Phase III). Intra-centre reliability was reported for Study Phase I as Cohen's kappa between senior and junior embryologists; inter-centre reliability was instead calculated between senior/junior embryologists and experts in Study Phase I versus III to outline improvements after training (i.e. upgrade of Cohen's kappa category according to Landis and Koch).

RESULTS

Thirty-six embryologists from 18 centres participated (28% participation rate). The intra-centre reliability was (i) substantial (0.63) for blastomere symmetry (range -0.02 to 1.0), (ii) substantial (0.72) for fragmentation (range 0.29-1.0), (iii) substantial (0.66) for blastocyst expansion (range 0.19-1.0), (iv) moderate (0.59) for inner cell mass quality (range 0.07-0.92), (v) moderate (0.56) for trophectoderm quality (range 0.01-0.97). The inter-centre reliability showed an overall improvement from Study Phase I to III, from fair (0.21-0.4) to moderate (0.41-0.6) for all parameters under analysis, except for blastomere fragmentation among senior embryologists, which was already moderate before training.

CONCLUSIONS

Intra-centre reliability was generally moderate/substantial, while inter-centre reliability was just fair. The interactive training improved it to moderate, hence this workflow was deemed helpful. The establishment of external quality assessment services (e.g. UK NEQAS) and the avant-garde of artificial intelligence might further improve the reliability of this key practice for embryo selection.

Cellular Fragments in the Perivitelline Space Are Not a Predictor of Expanded Blastocyst Quality

The presence of cellular fragments in the perivitelline space is a commonly used parameter to determine quality before transfer of in vitro produced (IVP) embryos. However, this parameter is difficult to assess after blastocyst expansion. In this study, we used mechanical hatching to confirm the presence of cellular fragments in the perivitelline space of bovine IVP blastocysts. We further looked for associations between possible apoptosis within extruded cells/ cellular fragments and the quality of bovine blastocysts using quantitative RT-PCR and immunofluorescence. Surprisingly, more than 42% of expanded blastocysts had cellular fragments in the perivitelline space; however, more than 37% of extruded cells were TUNEL negative. We observed no significant difference in embryo quality between expanded blastocysts with and without cellular fragments in the perivitelline space. Overall, our data suggest that embryos extrude abnormal cells to maintain their developmental potential. The presence of fragmented cells is not an indicator of embryo quality.

Endometrial volume measured on the day of embryo transfer is not associated with live birth rates in IVF: A prospective study and review of the literature

OBJECTIVE

To evaluate the effect of endometrial volume (EV) on the live birth rates (LBR)s in fresh or frozen embryo transfer (ET) cycles.

MATERIAL AND METHODS

This is a prospective study including all women who underwent a fresh or frozen single blastocyst transfer between January 2017 and September 2018 in a university affiliated private hospital. Patients with advanced age (>42years), congenital uterine anomalies, endometrial or myometrial abnormalities, those with a difficult ET, those with only poor-quality blastocysts available for transfer, those in whom an optimal 3D TVUS image could not be obtained and those who were lost to follow-up were excluded. Endometrial volume was assessed using Virtual Organ Computer Aided Analysis program immediately prior to ET by two different observers using a standardized technique. The association of ET outcome and EV was evaluated by receiver operating characteristics (ROC) curve and logistic regression analysis.

RESULTS

A total of 142 patients were included in the final analysis. Patients were grouped according the EV percentiles (p); 5thp (1.7 mL), 10thp (2.2 mL), 25thp (2.9 mL), 50thp (4.3 mL) and >75thp (>5.3 mL) groups. ROC curve analysis was not predictive of LBRs, with an AUC (95 % CI) = 0.48 (0.38-0.58). There was no critical threshold, below which pregnancy was unlikely to occur. No significant association was observed between EV and any of the evaluated clinical outcomes.

CONCLUSION(S)

When controlled for potential confounders, EV assessed by 3D TVUS is not a useful tool for predicting pregnancy in single blastocyst ET cycles.

Blastocyst classification systems used in Latin America: is a consensus possible?

OBJECTIVE

To identify different blastocyst classification systems used by embryologists in Latin American countries and evaluate the possibility of establishing a consensus among these countries.

METHODS

An E-mail survey was carried out through the Latin American Network of Assisted Reproduction (REDLARA) aimed at embryologists from assisted reproduction centers in Latin countries.

RESULTS

Sixty surveys were collected from 12 Latin American countries, of which 66.7% had >10years of professional practice as embryologists. Seven different blastocyst classification systems were reported, of which 5 have previously been described in the literature.

CONCLUSION

Although the group of embryologists surveyed use different blastocyst classification systems, most in this group consider that the embryo score system should be unified in their countries as well as in the region.

Obstetric and perinatal outcomes of singletons after single blastocyst transfer: is there any difference according to blastocyst morphology?

A strong correlation between blastocyst morphology and implantation has been shown by many studies. The consequences and effects of assisted reproductive techniques on children's short and long-term health have always been a source of discussion. The obstetric and perinatal outcome of singletons according to blastocyst morphology has rarely been evaluated. The aim of this observational study is to determine whether a relationship exists between blastocyst morphology and obstetric and perinatal outcomes. A total of 799 singleton clinical pregnancies were analysed after transfer of a single fresh blastocyst on day 5 between 2006 and 2013. Blastocysts were divided into four groups based on their morphology on day 5: group 1 = good morphology blastocysts; group 2 = fair morphology blastocysts; group 3 = poor morphology blastocysts and group 4 = early (B1/B2) blastocysts. Obstetric and perinatal outcomes were compared between the four groups. After adjustment for some confounding variables, main obstetric and perinatal outcomes after transfer of blastocysts with poor morphological characteristics were not associated with increased adverse obstetric and perinatal events. Sex ratio was significantly higher in group 1 compared with groups 2, 3 and 4, and in Group 2 compared with Group 3 (P < 0.001) even after adjustment (P < 0.05).

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.

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.

Is the presence of an uncleaved embryo on day 3 a useful predictor of outcomes following day 5 transfer?

PURPOSE

This study aimed to determine whether the presence of an uncleaved embryo on day 3 is predictive of cycle outcome after day 5 transfer (D5 ET).

METHODS

In vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles from January 2013 to November 2014 with D5 ET were analyzed for the presence of at least one uncleaved embryo on day 3 (D3). Each index cycle (n = 70) was compared with two matched control cycles without uncleaved embryos. The main outcome measures included embryo quality, implantation rate, and clinical pregnancy rate.

RESULTS

Fifty-nine of 3896 total embryos in this study were uncleaved on D3 (1.5 %). Cycles with uncleaved embryos had more oocytes retrieved (20.6 vs. 17.5), lower proportions of good quality embryos on D3 (52.4 vs. 66.1 %), and fewer usable embryos (transferred or frozen) on D5 (42.4 vs. 50.8 %). However, there were no significant differences in the incidence of cycles with a positive hCG, or in the rates of implantation, clinical pregnancy, or live birth.

CONCLUSIONS

Although an uncleaved embryo on D3 is associated with reduced conversion of sibling embryos to the blastocyst stage on D5, overall quality of those embryos forming blastocysts is not markedly decreased and clinical outcomes are not compromised.

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.

Morphokinetic parameters using time-lapse technology and day 5 embryo quality: a prospective cohort study

PURPOSE

The aims of this prospective study were to evaluate whether time-lapse parameters can aid in the prediction of day 5 embryo quality and also to assess their discriminatory capacity.

METHODS

In this prospective cohort study, we used time-lapse technology to record specific timings of key events for 380 day 5 blastocysts (originating from 108 patients). Generalized estimating equation regression models were used to evaluate the capacity of these markers to identify a top-quality blastocyst. Multivariable regression models were also constructed, aiming to identify the model with the highest capacity to predict a top-quality blastocyst. The discriminatory capacity of single predictors or composite models was assessed with the use of receiver operating characteristic (ROC) analyses.

RESULTS

Eight significant predictive parameters of a top-quality blastocyst were identified: s3, t6, t7, t8, tM, tSB, tB and tEB. A ROC analysis of the identified parameters found s3 (area under the curve--AUC 0.585, 95 % CI 0.534-0.635) to have the best individual discriminatory capacity to predict a top-quality blastocyst prior to embryo compaction. The parameter tEB (AUC 0.727, 95 % CI 0.675-0.775) was the best predictor regardless of embryo stage. A model containing s3, t8 and tEB showed a slightly increased discriminatory capacity for top-quality blastocyst prediction (AUC 0.748, 95 % CI 0.697-0.794).

CONCLUSIONS

The identified morphokinetic parameters and their cutoffs, albeit of limited clinical value, add to the increasing knowledge concerning the potential predictive markers of a top-quality blastocyst. Additional evidence is necessary before validated time-lapse parameters can be used for embryo selection in IVF laboratories.

A clinically useful simplified blastocyst grading system

The aim of this study was to investigate whether a new simplified blastocyst grading system (A: fully expanded, clear inner cell mass, cohesive trophectoderm; B: not yet expanded, clear inner cell mass, cohesive trophectoderm; C: small inner cell mass ± irregular trophectoderm ± excluded/degenerate cells) was clinically useful. All day-5 single embryo transfers between 15 June 2009 and 29 June 2012 were reviewed. Implantation, clinical pregnancy and live birth rates were related to embryo quality. Five embryologists were asked to grade and decide the clinical fate of 80 images of day-5 embryos on two occasions 4-6 weeks apart. Implantation, clinical pregnancy and live birth rates decreased with deteriorating embryo quality. A highly significant (P < 0.01) difference was observed between the groups. Inter-observer agreement was substantial for grade allocation (K = 0.63) and clinical decision-making (K = 0.66). Intra-observer agreement ranged from substantial (K = 0.71) to almost perfect (K = 0.88) for grade allocation, and was almost perfect for clinical fate determination (K ≥ 0.84). This grading system is quick and easy to use, effectively predicts IVF outcome and has levels of agreement similar to, if not better than, those associated with more complex grading systems.

A quantitative approach to blastocyst quality evaluation: morphometric analysis and related IVF outcomes

PURPOSE

To quantify blastocyst morphologic parameters with a feasible and standardized tool, investigating their predictive value on implantation outcome.

METHOD

The study retrospectively analyzes 124 blastocysts from 75 patients. Quantitative measurements of blastocyst expansion, inner cell mass and trophoectoderm were taken using digital image analysis software.

RESULT(S)

Blastocysts areas were found to be ranging from 11626.2 up to 35076.4 μm(2). The area of an early blastocyst is A ≤ 18500 μm(2) with a mean diameter d = 140 ± 9 μm, and the area of an expanded blastocyst is A ≥ 24000 with d = 190 ± 9 μm. While blastocyst mean area was not related to implantation rate, more expanded blastocysts displayed a significantly higher implantation rate. Trophoectoderm cell number is a predictor of positive outcome: since a higher of cells (25.6 ± 11.3 vs 16.3 ± 12.8) `forming a tightly knit epithelium is prognostic of implantation potential. Conversely, inner cell mass size is significantly related to implantation only in expanded blastocysts (3122.7 ± 739.0 vs. 2978.1 ± 366.0 μm(2)).

CONCLUSION(S)

Evaluation of blastocyst morphology with a digital image system could be a valuable tool to standardize blastocyst grading based on quantitative parameters. Therefore, digital analysis may be helpful in identifying the best blastocyst to transfer.

Uterine flushing with supernatant embryo culture medium in vitrified warmed blastocyst transfer cycles: a randomized controlled trial

PURPOSE

Does transfer of supernatant embryo culture fluid (stimulation of endometrial embryo transfer - SEET) prior to vitrified warmed blastocyst transfer result in better clinical pregnancy and live birth rates than direct vitrified warmed blastocyst transfer?

METHODS

This randomized controlled trial compared SEET group and direct transfer group (control) in 60 women undergoing vitrified warmed blastocyst transfers. The duration of the study was 3 years. The patients were undergoing vitrified warmed blastocyst transfer at university level infertility centre. Sixty women were randomized to SEET (n = 30) or control (n = 30).

RESULTS

Data was available for analysis from all the 30 women in the SEET group and 30 women in the control group. There were no drop outs in the trial. The implantation rate was significantly lower in the SEET group compared to the control group (27 vs. 44 %, P = 0.018). The clinical pregnancy rates were similar in both the groups (47 vs. 53 %) but the live birth rate was also significantly lower in SEET group (23 vs. 50 %, P = 0.03).

LIMITATIONS

The sample size based on clinical pregnancy rates was small and hence not adequately powered to detect differences in live birth rates. Lack of blinding leading to possible bias cannot be ruled out.

CONCLUSION

There was no evidence of an improvement in clinical pregnancy rate following SEET in vitrified warmed blastocyst transfer compared to direct transfer.

Trophectoderm morphology predicts outcomes of pregnancy in vitrified-warmed single-blastocyst transfer cycle in a Chinese population

PURPOSE

In this study, we estimated the effect of blastocoele expansion, ICM and TE quality after warming and culture on the rates of clinical pregnancy, live birth and miscarriage in vitrified-warmed single-blastocyst transfer cycle in a Chinese population.

METHODS

A retrospective analysis of 263 cycles of vitrified-warmed single-blastocyst transfers was performed.

RESULTS

The blastocysts with higher TE grade significantly increased the rates of clinical pregnancy (OR = 0.59, 95 % CI, 0.35-0.99, P = 0.045, grade (A + B) vs grade C) and live birth (OR = 0.55, 95 % CI, 0.32-0.94, P = 0.029, grade (A + B) vs grade C). And the association between TE grade and the rate of live birth didn't change after the number of repeated cycles was adjusted (OR = 0.55, 95 % CI, 0.32-0.95, P = 0.033, grade (A + B) vs grade C). The number of repeated cycles was a confounding factor significantly different between the live birth and no live birth groups. By contrast, neither blastocoele expansion nor inner cell mass was statistically related to the rates of clinical pregnancy, live birth and miscarriage.

CONCLUSIONS

Our data firstly provided the evidence that TE grading, but not ICM grading, was significantly associated with the clinical pregnancy rate and live birth rate in vitrified-warmed blastocyst transfer cycles in a Chinese population. TE morphology may help predict outcomes of pregnancy in single-blastocyst transfer.

Comparison of clinical outcomes following vitrified warmed day 5/6 blastocyst transfers using solid surface methodology with fresh blastocyst transfers

OBJECTIVES:

The literature regarding clinical outcomes following day 5/6 vitrified warmed blastocysts transfer has been conflicting. We decided to evaluate and compare the clinical outcomes following vitrified warmed day 5/6 blastocyst transfer using a solid surface vitrification protocol with fresh blastocyst transfers.

SETTINGS:

University teaching hospital.

STUDY DESIGN:

A total of 249 women were retrospectively analyzed: 146 fresh day 5 blastocyst (group 1), 57 day 5 vitrified warmed blastocyst (group 2), and 46 vitrified warmed day 6 blastocyst (group 3) transfer cycles. Vitrification was done using solid surface methodology (non immersion protocol). The main outcomes were implantation rates, clinical pregnancy, and live birth rate per embryo transfer.

RESULTS:

The baseline clinical characteristics were similar among all three groups. The implantation and clinical pregnancy rates following vitrified warmed day 6 blastocyst transfers (20.9% and 32.6%) were significantly lower as compared to day 5 fresh and vitrified warmed day 5 blastocyst transfers (40.3% and 56.1%, 36.3%, and 52.6%). However, there was no significant difference in the live birth rates across the three groups (group 1: 37.6%, group 2: 40.3%, and group 3: 28.2%).

CONCLUSION:

No statistically significant difference was observed in live birth rates between fresh day 5 blastocyst transfers and vitrified warmed day 5/6 blastocyst transfers. Vitrification of blastocysts using solid surface methodology is an efficient method of cryopreservation.

Morphological systems of human embryo assessment and clinical evidence

Success rates with IVF have improved remarkably since the procedure was first established for clinical use with the first successful birth in 1978. The main goals today are to perform single-embryo transfer in order to prevent multiple pregnancies and achieve higher overall pregnancy rates. However, the ability to identify the most viable embryo in a cohort remains a challenge despite the numerous scoring systems currently in use. Clinicians still depend on developmental rate and morphological assessment using light microscopy as the first-line approach for embryo selection. Active research in the field involves developing non-invasive methods for scoring embryos and ranking them according to their ability to implant and give rise to a healthy birth. Current attention is particularly being focused on time-lapse evaluation. Available data from preliminary studies indicate that these systems are safe;prospective data now need to be collected to determine whether these methods do improve implantation rates. This review gives brief consideration to the use of morphological evaluations in assisted reproduction treatment, discusses the types of embryo scoring,digital imaging and biometric approaches currently in use and comments on future developments for embryo evaluation.

The Istanbul consensus workshop on embryo assessment: proceedings of an expert meeting

BACKGROUND

Many variations in oocyte and embryo grading make inter-laboratory comparisons extremely difficult. This paper reports the proceedings of an international consensus meeting on oocyte and embryo morphology assessment.

METHODS

Background presentations about current practice were given.

RESULTS

The expert panel developed a set of consensus points to define the minimum criteria for oocyte and embryo morphology assessment.

CONCLUSIONS

It is expected that the definition of common terminology and standardization of laboratory practice related to embryo morphology assessment will result in more effective comparisons of treatment outcomes. This document is intended to be referenced as a global consensus to allow standardized reporting of the minimum data set required for the accurate description of embryo development.

Glucose consumption of single post-compaction human embryos is predictive of embryo sex and live birth outcome

BACKGROUND

The aim of this study was to determine the relationship between nutrient utilization by the human embryo and its subsequent viability after transfer. METHODS The embryos of 50 patients having single blastocyst transfer were cultured individually from Day 3 in 10 µl drops of medium G2 under Ovoil in 5%O(2), 6%CO(2), 89%N(2). Patient inclusion in the study was maternal age ≤ 38. Embryos were moved to fresh drops of medium every 24 h. Spent media samples, including controls containing no embryo, were coded, frozen and subsequently analysed blind. Analysis of glucose was performed by microfluorimetry. The sex of children born was recorded.

RESULTS

Clinical pregnancy and live birth rates were 58 and 56%, respectively. Glucose consumption by embryos which resulted in a pregnancy was significantly higher on both Day 4 and Day 5 than that by embryos which failed to develop post-transfer (P < 0.01). Furthermore, on Day 4 female embryos consumed 28% more glucose compared with males (P < 0.05). Glucose uptake was independent of embryo grade.

CONCLUSIONS

The rapid screening of glucose metabolism by the human embryo on Day 4 and 5 may prove to be a useful metric in the development of algorithms for the selection of embryos for transfer in human IVF. Also, the observed sex-related metabolic difference provides preliminary data to support the hypothesis that male and female human embryos differ in their physiology due to the presence of two active X chromosomes and an altered proteome for a finite time during the preimplantation period.

Istanbul consensus workshop on embryo assessment: proceedings of an expert meeting

This paper reports the proceedings of an international consensus meeting on oocyte and embryo morphology assessment. Following background presentations about current practice, the expert panel developed a set of consensus points to define the minimum criteria for oocyte and embryo morphology assessment. It is expected that the definition of common terminology and standardization of laboratory practice related to embryo morphology assessment will result in more effective comparisons of treatment outcomes. This document is intended to be referenced as a global consensus to allow standardized reporting of the minimum dataset required for the accurate description of embryo development. This paper reports the proceedings and outcomes of an international consensus meeting on human oocyte and embryo morphology assessment. An expert panel developed a series of consensus points to define the minimum criteria for such assessments. The definition of common terminology, and standardization of laboratory practices related to these morphological assessments, will permit more effective comparisons of treatment outcomes around the world. This report is intended to be referenced as a global consensus to allow standardized reporting of the minimum descriptive criteria required for routine clinical evaluations of human embryo development in vitro.

A review on automatic analysis of human embryo microscope images

Over the last 30 years the process of in vitro fertilisation (IVF) has evolved considerably, yet the efficiency of this treatment remains relatively poor. The principal challenge faced by doctors and embryologists is the identification of the embryo with the greatest potential for producing a child. Current methods of embryo viability assessment provide only a rough guide to potential. In order to improve the odds of a successful pregnancy it is typical to transfer more than one embryo to the uterus. However, this often results in multiple pregnancies (twins, triplets, etc), which are associated with significantly elevated risks of serious complications. If embryo viability could be assessed more accurately, it would be possible to transfer fewer embryos without negatively impacting IVF pregnancy rates. In order to assist with the identification of viable embryos, several scoring systems based on morphological criteria have been developed. However, these mostly rely on a subjective visual analysis. Automated assessment of morphological features offers the possibility of more accurate quantification of key embryo characteristics and elimination of inter- and intra-observer variation. In this paper, we describe the main embryo scoring systems currently in use and review related works on embryo image analysis that could lead to an automatic and precise grading of embryo quality. We summarise achievements, discuss challenges ahead, and point to some possible future directions in this research field.

Association between amino acid turnover and chromosome aneuploidy during human preimplantation embryo development in vitro

This study investigated the relationship between human preimplantation embryo metabolism and aneuploidy rates during development in vitro. One hundred and eighty-eight fresh and cryopreserved embryos from 59 patients (33.9 +/- 0.6 years) were cultured for 2-5 days. The turnover of 18 amino acids was measured in spent media by high-performance liquid chromatography. Embryos were either fixed for interphase fluorescent in situ hybridization analysis of chromosomes 13, 18, 19, 21, X or Y, or were assayed for mitochondrial activity. Amino acid turnover was different (P < 0.05) between stage-matched fresh and cryopreserved embryos due to blastomere loss following warming. The proportion of embryos with aneuploid cells increased as cell division progressed from pronucleate- (23%) to late cleavage stages (50-70%). Asparagine, glycine and valine turnover was significantly different between uniformly genetically normal and uniformly abnormal embryos on Days 2-3 of culture. By Days 3-4, the profiles of serine, leucine and lysine differed between uniformly euploid versus aneuploid embryos. Gender significantly (P < 0.05) affected the metabolism of tryptophan, leucine and asparagine by cleavage-stage embryos. Pronucleate zygotes had a significantly higher proportion of active:inactive mitochondria compared with cleavage-stage embryos. Furthermore, mitochondrial activity was correlated (P < 0.05) with altered aspartate and glutamine turnover. These results demonstrate the association between the metabolism, cytogenetic composition and health of human embryos in vitro.

Acquiring 3-D information about thick objects from differential interference contrast images using texture extraction

The extraction of 3-D morphological information about thick objects is explored in this work. We extract this information from 3-D differential interference contrast (DIC) images by applying a texture detection method. Texture extraction methods have been successfully used in different applications to study biological samples. A 3-D texture image is obtained by applying a local entropy-based texture extraction method. The use of this method to detect regions of blastocyst mouse embryos that are used in assisted reproduction techniques such as in vitro fertilization is presented as an example. Results demonstrate the potential of using texture detection methods to improve morphological analysis of thick samples, which is relevant to many biomedical and biological studies. Fluorescence and optical quadrature microscope phase images are used for validation.

Elective single embryo transfer: guidelines for practice British Fertility Society and Association of Clinical Embryologists

Assisted conception treatment is the single most important cause in the increase in multiple pregnancy and births over the last 25 years. Multiple births are associated with significant peri natal morbidity and mortality. Europe has led the way in reducing multiple births by widespread adoption of an elective single embryo policy, which in Belgium is linked to an increase in state funding. Randomized controlled trials suggest that an eSET policy must include the ability to cryopreserve and transfer any remaining quality embryos to obtain parity with a double embryo transfer. This document provides a review of the available evidence with guidelines for practice, to help facilitate the introduction of an eSET policy in the UK.

Elective single embryo transfer: a 6-year progressive implementation of 784 single blastocyst transfers and the influence of payment method on patient choice

OBJECTIVE

To evaluate efforts to reduce twin pregnancies through progressive implementation of elective single embryo transfer (eSET) among select patients over a 6-year period.

DESIGN

Retrospective review.

SETTING

Private practice IVF center.

PATIENT(S)

Infertile women undergoing 15,418 consecutive IVF-ET cycles.

INTERVENTION(S)

IVF-ET, including blastocyst-stage eSET among select patients with good prognosis and high risk of multiple pregnancy.

MAIN OUTCOME MEASURE(S)

Pregnancy, multiple pregnancy, method of payment.

RESULT(S)

Pregnancy rates were similar for autologous eSET versus double-blastocyst transfer (65% vs. 63%), while twin rates were much lower (1% vs. 44%). For recipients of donor oocytes, pregnancy rates were slightly lower with eSET (63% vs. 74%), while twin rates were much lower (2% vs. 54%). There was no decrease in overall pregnancy rates, despite a dramatic rise in eSET use over time (1.5% to 8.6% of all autologous transfers and 2.0% to 22.5% of all transfers to donor oocyte recipients between 2002 and 2007). Overall singleton pregnancy rates increased, while twin pregnancy rates declined significantly over time. Use of eSET was significantly more common among patients with insurance coverage or who were participating in our Shared Risk money-back guarantee program.

CONCLUSION(S)

Selective eSET use among good-prognosis patients can significantly reduce twin pregnancies without compromising pregnancy rates. Patients are more likely to choose eSET when freed from financial pressures to transfer multiple embryos.

Phase-subtraction cell-counting method for live mouse embryos beyond the eight-cell stage

Since 1978 in vitro fertilization (IVF) procedures have resulted in the birth of over 3 million babies. Yet in 2005, IVF procedures had a live birth rate of only 34%, with 32% of these births resulting in multiple pregnancies. These multiple pregnancies were directly attributed to the transfer of multiple embryos to increase the probability that a single, healthy embryo was included. The predominantly accepted noninvasive viability markers for embryos created by IVF are (1) number of cells at specific time points during development and (2) overall morphology of the embryo. Currently, it is difficult to count the number of cells beyond the eight-cell stage noninvasively. We report a nontoxic cell-counting method capable of counting cell numbers ranging from 8 to 26 in live mouse embryos. This method is derived from the fusion of differential interference contrast and optical quadrature microscopy and is verified by epifluorescence images of Hoechst-stained nuclei. The phase-subtraction cell-counting method is the first accurate, nontoxic technique to count cells through the morula stage in mouse embryos and may enhance the use of cell number as a viability marker if adopted for use with human embryos in the IVF clinic.

How can we improve current blastocyst grading systems?

PURPOSE OF REVIEW

To give an overview of the current status and future directions of blastocyst transfer and outcome with particular focus on markers of blastocyst quality and their relationship with implantation.

RECENT FINDINGS

In addition to morphological markers, future embryo grading systems, in general, and blastocyst grading systems, in particular, will be based upon metabolic, genetic and epigenetic markers that will increase their efficiency. Metabolic markers such as soluble human leukocyte antigen-G, analysis of specific gene mutations in the trophectoderm by real-time multiplex polymerase chain reaction and analysis by microarray of differential gene expression will be operational in the near future for accurate blastocyst grading and selection.

SUMMARY

Gamete and embryo quality as well as culture conditions affect blastocyst formation and quality. Characteristics of the zygote and the cleavage-stage embryo determine the developmental potential of the embryo up to the blastocyst stage. There appears to be a strong relationship between blastocyst quality and implantation. Accurate grading is important for selection of the most implantation-competent blastocyst. Similar to grading systems used in the cleavage-stage embryo, current blastocyst grading systems are mainly based upon morphological characteristics. Incorporation of metabolic, genetic and epigenetic markers will undoubtedly improve the selection process, making it possible to transfer a single blastocyst yielding high pregnancy rates.