High Implantation Potential Research Articles

The clinical use of time-lapse in human-assisted reproduction.

A major challenge in the assisted reproduction laboratory is to set up reproducible and efficient criteria to identify the embryo with the highest developmental potential. Over the years, several methods have been used worldwide with this purpose. Initially, standard morphology assessment was the only available strategy. It is now universally recognized that besides being a very subjective embryo selection strategy, morphology evaluation alone has a very poor prognostic value. More recently, the availability of time-lapse incubators allowed a continuous monitoring of human embryo development. This technology has spread quickly and many fertility clinics over the world produced a remarkable amount of data. To date, however, a general consensus on which variables, or combination of variables, should play a central role in embryo selection is still lacking. Many confounding factors, concerning both patient features and clinical and biological procedures, have been observed to influence embryo development. In addition, several studies have reported unexpected positive outcomes, even in the presence of abnormal developmental criteria. While it does not seem that time-lapse technology is ready to entirely replace the more invasive preimplantation genetic testing in identifying the embryo with the highest implantation potential, it is certainly true that its application is rapidly growing, becoming progressively more accurate. Studies involving artificial intelligence and deep-learning models as well as combining morphokinetic with other non-invasive markers of embryo development, are currently ongoing, raising hopes for its successful applicability for clinical purpose in the near future. The present review mainly focuses on data published starting from the first decade of 2000, when time-lapse technology was introduced as a routine clinical practice in the infertility centers.

Automatic grading of human blastocysts from time-lapse imaging

Background:Blastocyst morphology is a predictive marker for implantation success of in vitro fertilized human embryos. Morphology grading is therefore commonly used to select the embryo with the highest implantation potential. One of the challenges, however, is that morphology grading can be highly subjective when performed manually by embryologists. Grading systems generally discretize a continuous scale of low to high score, resulting in floating and unclear boundaries between grading categories. Manual annotations therefore suffer from large inter-and intra-observer variances. Method:In this paper, we propose a method based on deep learning to automatically grade the morphological appearance of human blastocysts from time-lapse imaging. A convolutional neural network is trained to jointly predict inner cell mass (ICM) and trophectoderm (TE) grades from a single image frame, and a recurrent neural network is applied on top to incorporate temporal information of the expanding blastocysts from multiple frames. Results:Results showed that the method achieved above human-level accuracies when evaluated on majority votes from an independent test set labeled by multiple embryologists. Furthermore, when evaluating implantation rates for embryos grouped by morphology grades, human embryologists and our method had a similar correlation between predicted embryo quality and pregnancy outcome. Conclusions:The proposed method has shown improved performance of predicting ICM and TE grades on human blastocysts when utilizing temporal information available with time-lapse imaging. The algorithm is considered at least on par with human embryologists on quality estimation, as it performed better than the average human embryologist at ICM and TE prediction and provided a slightly better correlation between predicted embryo quality and implantability than human embryologists.

Embryo culture in step single and sequential media: influence on morphology and implantation potential of blastocysts

Purpose. To assess the impact of step single and sequential culture media on the morphology and frequency of blastocyst implantation. Materials and methods. In total, 514 embryos obtained from patients aged 30 to 35 years and fertilized by ICSI were studied (2017 to 2018). The pool of embryos from each woman was randomly divided into two groups: the first group was cultured in the sequential media and the second - in the single ones. Evaluation of the effect was carried out by comparing the obtained blastocysts quality cultured in the single and sequential media. Blastocyst morphology was assessed using the modified Gardner D. K. scale. Statistical analysis was performed by Mann–Whitney U-test and Pearson's chi-squared test with Yates' correction. Statistically significant differences between the compared groups were considered at P < 0.05. Results. The studies found that the use of single Origio ® 1-Step medium at embryo culture phase improves the morphological quality of the resulting blastocyst compared to embryos cultured in sequential Origio ® Sequential Cleav™ / Sequential Blast™ media. No statistically significant difference in the pregnancy and implantation rate of blastocysts obtained after embryo cultivation in the step single or sequential media was detected. Conclusions. The priority in terms of obtaining a large number of high quality blastocysts with high implantation potential is to use a step single medium for the embryo cultivation.

A deep learning framework outperforms embryologists in selecting day 5 euploid blastocysts with the highest implantation potential

A deep learning framework outperforms embryologists in selecting day 5 euploid blastocysts with the highest implantation potential

Optimising the Outcome of Embryo Transfer

In vitro fertilisation (IVF) is a complex procedure, the success of which is dependent on several factors at every step of the process. Despite major advances, successful implantation rates in IVF remain low. Aside from the status of the embryo and endometrium, embryo transfer (ET) plays a major role in implantation. There are numerous variables in ET that are causative factors for IVF success. In this article, the authors discuss whether the stage at which (cleavage versus blastocyst) ET occurs; a fresh or frozen ET; and the technique of ET affects the results of an assisted reproductive technology cycle. Blastocysts had higher implantation potential than cleavage-stage embryos and it was also observed that extended embryo culture was not related to increased adverse obstetric and perinatal outcome. Though freezing has several advantages over fresh cycles, one must remember that evidence is still lacking for its use in all patients. Elective cryopreservation of all embryos with transfer in subsequent frozen ET cycles may be requited in cases at risk of developing ovarian hyperstimulation syndrome, women undergoing preimplantation genetic screening or preimplantation genetic diagnosis for genetic analysis, polycystic ovarian syndrome patients, and those who have high progesterone levels on the day of human chorionic gonadotropin, but to date it is debatable whether a freeze-all strategy will benefit normal and poor responders. For an optimal ET technique, the use of soft catheters and performing the process under ultrasound guidance will improve results by making it less traumatic, standardised across centres, and more technically precise.

5. EUPLOID BLASTOCYSTS HAVE SIMILAR CLINICAL OUTCOME REGARDLESS OF THEIR D5 KIDSCORE™

Introduction Time-lapse monitoring (TLM) uses morphokinetics assessment and annotation models such as KIDScore™ to help predict the implantation potential of a blastocyst. Meanwhile, preimplantation Genetic Testing for Aneuploidy (PGT-A) determines the chromosomal status of an embryo, allowing the identification of embryos with the correct number of chromosomes. Theoretically, combining both of these advanced technologies in IVF may enable the selection of a competent blastocyst for transfer, thus maximising the chance of a successful pregnancy. To the best of our knowledge, the significance of KIDScore™ annotation model in euploid blastocysts has not been studied. This is a retrospective study to assess the clinical outcomes of elective frozen embryo transfer (eFET) of euploid blastocysts in various D5 KIDScore™ groups in Alpha Fertility Centre, Malaysia, between January to November 2018. Material and Methods Two hundred and twenty-one (221) patients aged 18 – 45 years (mean age 30.8 years) had their embryos cultured to blastocyst stage in the Embryoscope™ incubator (Vitrolife, Sweden) and screened using Next Generation Sequencing (Ion Torrent, USA). In order to accurately determine the D5 KIDScore™ of the euploid blastocysts transferred, only blastocysts intended for single frozen embryo transfer were included in this study. All the 221 blastocysts transferred were categorised according to D5 KIDScore™ ranged between 1.0 – 4.0 (Group A, n = 4), 4.1 – 5.0 (Group B, n = 4), 5.1 – 6.0 (Group C, n = 15), 6.1 – 7.0 (Group D, n = 49), 7.1 – 8.0 (Group E, n = 83), 8.1 – 9.0 (Group F, n = 53), and 9.1 – 9.9 (Group G, n = 13) respectively. Clinical pregnancy and number of gestational sacs were determined by ultrasound. Results The clinical pregnancy rates and implantation rates for Group A, B, C, D, E, F and G were 25.0%, 75.0%, 66.7%, 46.9%, 60.2%, 60.4% and 53.8% respectively. The miscarriage rates for Group A, B, C, D, E, F and G were 0.0%, 33.3%, 20.0%, 4.3%, 6.0%, 12.5% and 14.3% respectively. There was no significant difference in clinical pregnancy rate, implantation rate and miscarriage rate between all groups (p>0.05). Conclusions Our study shows no significant difference in clinical pregnancy rate, implantation rate and miscarriage rate across all D5 KIDScore™ groups for euploid blastocysts. Euploid blastocysts with lower D5 KIDScore™ gives comparable clinical outcomes of that to blastocyst with higher D5 KIDScore™ and should be considered in the selection for transfer. D5 KIDScore™ may serve as a guide for selection of blastocyst with high implantation potential. However, PGT-A still remains the more reliable method compared to solely relying on D5 KIDScore™ in TLM for blastocyst selection. Nevertheless, further studies with a larger sample size should be carried out to ascertain the significance of D5 KIDScore™ in blastocyst that was screened euploid using PGT-A.

NON-INVASIVE PGT-A WITH THE ANALYSIS OF EMBRYONIC CELL FREE DNA IN SPENT BLASTOCYST MEDIA

The success of assisted reproduction treatments is based on the selection of the best embryos for transfer, those with the highest implantation potential and ongoing pregnancy rates: euploids. The most reliable method to assess the chromosomal status of preimplantation embryos is preimplantation genetic testing for aneuploidies (PGT-A). Other options such as morphology and morphokinetics are not good candidates to replace PGT-A techniques as their correlation with embryo ploidy is weak. However, biopsy-based approaches on PGT-A entail both technical and economic challenges as embryo manipulation is needed and it could affect viability. To avoid those limitations, non-invasive methods based on the analysis of the cell-free DNA released by the embryo during the latest stages of preimplantation development has been proposed. In the last years there have been different attempts to overcome trophectoderm biopsy to diagnose the chromosomal content of the embryos. Some groups started with the analysis of blastocoel fluid obtained by aspiration with a thin micropipette as a less invasive approach than TE biopsy. Later on, some groups proposed a “true” non-invasive approach consisting in the study of the spent culture media to analyse the embryonic cell free DNA (cfDNA) released by the embryo during the latest stages of preimplantation development. After the first publications, several studies have compared the results of PGT-A in TE biopsies with the results of the spent culture media, to establish the concordance rates among both approaches. In these studies, the percentages of informative samples vary widely, likely reflecting the existence of mosaicism and/or presence of DNA from granulosa, cumulus cells or polar bodies in the spent blastocyst media (SBM) urging the need for technical improvements before this new non-invasive technology can be clinically applied. We have conducted a pilot study comparing aneuploidy testing using a non-invasive approach to trophectoderm biopsy, advancing one step towards understanding the potential value of niPGT-A. With the incorporation of a non-invasive approach, we aimed to address the two main limitations of current PGT-A, namely invasiveness and diagnosis of mosaicism, as only 5-8 cells are retrieved from the whole blastocyst in a TE biopsy. Regarding clinical outcomes, we have followed-up data on a subset of patients after SET performed according to TE biopsy results and compared the clinical outcome retrospectively according to cfDNA results. Interestingly, ongoing implantation rates were three-times higher when both TE and cfDNA were euploid, than in euploid TE paired with aneuploid cfDNA indicating that embryonic cfDNA might open a new avenue for the understanding of embryo ploidy. The origin of embryonic cfDNA is still unclear. Also, examining the mechanisms implicated in the secretion of cfDNA to the media is challenging.

A Strength, Weaknesses, Opportunities and Threats analysis on time lapse.

The study of embryonic development through conventional microscopy has contributed significantly to the success of IVF. However, clinical pregnancy rates per transfer remain as low as 30% according to the latest records of European society if human reproduction and society if assisted reproduction. Considering the increased need to reduce the number of multiple pregnancies, the embryologist is required to improve embryo selection methods to reduce the number of embryos transferred and identify those with the highest implantation potential. This represents a big challenge considering that applying this strategy could jeopardize the overall success rates. New strategies have been proposed including the use of time-lapse systems among others. Although this technology has been used for a decade in IVF labs controversies still exist regarding its potential to substitute conventional morphology for embryo evaluation. Lately, different algorithms have been developed correlating embryo kinetics to blastocyst formation, implantation potential, chromosomal content and live birth rate. Moreover, automation and the use of artificial intelligence have recently been introduced to improve this technology. The present review describes the time-lapse technology and the models available, using a Strength, Weaknesses, Opportunities and Threats analysis based on the clinical experience and published data since 2010.

Application of the Pronuclear Scoring System for Predicting the Morphology and Ploidy of Early Human Embryos

The efficiency of in vitro fertilization and embryo transfers into human uteri is low, because approximately 50% of embryos transferred into the uterine cavity are capable to continue their development. This situation has generated the problem of early diagnosis of embryo potential at the stage preceding the selection of morphologically and chromosomally good quality blastocysts. The fertilization quality was assessed 16–18 h after an intracytoplasmic sperm injection (ICSI) micromanipulation by the presence of pronuclei using Z-scores. We examined the size and the location of pronuclei relative to the cell center, the number of nucleoli, and their distribution. The best development and, respectively, the highest implantation potential were demonstrated by embryos developed from zygotes of the Z1 category. Zygotes Z2 and Z3 also formed AA quality blastocysts on day 5. None of the fertilized oocytes forming zygote Z4 developed into a viable embryo. We have established differences in the capability to form AA quality blastocysts between zygotes of categories Z1, Z2, and Z3 and the category Z4 as well as between categories Z1 and Z3. It has been found that the highest number of embryos in which the number of the studied chromosomes corresponded to the norm was formed from zygotes of Z1 and Z2 categories, and a significant difference in the number of embryos in which aneuploidy has not been diagnosed has been found in embryos formed from zygotes of Z1, Z2, and Z3 categories compared with type Z4 zygotes.

Day 7 blastocyst euploidy supports routine implementation for cycles using preimplantation genetic testing.

Objective:To determine if Day 7 blastocysts merit biopsy, vitrification and transfer consideration by contrasting their aneuploidy and implantation rates to Day 5 and 6 blastocysts.Methods:A total of 1,925 blastocysts were biopsied from 402 PGT-A cycles over a 12 to 16 month interval. All embryos were cultured under tri-gas, humidified conditions (37ºC) for up to 7 days (168 hours post-insemination). Biopsied blastocysts were vitrified and trophectoderm samples analyzed using NextGen sequencing. Single euploid embryo transfers were performed (n=254) using either a Day 5 (n=145), Day 6 (n=92) or a Day 7 blastocyst (n=16) post-warming. Euploidy rates and pregnancy outcomes were subsequently assessed and differences determined by day of development and blastocyst quality grade.Results:No differences were observed in implantation, pregnancy loss or ongoing pregnancy rates between Day 5 and Day 6 blastocysts. Development to Day 7 accounted for 6.6% of all blastocysts. Euploidy rates were higher in Day 5 blastocysts (53.5%; p<0.05) compared to Day 6 (40.4%) and Day 7 (35.9%). High implantation potential (56.3% to 79.3%) of vitrified-warmed euploid blastocyst occurred independent to the day of development. However, miscarriage/loss rates increased (22.2% vs. 2%; p<0.05) with Day 7 blastocysts, resulting in lower (p<0.05) live birth rates (43.8% vs. 67.4-77.2%).Conclusion:Culturing blastocysts to Day 7 has proven beneficial by achieving viable euploid embryos that would have otherwise been discarded. An extra Day of embryo growth allows select patients additional opportunities for in vitro development and possible healthy term live births.

Case report: Pregnancy After Vitrification of Biopsied Human Blastocysts Previously Frozen by the Slow Method

Pre-implantation genetic screening (PGS) with trophectoderm biopsy is an extremely powerful technique for the determination of embryos with a high implantation potential. Patients with cryopreserved embryos seeking PGS have had limited access to this treatment due to the need to thaw, biopsy, and refreeze these embryos. This is especially true for patients with embryos cryopreserved by the slow freeze technique due to the low survival rate after thawing. In this case report, we describe the application of refreezing with the vitrification technique to embryos thawed with the slow technique and biopsied for PGS. The patient had a total of 8 blastocysts thawed, biopsied, and refrozen with vitrification. Next Generation Sequencing (NGS) of these embryos revealed that 4 blastocysts were euploid. The patients achieved a pregnancy on the the first frozen embryo transfer procedure that terminated after 11 days. The second frozen embryo transfer procedure resulted in the live birth of a 3800g boy, demonstrating that thaw, biopsy, and refreeze are applicable to human reproduction even in cases where embryos have been cryopreserved by the slow technique

Larger size of the oocyte cohort does not affect risk of embryo aneuploidy when using next generation sequencing (NGS)

Recent advances in comprehensive chromosomal screening technology with NGS, have enhanced our ability to identify euploid embryos with high implantation potential 1,2. Embryos with lower potential for live birth containing aneuploidy or mosaicism, are discarded or reserved. Given this improved ability of NGS to detect the number of normal embryos developing from a single cohort of oocytes, we sought to evaluate whether oocyte retrieval yield, number of mature oocytes, or number of blastocyts biopsied, correlates with euploidy rate. Retrospective cohort study. 477 in vitro fertilization (IVF) cycles performed at a large university-based center during a three-year period were evaluated. IVF cycles with planned preimplantation genetic testing (PGT) performed using NGS were included for analysis. PGT results were reported as euploid, aneuploid or mosaic. Patients were divided into approximately equal groups based on number of oocytes retrieved, number of mature oocytes, and number of blastocysts biopsied. Patients were further stratified by age according to SART criteria. The primary outcome was rate of euploid embryos per cohort. Continuous variables were evaluated using Student’s t-test and ANOVA with Tukey’s multiple comparison test. Chi-square was used to assess categorical variables. Multivariate logistical regression was performed to control for potential confounding variables. Euploidy rates differed based on number of oocytes retrieved (1-5: 23.9%, 6-10: 26.2%, 11-15: 29.5%, >16: 35.4%; p=0.03), number of mature oocytes (1-5: 19.1%, 6-10: 30.4%, 11-15: 32.6%, >16: 36.1%; p<0.01), and number of embryos biopsied (1-2: 24.3%, 3-4: 29.7%, 5-8: 35.8%, >9: 35.0%; p<0.01). After performing multivariate linear regression to control for potential confounding factors, no association between increasing oocyte yield and euploidy was appreciated (p=0.59). Similar findings were noted when analyzing euploidy rates by the number of mature oocytes (p=0.07) and embryos biopsied (p=0.43). After stratifying by age, only patients in the 38-41yo cohort were found to have higher rates of euploidy when more than 10 oocytes were retrieved, with a trend towards higher rates in the younger groups (Table). Euploidy rate is not adversely affected when more oocytes are retrieved when measured within age strata. With the advent of Leuprolide trigger, reliable cryopreservation, and FET, this finding will likely lead us to more aggressive ovarian stimulation protocols, increase the odds of a euploid blastocyst, and maximize the chance of live birth with a single ovarian stimulation.TableAge & Euploidy Rates by Number of Oocytes RetrievedAge Groups (yrs)<3535-3738-41>41Oocytes Retrieved≤10 ≥11≤10 ≥11≤10 ≥11≤10 ≥11% Euploidy36.1 47.841.2 46.219.2 28.915.9 10.9Bold: p<0.05 Open table in a new tab

Euploid embryos selected by an automated time-lapse system have superior SET outcomes than selected solely by conventional morphology assessment.

We investigated if automated TLI selection may be a valuable strategy to identify those euploid embryos with the best chances of success. This is a unicentric and retrospective study involving 244 patients undergoing preimplantational genetic screening (PGS) cycles with autologous oocytes or oocyte donation (OD) with single euploid embryo transferred. We examined euploid embryos selected for transfer based on morphology evaluation alone (PGS-only; control group) or by assessment using an automated TLI system (Eeva™; PGS-TLI group). In both, autologous oocytes and OD patients, significantly better implantation and clinical and ongoing pregnancy rates were obtained in the PGS-TLI group when euploid embryos with high implantation potential as predicted by the automated TLI System (Eeva™) were transferred compared with the PGS-only group. This improvement was also observed when only transfers of good morphological quality embryos were compared. TLI categories showed significant differences on blastocyst formation and euploidy rate. Automated TLI combined with PGS is a useful prognostic tool to identify euploid embryos with the highest potential for implantation and pregnancy. Further, these results provide evidence that a healthy pregnancy does not only depend upon normal chromosomal status.

How general semen quality influences the blastocyst formation rate: Analysis of 4205 IVF cycles.

ObjectiveTo select embryos with higher implantation potential, the extended culture has been the most frequently applied strategy worldwide, and consequently leads to higher live birth rates per transfer. Sperm quality is a determining feature, and it may influence the outcomes of IVF from fertilization to embryo development. Therefore, we hypothesize that blastocyst formation may also be impaired by general semen quality.MethodsWe analyzed 4205 IVF cycles. Four study groups were designed according to semen quality: normal, mild alteration, severe alteration and epididymis. All cycles were intended to extend embryo culture until the blastocyst stage, and embryo development was evaluated.ResultsRegarding cleavage rate, the normal and mild alteration semen groups were equivalent, and the severe alteration and epididymis semen groups were equivalent to each other. The blastocyst formation rate decreased with semen quality. At least one blastocyst formed in 79.9% of cycles for the normal semen group, whereas the percentage of cycles with the formation of at least one blastocyst was slightly lower for the mild alteration (75.6%), severe alteration (76.4%) and epididymis (76.8%) semen groups. A multivariate logistic regression showed that for each additional cleaved embryo on day 3, the chance of having at least one blastocyst doubles. Additionally, the chance of having at least one blastocyst decreased when semen presented mild or severe alterations.ConclusionThe general quality of sperm is a good predictor of blastocyst formation, significantly affecting the likelihood of having at least one blastocyst at the end of the cycle. Based on our findings, it is necessary to consider general semen quality and the number of cleaved embryos when forecasting the possibility of blastocyst formation and transfer in an extended culture system.

Investigation of the Developmental Potential and Developmental Kinetics of Bovine Parthenogenetic and Somatic Cell Nuclear Transfer Embryos Using a Time-Lapse Monitoring System.

A time-lapse monitoring system has predictive value for selecting good-quality embryos with the highest implantation potential. Using this new tool, we investigated the developmental potential and developmental kinetics of bovine parthenogenetic (PA) and two types of somatic cell nuclear transfer (NT) embryos. Bovine non-transgenic ear cells (bECs) or transgenic cells (bTGCs) were used as donor cells. The cleavage and blastocyst development rates did not significantly differ among the PA, NT-bEC, and NT-bTGC groups, and first cleavage occurred an average of 19.3 hours (n = 70), 21.6 hours (n = 60), and 21.3 hours (n = 62) after activation, respectively (20.4 hours [n = 192] for all embryos). When embryos were classified into early cleaving (≤20 hours) and late cleaving (>20 hours) groups, the blastocyst formation rate was much higher in the early cleaving groups (PA, 46%; NT-bEC, 50%; NT-bTGC, 39%) than in the late cleaving groups (PA, 18%; NT-bEC, 23%; NT-bTGC, 28%), while the percentage of embryos whose development was blocked between the two- and eight-cell stages was increased in the late cleaving groups. The percentage of embryos classified as early cleaving with a normal morphology was twofold higher in the PA group (20.0%, n = 14) than in the NT-bTGC group (9.7%, n = 6). The timing of each developmental stage varied widely; the timing of first cleavage varied from 7.6 hours in the PA group to 34.5 hours in the NT-bEC group and the timing of expanded/hatching blastocyst appearance varied from 141.6 hours in the PA group to 196.3 hours in the NT-bTGC group, differences of 26.9 and 54.7 hours, respectively (PA>NT-bEC>NT-bTGC). These results demonstrate that time-lapse monitoring provides novel data regarding individual embryo developmental kinetics and helps to predict developmental potential for improved bovine NT embryo selection based on early cleavage (≤20 hours) and normal morphology.

Selection of human blastocysts with a high implantation potential based on timely compaction.

Recently, we established a noninvasive system for selecting human blastocysts with a high pre-transfer implantation potential based on first and second division patterns. The present study was carried out to improve the selection system. Embryos that completed first and second divisions within 25.90 and 37.88h after culture, respectively, were selected using a time-lapse incubator. We examined the effects of compaction and blastocyst formation times on pregnancy rates after transferring these embryos at the blastocyst stage. The completion of compaction and blastocyst formation times (79.93 and 97.47h after culture, respectively) of embryos resulting in pregnancies after transfer were significantly (P<0.01) shorter than those (86.46 and 100.34h after culture, respectively) of embryos that failed to induce pregnancies. Embryo selection based on completion of compaction time improved pregnancy rates (40.9 vs. 74.6%, P<0.01). Of the embryos that formed two cells during the first division within 25.90h after culture and four cells during the second division within 37.88h after culture, those that completed compaction within 79.93h after culture before reaching the blastocyst stage had a high implantation potential.

Selecting embryos with the highest implantation potential using data mining and decision tree based on classical embryo morphology and morphokinetics.

The objective of this work was to determine which embryonic morphokinetic parameters up to D3 of in vitro development have predictive value forimplantation for the selection of embryos for transfer in clinical practice based upon information generated from embryo transfers with known implantation data (KID). A total of 800 KID embryos (100% implantation rate (IR) per transfer and 0% IR per transfer) cultured in an incubator with Time-Lapse system were retrospectively analysed. Of them, 140 embryos implanted, whereas 660 did not. The analysis of morphokinetic parameters, together with the embryo morphology assessment on D3, enabled us to develop a hierarchical model that places the classical morphological score, the t4 and t8 morphokinetic values, as the variables with the best prognosis of implantation. In our decision tree, the classical morphological score is the most predictive parameter. Among embryos with better morphological scores, morphokinetics permits deselection of embryos with the lowest implantation potential.

Blastocyst transfer is not associated with increased unfavorable obstetric and perinatal outcomes compared with cleavage-stage embryo transfer

Background: Recent studies demonstrated controversial results of whether there are risks in fetal outcomes after blastocyst-stage embryos transfer (BT) compared with cleavage-stage embryos transfer (CT). Aims: To compare the implantation rates (IR), clinical pregnancy rates (cPR), birth rates (BR), gestational weeks, preterm birth rates, birth weights and low birth weight rates between CT and BT groups. Methods: A retrospective study of 1627 embryos transfer cycles was performed from May 2014 to April 2015. The cycles were divided into two groups according to transfer stage: CT on Day 3 (n = 798) and BT on Day 5 (n = 829). For the CT group, it must have surplus embryos and only surplus embryos developed to available blastocysts, the cleavage-stage embryos could be included. The clinical outcomes of two groups were analyzed. Results: The IR in CT group was lower than BT group (48.98% vs. 60.68%; p < 0.01). There were no significant differences in the clinical pregnancy rate and birth rate between BT and CT groups. For singletons and twin deliveries, there were no significant differences in gestational weeks, preterm birth rates, birth weights and low birth weight rates between two groups. Conclusion: Blastocysts had higher implantation potential than cleavage-stage embryos. Extended embryo culture was not related to increased adverse obstetric and perinatal outcome.

Embriones multinucleados: criterios para la transferencia

IntroductionMultinucleation is a common phenomenon in in vitro human embryos and is associated with a poor outcome. Time-lapse monitoring of embryo development allows a continuous and detailed observation of fertilisation and cleavage events. An evaluation is presented on the impact of the presence of multinucleation on embryo morphokinetics, developmental ability, and implantation potential. Material and methodsA retrospective cohort study was conducted on a total of 5540 embryos cultured in a TL system (Embryoscope®, Unisense Fertilitech®) from 763 ICSI cycles performed between 2012 and 2014. Presence of multinucleation in all developmental stages was assessed. Embryo replacement was performed on D+3. Multinucleated embryos were cultured to the blastocyst stage and cryopreserved for subsequent transfer. ResultsApproximately one quarter (23.6%) of the studied embryos showed multinucleation. Multinucleated embryos showed altered morphokinetic parameters compared to the non-multinucleated ones. The multinucleated embryos that reached the blastocyst stage (18%) were cryopreserved. No differences in the developmental ability were observed compared to the multinucleated type or percentage of multinucleated cells. There was a 39.1% implantation rate of the blastocysts obtained from multinucleated embryos. DiscussionTime-lapse monitoring of embryo development allows a better detection of the multinucleation phenomenon. The presence of multinucleated cells is associated with changes in the morphokinetics and a reduced developmental ability. However, multinucleated embryos that reach the blastocyst stage can be replaced, and have a high implantation potential.

Predictive value of spindle retardance in embryo implantation rate.

We evaluated the relationship between meiotic spindle characteristics and in vitro fertilization cycle outcome. Five hundred sixty-nine oocytes from 86 in vitro fertilization cycles were analyzed for fertilization and subsequent implantation rates. Oocytes were assessed for maturation status. The oocytes and embryos were cultured in sequential and nonsequential media (G Series, Vitrolife, Sweden) and incubated in 6% CO2, 5% O2 at 37°C. Two hours following oocyte decumulation (38-39h post-hCG/GnRH administration) and prior to microinjection, the structure of the meiotic spindle was assessed using the Oosight Imaging System (CRI, UK). Four hundred fifty-six oocytes (80.5%) had a visible meiotic spindle, 82 (14.7%) had no meiotic spindle, and 31 (5.5%) were in telophase I. Oocytes exhibiting a meiotic spindle had a significantly higher fertilization rate and a lower rate of abnormal fertilization. Implantation data were obtained for 195 of the embryos transferred. The implantation rate for embryos derived from oocytes with a meiotic spindle was 32.9%, while in embryos originating from oocytes without a meiotic spindle and oocytes in telophase, this value dropped significantly (8.8 and 0%, respectively). To determine the correlation between retardance values and implantation rate for each oocyte, we established four groups, finding a range of retardance values with significantly higher implantation rates (27.5, 21, 29.3, and 53.8%, respectively). Meiotic spindle imaging may be a valuable tool for prediction of oocyte quality, and retardance values of meiotic spindles, together with classical morphological classification, can be useful to select embryos with a higher implantation potential.