Inter- and Intra-Observer Agreement Between Embryologists for Cytoplasmic String Assessment in Day 5/6 Human Blastocysts.

To investigate inter- and intra-observer agreement in the assessment of cytoplasmic string (CS) by embryologists on day 5/6 human blastocysts using the EmbryoViewer software. This was a prospective study involving five embryologists working between 2019 and 2020. Inter-observer agreement was calculated using assessments performed on 104 day 5/6 blastocysts regarding the presence, number, and location of CS and CS vesicle activity using timelapse videos. Intra-observer agreement was calculated when the same embryologists repeated the observations after a month's break. Inter- and intra-observer agreement was assessed using Fleiss' kappa coefficient and the intra-class correlation coefficient (ICC). The inter-observer agreement on the presence of CS (kappa: 0.477, 95% CI: 0.301-0.639) and their vesicles (kappa: 0.494, 95% CI: 0.345-0.643) was moderate, while the specific characteristics of CS assessment ranged from fair to moderate (kappa scores between: 0.157 and 0.563). The intra-observer agreement indicated an improvement on the level of agreement (kappa scores between: 0.162 and 0.795) compared to the inter-observer agreement. This study has shown a moderate level of inter- and intra-observer agreement when assessing day 5/6 human blastocysts for the presence of CS and their vesicles. When the specific characteristics of CS assessment occurred (such as the number of CS/vesicles) a slight to moderate level of agreement was seen among the embryologists. Agreement of specific characteristics of CS was not optimal, suggesting the need for further training using specifically designed CS quality assurance programme (QAP) modules, to determine if inter- and intra-observer agreement can be improved.

Detailed analysis of cytoplasmic strings in human blastocysts: new insights.

The aim of this study was to determine if there was an association between the presence of cytoplasmic strings (CS) and their characteristics, with blastocyst quality, development and clinical outcome in human blastocysts. This two-centre cohort study was performed between July 2017 and September 2018 and involved a total of 1152 blastocysts from 225 patients undergoing in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). All embryos were cultured in Embryoscope+ and were assessed for CS using time-lapse images. A single assessor examined all blastocysts and reviewed videos using the EmbyroViewer® Software. Blastocyst quality was assessed on day 5 of embryo development. The number of CS, location and duration of their activity was recorded on days 5/6. A positive association between the presence of CS in human blastocysts with blastocyst quality was identified. Blastocysts with a higher number of CS present, were of higher quality and were in the more advanced stages of development. Top quality blastocysts had CS activity present for longer, as well as having a higher number of vesicles present travelling along the CS. Blastocysts that had CS present, had a significantly higher live birth rate. This study has confirmed that a higher number of CS and vesicles in human blastocysts is associated with top quality blastocysts and is not a negative predictor of development. They had a higher number of CS present that appeared earlier in development and, although ceased activity sooner, had a longer duration of activity. Blastocysts with CS had a significant increase in live birth rate.

The presence of cytoplasmic strings in human blastocysts is associated with the probability of clinical pregnancy with fetal heart.

PURPOSE: Is the presence of cytoplasmic strings (CS) in human blastocysts associated with the probability of clinical pregnancy with fetal heart (CPFH) after transfer. METHODS: This case-control study involved 300 single blastocyst transfers. 150 of these resulted in a CPFH (cases) while 150 did not (controls). All embryos were cultured in Embryoscope+ and AI software (IVY) was used to select the blastocyst with the highest score from the cohort for transfer. An embryologist, blind to the transfer outcome, recorded the CS number, location, and duration of their activity. RESULTS: There was a significant difference in the number of blastocysts that contained CS, with 97.3% of women's blastocysts resulting in +CPFH containing the CS compared to 88.7% of blastocysts in women who did not have a pregnancy (p = 0.007, OR; 4.67, CI 95% 1.5-14.2). CS appeared 2.4 h earlier in embryo development in the +CPFH group compared to their negative counterparts (p = 0.007). There was a significant difference in the average number of CS/blastocyst with a higher number being present in those that achieved a clinical pregnancy (mean: 6.2, SD 2.9) compared to those that did not (mean: 4.6, SD 3.0) (p ≤ 0.0001). There was a significant increase in the number of vesicles seen traveling along the CS with more seen in the blastocysts resulting in a +CPFH (mean: 4.3 SD 2.1) compared to those in the -CPFH group (mean: 3.1, SD 2.1). CONCLUSION: This study has shown that the presence of cytoplasmic strings in human blastocysts is associated with the probability of clinical pregnancy with fetal heart.

Is early embryo development as observed by time-lapse microscopy dependent on whether fresh or frozen sperm was used for ICSI? A cohort study.

PURPOSE: The aim of this study was to compare timings of key events of embryo development from those originating from either fresh or cryopreserved ejaculate sperm using time-lapse technology. METHODS: In this retrospective observational cohort study, time-lapse technology was used to monitor 1927 embryos from 234 women undergoing intracytoplasmic sperm injection (ICSI) and utilizing either fresh (n = 172 cycles) or cryopreserved ejaculate sperm (n = 62 cycles) for insemination were included in the study. Key developmental events as described in time-lapse were compared with the use of generalized estimating equations (GEE) to adjust for any auto-correlation between the observations. In addition, multivariable logit regression models were used to account for any known baseline differences between the two groups. RESULTS: There were no differences in conventional embryo development such as number of 8-cell embryos by 72 h (p = 0.359), the number of blastocysts by 120 h (p = 0.417), and the number of top quality blastocysts (p = 0.956) between the two groups compared. There were no statistical differences in the timings of any of the key embryo developmental events (PN_t1, NEBD, cytokinesis, t2, t3, t4, t5, t6, t7, t8, tM, tSB, tEB, tHB, s1, s2, s3, cc2, and cc3) when either fresh or cryopreserved ejaculate sperm was used for ICSI. This was also confirmed with conventional morphological assessment. CONCLUSIONS: This observational cohort study has shown that there are no differences in the morphokinetic parameters of early embryo development when either fresh or frozen ejaculate sperm are used for ICSI insemination.