Blastocyst score, a blastocyst quality ranking tool, is a predictor of blastocyst ploidy and implantation potential

Abstract

Objective: To convert blastocyst (BL) morphological grade and BL day into a numeric blastocyst score (BS). Design: Retrospective cohort study. Setting: Academic center. Patient(s): A total of 5,653 BL of known implantation (fetal heart, FH) and 11,348 biopsied BL. Intervention(s): Based on their FH rates and/or significance, a score (1-4) was assigned to each BL grade component. The BL morphological score (BMS) is the sum (BS ¼ BMS on day 5; BS ¼ BMS þ 2 on day 6). Main Outcome Measure(s): Statistics characterized the FH and euploidy odds with BS. Result(s): All three morphology grade components and BL day were associated with implantation and euploidy probability. The FH rate and euploidy odds decrease with larger BS. The BS was the most important factor (odds ratio [OR] per unit change ¼ 0.807, 95% confidence interval [CI] 0.784, 0.831) for untested and euploid BL implantation, and the sole one for euploid BL (OR/unit change ¼ 0.845, 95% CI 0.803, 0.889). The BS is the second most significant factor after maternal age for euploidy probability (OR/unit change ¼ 0.808, 95% CI 0.795, 0.822). In training and validation sets (75:25), the BS can predict implantation with similar area under the curve [AUC] (training ¼ 0.628, 95% CI 0.613, 0.643; validation ¼ 0.606, 95% CI 0.581, 0.631). The BS has better euploidy prediction ability (training AUC ¼ 0.683, 95% CI 0.673, 0.693; validation AUC ¼ 0.698, 95% CI 0.681, 0.715). The BS can stratify BL into good (3-5), fair (6-9), and poor (10-14) groups, reflecting their FH, live birth rates, and ploidy status. Advanced maternal age was associated with lower untested BL implantation and lower euploidy odds across all groups. Conclusion(s): The BS is a predictor of BL ploidy and FH implantation. (Fertil Steril Rep Ò 2020;1:133-41. Ó2020 by American Society for Reproductive Medicine.

Artificial intelligence in the embryology laboratory: a review

“…More complex and detailed BL grading systems correlate very well with implantation potential and ploidy assessment. In their recent paper, Zhan et al converted alphanumeric BL grades into a numeric score for use in statistical analysis and correlations (Zhan et al, 2020a). By using AI, we might be able to strengthen the correlation between BL assessment and outcome in a more objective manner.…”

“…However, its invasive nature, cost, and the assumption of diagnostic accuracy limit a more widespread use. It is no surprise that noninvasive approaches for embryo selection including time-lapse morphokinetic evaluation (Campbell et al, 2013), morphology assessment (Capalbo et al, 2014;Zhan et al, 2020b), and AI systems (Pennetta et al, 2018;Meyer et al, 2020) have aimed to compare PGT-a outcomes against their findings. However, it is still difficult to find studies presenting AI systems for embryo ranking that are trained against ploidy status as their ground truth.…”

Bayesian Network Modeling of IVF Blastocyst Score Prediction

“…Obtaining many embryos is possible at each cycle of the IVF treatment; however, generally, the three highest quality embryos are transferred to the woman's uterus. Multiple embryo transfers increase the pregnancy probability, but they also increase potential complications of multiple pregnancies (Gerris & De Neubourg, 2005;Irmawati et al, 2019;Martikainen et al, 2004;Thurin et al, 2004;Veleva et al, 2006) Thus, it is aimed to maximize success rates with single embryo transfers by improving embryo selection (Zhan et al, 2020).…”

Blastocyst Morphology Based on Uniform Time-Point Assessments is Correlated With Mosaic Levels in Embryos

“…Numerous experimental studies have delineated a link between blastocyst morphology and chromosomal abnormalities ( Alfarawati et al, 2011 ; Capalbo et al, 2014 ; Minasi et al, 2016 ; Barash et al, 2017 ; Wang et al, 2018 ; Zhan et al, 2020 ). Individual morphological components of blastocyst evaluation, that is, expansion degrees, inner cell mass (ICM) grades, and trophectoderm (TE) grades, may be correlated with the ploidy status independently ( Minasi et al, 2016 ; Zhan et al, 2020 ). The combination of expansion, ICM, and TE grades could therefore result in complication for ranking the embryos.…”

“…Thus, several studies have combined morphological components to categorize blastocysts based on quality ( Capalbo et al, 2014 ; Wirleitner et al, 2016 ) and have even considered the blastocyst biopsy day and morphological features for generating a blastocyst score ( Zhan et al, 2020 ). Although these modified approaches demonstrate that blastocyst morphology is highly associated with its ploidy ( Capalbo et al, 2014 ; Zhan et al, 2020 ), embryo grading variability may occur due to multiple reasons, such as subjective judgments of individual embryologists, laboratory settings, and observation time windows. One of the advantages of TL monitoring is objectively and accurately defined observation time after insemination or ICSI.…”