Spontaneous blastocyst collapse as an embryo marker of low pregnancy outcome: A Time-Lapse study

Abstract

Objective: In this study we investigate the correlation between spontaneous blastocyst collapse and pregnancy outcome. Methods: This is a retrospective study performed at Edinburgh Assisted Conception Programme, EFREC, Royal Infirmary of Edinburgh, UK. Embryos were cultured individually in 6.0% CO 2 , 5.0% O 2 , 89.0% N 2 , using single step medium (GTL™ Vitrolife, Göteborg, Sweden) and selected for transfer using standard morphological criteria. Using the EmbryoScope™ time-lapse monitoring (TLM), blastocysts collapse was analyzed by measuring the maximum volume reduction and defined as having collapsed if there was >50% volume reduction. Couples undergoing IVF/ICSI treatment and having an elective single embryo transfer (eSET) at blastocyst stage were included in this study. After the embryo transfer, retrospectively, each blastocyst was allocated to one of two groups (collapsed or not collapsed). 62 blastocysts collapsed once or more during development (17.4%), the remaining 294 showed no collapse (82.6%). Results: A significantly higher implantation rate (IR) of 61.2% and ongoing pregnancy rate (OPR) of 53.7% was observed when blastocysts which had not collapsed were replaced compared to cycles in which collapsed blastocysts were replaced (IR rate 22.6% and OPR 17.7%). Conclusion: This study demonstrated that human blastocysts which collapse spontaneously during in vitro development are less likely to implant and generate a pregnancy compared with embryos which do not. Although this is a retrospective study, the results establish the utility of collapse episodes as new marker of embryo selection following eSET at blastocyst stage.

Arrdc4‐dependent extracellular vesicle biogenesis is required for sperm maturation

“…Interestingly, treatment of sperm with the EV‐enriched fractions showed an intriguing effect on subsequent blastocyst development (Figure S6). During hatching from the zona pellucida, blastocysts undergo weak contractions and pulsations, however a stronger collapse is correlated with poor implantation success (Marcos et al, 2015; Niimura, 2003; Sciorio et al, 2020). The decrease in the incidence and number of collapses in blastocysts from the EV 100K treated sperm suggests they may be beneficial to embryo quality.…”

p38-MAPK mediated rRNA processing and translation regulation enables PrE differentiation during mouse blastocyst maturation

“…The in vitro imaging of maturing mouse blastocysts (E3.5-E4.5) reveals phases of pulse-like oscillations in blastocyst and consequently blastocoel cavity volume expansion and contraction, that in the clinic are often used as reporters of blastocyst viability in assisted reproductive technologies 27,28 . Having established reduced blastocyst cavity volume as a phenotype of p38-MAPKi in fixed embryos, we asked if the phenotype is marked by a failure to undergo such pulse-like oscillations.…”

Ochratoxin A affects oocyte maturation and subsequent embryo developmental dynamics in the juvenile sheep model

“…Moreover, OTA-treated blastocysts showed impressive collapse events, with total volume reduction of more than 50%, not observed in control blastocysts, which exhibited regular physiological contractions. In human, blastocyst collapse is strongly related to lower implantation rate (Marcos et al 2015 ) and pregnancy rate (Sciorio et al 2019 ). These considerations are in agreement with the reported increased post-implantation resorption after exposure of oocytes to OTA during IVM (Huang and Chan 2014 ).…”