Morphokinetic behavior of euploid and aneuploid embryos analyzed by time-lapse in embryoscope

Abstract

BACKGROUND:Embryonic aneuploidy may result in miscarriage, implantation failure, or birth defects. Thus, it is clinically necessary to avoid the selection of aneuploid embryos during in vitro fertilization treatment.AIM:The aim of this study was to identify the morphokinetic differences by analyzing the development of euploid and aneuploid embryos using a time-lapse technology. We also checked the accuracy of a previously described model for selection of euploid embryos based on morphokinetics in our study population.MATERIALS AND METHODS:It is a retrospective study of 29 cycles undergoing preimplantation genetic screening from October 2013 to April 2015 at our center. Of 253 embryos, 167 suitable for biopsy embryos were analyzed for their chromosomal status using array-comparative genome hybridization (CGH). The morphokinetic behavior of these embryos was further analyzed in embryoscope using time-lapse technology.RESULTS:Among the analyzed embryos, 41 had normal and 126 had abnormal chromosome content. No significant difference in morphokinetics was found between euploid and aneuploid embryos. The percentage of embryos with blastulation was similar in the euploid (65.85%, 27/41) and aneuploid (60.31%, 76/126) embryos (P = 0.76). Although hard to define, majority of the chromosomal defects might be due to meiotic errors. On applying embryo selection model from Basile et al., embryos falling within optimal ranges for time to division to 5 cells (t5), time period of the third cell cycle (CC3), and time from 2 cell division to 5 cell division (t5-t2) exhibited greater proportion of normal embryos than those falling outside the optimal ranges (28.6%, 25.9%, and 26.7% vs. 17.5%, 20.8%, and 14.3%).CONCLUSION:Keeping a track of time interval between two stages can help us recognize aneuploid embryos at an earlier stage and prevent their selection of transfer. However, it cannot be used as a substitute for array CGH to select euploid embryos for transfer.

Time-lapse imaging reveals delayed development of embryos carrying unbalanced chromosomal translocations

“…Importantly, the time of division to 5 cells (t5), the duration of the second cell cycle (cc2), and the synchrony of the second and third cell divisions (s2) were found [18] to be significantly correlated with embryo implantation; however, only the median value of s2 was significantly longer in the non-implanting embryos compared with implanting embryos. In contrast, other groups observed no differences between euploid and aneuploid embryos during those early stages of development, although aneuploid embryos had a significant delay in development compared with euploid embryos in the peri-blastulation phase [20,29,30] . Several studies reported that the tSB and formation of a full blastocele were delayed in aneuploid embryos compared with euploid embryos [20,29,30].…”

Controversies in ART: can the IVF laboratory influence preimplantation embryo aneuploidy?

“…Preliminary data altering pH e during different stages of human embryo culture has been shown to impact post-cleavage preimplantation embryo morphokinetic timings (Adolfsson et al, 2016). While mitotic cleavage timings themselves did not appear to be significantly impacted in the study, existing data indicate a possible correlation between embryo morphokinetics and aneuploidy Huang et al, 2019;Kramer et al, 2014;Montag, 2013;Patel et al, 2016;Swain, 2013).…”

“…Varying temperature by even 0.5°C over an extended period of time certainly impacts mitosis and morphokinetic cell timings, as demonstrated in mouse embryos (Walters et al, 2018) ( FIGURE 3). Morphokinetic timings have been correlated with embryo aneuploidy Kramer et al, 2014;Montag, 2013;Patel et al, 2016;Swain, 2013). This could imply that temperature could be impacting chromosome dynamics in the preimplantation embryo.…”

Time-lapse imaging of cleavage divisions in embryo quality assessment

“…Embryos with t5-t2 longer than 20 h or with cc3 longer than 10 h were almost twice more likely to be euploid than embryos with t5-t2 or cc3 shorter than these threshold times (Chawla et al 2015). Patel et al (2016), on the other hand, showed that although embryos having t5-t2 and cc3 parameters inside the optimal range proposed by Basile et al (2014) are more likely to be euploid than embryos with those parameters outside the range, the differences were not statistically significant. The t5-t2 parameter, this time combined with the t3 variable, has also been used in a hierarchical algorithm proposed by Del Carmen Nogales et al (2016).…”

“…Depending on whether the parameter value fits within or outside this range, the prediction is more or less positive. Such algorithms are often used in IVF practice and their reliability has been repeatedly reported (Meseguer et al 2011, Basile & Meseguer 2012, Cruz et al 2012, VerMilyea et al 2014, Del Carmen Nogales et al 2016, Motato et al 2016, Patel et al 2016. However, they have some disadvantages.…”