Search

Purpose: To study embryo morphokinetics in relation to release in spent media of molecules with possible roles in development and implantation (miR-20a, miR-30c, and sHLA-G)., Methods: Data were obtained from embryos generated in standard IVF and ICSI cycles. The Eeva system was used for embryo assessment, based on early morphokinetic parameters and producing a score (1-5, best-worst) corresponding to higher/medium/lower chances of development to blastocyst. miRNAs - mm miR-20a-5p and miR-30c-5p - and sHLA-G were quantified in 25 μl of spent blastocyst media (SBM) collected before vitrification or transfer. Statistical analyses were performed applying Kolmogorov-Smirnov, Shapiro-Wilk, and Spearman's correlation coefficient tests, where appropriate., Results: SBM were collected from a total of 172 viable blastocysts. Their analysis showed that concentration of miR-20a was progressively lower as Eeva score increased and probability of development to blastocyst decreased (P = 0.016). The opposite trend was observed in the case of miR-30c, i.e., concentration was higher as score increased and chances of development to blastocyst decreased (P = 0.004). Analysis of sHLA-G revealed a negative correlation with Eeva score, i.e., levels were progressively lower as Eeva score increased and probability of development to blastocyst decreased (R = - 0.388, N = 141, P = 0.001)., Conclusion: Our data suggest that morphokinetic algorithms that predict development to blastocyst stage, in fact, also identify embryos with molecular and cellular profiles more consistent with developmental functions., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Research Question: The morula stage is a poorly understood developmental stage. In the morula, cell compaction can involve all or only some blastomeres, with largely unknown implications. Here, the prevalence, underlying morphokinetic mechanisms and possible consequences of partial compaction, were investigated., Design: Preimplantation genetic testing for aneuploidies (PGT-A) cycles of women whose embryos were observed by time-lapse technology were studied. PGT-A data, generated by array comparative genomic hybridization analysis and assessed in three age groups (≤34, 35-39 and ≥40 years), were obtained from trophectoderm biopsies after development to blastocyst stage., Results: Compaction occurred according to three modalities: (i) full compaction, with all blastomeres included (FCM); partial compaction (partially compacted morula [PCM]), with blastomeres (ii) excluded from the outset (excluded-PCM) or (iii) extruded after compaction (extruded-PCM). Partial compaction occurred more frequently than full compaction. Excluded-PCM displayed the slowest morphokinetics at most stages and were most often associated with abnormal cleavage. After compaction, embryo degeneration was more frequently associated with cell extrusion. In excluded-PCM, loss of ≥2 cells impacted blastocyst rate. In embryos of both younger and middle age groups, no statistical differences were observed in the rate of aneuploidy in relation to the three compaction groups, unlike what observed in ≥40 years women. Implantation rates after transfer of euploid blastocysts were not statistically different between the three groups., Conclusions: Alternative modalities of incomplete compaction were detected. Such patterns are characterized by different morphokinetic behaviours overarching the entire preimplantation development, and by different developmental abilities., (Copyright © 2019 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Preimplantation genetic testing for aneuploidy (PGT-A) is widely used in IVF and aims to improve outcomes by avoiding aneuploid embryo transfers. Chromosomal mosaicism is extremely common in early development and could affect the efficacy of PGT-A by causing incorrect embryo classification. Recent innovations have allowed accurate mosaicism detection in trophectoderm samples taken from blastocysts. However, there is little data concerning the impact of mosaicism on viability, and the optimal clinical pathway for such embryos is unclear. This study provides new information concerning the extent to which mosaic preimplantation embryos are capable of producing pregnancies and births. Archived trophectoderm biopsy specimens from transferred blastocysts were analyzed using next generation sequencing (NGS). Unlike other PGT-A methods, NGS accurately detects mosaicism in embryo biopsies. 44 mosaic blastocysts were identified. Their clinical outcomes were compared to 51 euploid blastocysts, derived from a well-matched, contemporary control group. Mosaic embryos were associated with outcomes that were significantly poorer than those of the control group: implantation 30.1 versus 55.8% (P = 0.038); miscarriage rate 55.6 versus 17.2% (P = 0.036); and ongoing pregnancy 15.4 versus 46.2% (P = 0.003). 61% of the mosaic errors affected whole chromosomes and 39% were segmental aneuploidies. Embryo viability is compromised by the presence of aneuploid cells. However, a minority of affected embryos can produce successful pregnancies. Hence, such embryos should not necessarily be excluded, but given a lower priority for transfer than those that are fully euploid. It is recommended that pregnancies established after mosaic embryo transfers be subjected to prenatal testing, with appropriate patient counselling.