Diverse developmental velocities of blastocyst development emerge as early as a few hours after insemination: morphokinetic analysis of fertilisation in days 4–7 blastocysts
DOI:10.1007/s10815-025-03476-8 by Journal of Assisted Reproduction and Genetics in 2025
[2679]
Animal and vegetal materials of mouse oocytes segregate at first zygotic cleavage: a simple mechanism that makes the two-cell blastomeres differ reciprocally from the start
DOI:10.1093/molehr/gaae045 by Molecular Human Reproduction in 2025
[2644]
Key Points
see Q&A
70
Recent advances in embryology have shown that the sister blastomeres of two-cell mouse and human embryos differ reciprocally in potency
71
Image analysis (in the mouse) revealed that cleavage took place preferentially along the short (i.e. equatorial) diameter of the oocyte, thereby partitioning the animal and vegetal materials into the two-cell blastomeres.
72
Increasing evidence from 2017 onwards has been showing that when mouse blastomeres are separated at the two-cell stage, in most cases, only one blastomere is able to develop into a viable blastocyst or a live mouse
73
It follows that no matter in which region of the ooplasm the spermatozoon may be introduced, whether by ICSI or IVF, the zygote may cleave equatorially more often than previously thought
74
Part of the embryo developmental potential may be determined before fertilization by the shape and contents of the MII oocyte.
75
Removal of an early blastomere (for PGT-a)could have a greater or lesser impact depending on whether that blastomere’s cytoplasm stemmed from the A or V hemisphere of the oocyte
89
1PN blastocysts in patients undergoing by ICSI and 0PN blastocysts by IVF show viable fertility options for patients with abnormal fertilization.
120
The timing of fertilisation events in the cytoplasm and pronuclei (PN) differed among the day 4–7 blastocyst groups from the outset.
121
PB2 extrusion occurred significantly earlier in day 4 blastocysts than in day 5 blastocysts
122
The duration of the cytoplasmic halo was shortened in day 4 blastocysts and prolonged in day 6 blastocysts compared with that in day 5 blastocysts
123
Paternal PN appeared earlier in day 4 blastocysts than in day 5 blastocysts, whereas their appearance was delayed in day 6 blastocysts
ClassRoom
Gamete activation: basic knowledge and clinical applications.
DOI:10.1093/humupd/dmw014 by Human Reproduction Update in 2016
[145]
TextBook
The first mitotic division: a perilous bridge connecting the zygote and the early embryo
DOI:10.1093/humrep/dead067 by Human Reproduction in 2023
[199]
Recent Publications
Diverse developmental velocities of blastocyst development emerge as early as a few hours after insemination: morphokinetic analysis of fertilisation in days 4–7 blastocysts
DOI:10.1007/s10815-025-03476-8 by Journal of Assisted Reproduction and Genetics in 2025
[2679]
Could blastocysts derived from abnormal fertilized zygotes be used? A systematic review and meta-analysis
DOI:10.1016/j.eurox.2025.100381 by European Journal of Obstetrics & Gynecology and Reproductive Biology in 2025
[2666]
Animal and vegetal materials of mouse oocytes segregate at first zygotic cleavage: a simple mechanism that makes the two-cell blastomeres differ reciprocally from the start
DOI:10.1093/molehr/gaae045 by Molecular Human Reproduction in 2025
[2644]
Delays in the final stages of fertilization are strongly associated with trichotomous cytokinesis and cleavage arrest
DOI:10.1007/s10815-024-03330-3 by Journal of Assisted Reproduction and Genetics in 2024
[2381]
Genome folding and zygotic genome activation in mammalian preimplantation embryos
DOI:10.1016/j.gde.2024.102268 by Current Opinion in Genetics & Development in 2024
[2241]
The first two blastomeres contribute unequally to the human embryo.
DOI:10.1016/j.cell.2024.04.029 by Cell in 2024
[990]
IVF Alerts
DNA organisation during first hours of embryo development mapped
