Cell exclusions occurring at the 9-cell stage resulted in pregnancy rates comparable to embryos without CE, while exclusions at other stages led to poorer reproductive outcomes.
Does the developmental stage of cell exclusion affect reproductive success in human embryos?
The developmental stage at which cell exclusion occurs, rather than its physical extent, is the primary driver of reproductive competence in affected human embryos.
Absolute Event Rate: 0% vs 0%
Cell exclusion (CE) is a morphological phenomenon observed and characterized relative to embryo morulation, yet its implications for reproductive competence seem heterogeneous. This study investigated whether variability in reproductive success among CE-containing (CE+) embryos could be attributed to differences in the timing and physical extent of cell exclusion, cleavage-stage morphology and morphokinetics. A total of 698 embryos cultured in time-lapse incubators, across two independent fertility clinics, were retrospectively analysed. Embryos were assessed for the presence of CE (CE+, n = 155) prior to fresh embryo transfer and stratified according to the cleavage stage at which excluded cell(s) first appeared. Reproductive success varied markedly across CE+ subgroups, where exclusions at the 9-cell stage (CE+ 9 ) resulted in the highest proportions of FHB and LB, comparable to embryos without CE (CE-, n = 543). Exclusions at the 6-cell (CE+ 6 ), 8-cell (CE+ 8 ), 3-cell (CE+ 3 ) stages, and combination (CE+ C ) exclusions were associated with the poorest outcomes following logistic regression analysis. Neither the number of excluded cells nor the relative surface area occupied by exclusions (%SA) was shown to predict reproductive success, however correlation analysis revealed associations between %SA and various morphokinetic parameters. Routine embryo morphology annotations did not vary between CE+ subgroups. These findings demonstrate that the developmental stage of CE, rather than the extent of exclusion, may represent the primary driver of heterogeneity in reproductive competence among CE+ embryos.
Kakulavarapu et al. (Tue,) reported a other. Cell exclusions occurring at the 9-cell stage resulted in pregnancy rates comparable to embryos without CE, while exclusions at other stages led to poorer reproductive outcomes.