Cleavage-stage stratification reveals the clinical and developmental potential of 0PN embryos compared with 2PN...

Embryo selection remains a critical factor in optimizing outcomes in assisted reproductive technologies (ART). While 2PN embryos are considered the standard for transfer, the clinical potential of 0PN-derived embryos remains controversial. Emerging evidence suggests that cleavage-stage dynamics may play a key role in determining embryo viability.

This retrospective cohort study included 275 IVF cycles, comprising 96 patients in the 0PN group and 179 in the 2PN group. A total of 897 blastocysts were analyzed. Embryos were stratified based on Day-3 cleavage rate into ≤6, 7-9, and ≥10 cell groups. Outcomes assessed included blastocyst development, clinical pregnancy, live birth, and maternal and neonatal outcomes. Statistical analyses were performed using SPSS 25.0.

In both groups, embryos with intermediate cleavage (7-9 cells) demonstrated significantly higher usable and high-quality blastocyst rates (p < 0.05). The 2PN group showed superior clinical pregnancy and live birth rates across all subgroups. However, 0PN embryos with optimal cleavage exhibited clinically meaningful outcomes. No significant differences were observed in neonatal outcomes or adverse maternal events between groups (p > 0.05). Subgroup analysis suggested a non-significant trend toward slightly higher risk in certain outcomes in the 0PN group. Cleavage-stage dynamics emerged as a key determinant of embryo competence, independent of fertilization status. Although 2PN embryos remained superior overall, selected 0PN-derived blastocysts showed measurable developmental and clinical potential. However, the absence of significant short-term maternal or neonatal differences should be interpreted cautiously because of the limited number of 0PN live births, lack of genetic validation, and short follow-up period.

Selected 0PN-derived blastocysts with optimal cleavage characteristics showed measurable developmental and clinical potential; however, because of limited subgroup sample sizes and insufficient power to detect uncommon adverse outcomes, these findings should be interpreted as exploratory and require validation in larger, multicenter prospective studies.