DEVELOPMENTAL COMPETENCE OF ONE PRONUCLEAR ZYGOTE GENERATED BY INTRA-CYTOPLASMIC SPERM INJECTION AND CULTURED USING A TIME-LAPSE SYSTEM
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Abstract
Objectives: To compare cleavage rates, blastulation rates, and embryo quality between 1 pronuclear (PN) and 2PN zygotes obtained from ICSI cycles and cultured in a time-lapse system. Methods: A retrospective study was conducted on 126 1PN zygotes and 898 2PN zygotes derived from 110 couples undergoing in vitro fertilization (IVF) at the IVFTA Center, Tam Anh General Hospital, Ha Noi, from May 2022 to September 2024. Results: On day 3, the cleavage rate of 1PN zygotes was significantly lower than that of 2PN zygotes (88.9% vs. 98.9%; p < 0.001). Among embryos reaching day 3, the proportion of good-quality embryos was markedly lower in the 1PN group compared with the 2PN group (31.3% vs. 58.9%, p < 0.001). Blastulation occurred at a significantly lower rate in 1PN-derived embryos (21.4%) than in 2PN-derived embryos (67.1%, p < 0.001). Blastocyst quality was comparable between the two groups, with good-quality blastocysts observed in 50.0% of the 1PN group and 52.2% of the 2PN group. Conclusion: 1PN zygotes demonstrate reduced cleavage and blastocyst formation rates compared with 2PN zygotes. However, 1 PN zygotes that progress to the blastocyst stage retain the potential to develop into good-quality embryos.
Keywords
1 pronuclear zygotes, Cleavage rate, Blastulation rate, Time-lapse system
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References
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