%0 Journal Article
%T Formation of the first plane of division relative to the pronuclear axis predicts embryonic ploidy.
%A Mizobe Y
%A Kuwatsuru Y
%A Kuroki Y
%A Fukumoto Y
%A Tokudome M
%A Moewaki H
%A Orita Y
%A Iwakawa T
%A Takeuchi K
%J Reprod Biomed Online
%V 49
%N 3
%D 2024 Sep 13
%M 38968730
%F 4.567
%R 10.1016/j.rbmo.2024.104110
%X <B>OBJECTIVE: </B>Is there a relationship between the pronuclear axis and the first cleavage plane formation in human pronuclear-stage embryos, and what are the effects on ploidy and clinical pregnancy rates?<BR><B>METHODS: </B>Transferred embryos were followed up until their prognoses. A total of 762 embryos formed two cells and reached the blastocyst stage after normal fertilization in a time-lapse incubator. Embryos were classified into three groups: group A: embryos in which the first plane of division was formed parallel to the axis of the pronucleus; group B: embryos in which cases of oblique formation were observed; and group C: embryos in which cases of perpendicular formation were observed.<BR><B>RESULTS: </B>The euploidy rate was significantly higher in groups A and B than those in group C (P < 0.01), whereas the aneuploidy rate was significantly higher in group C (P < 0.01) than in groups A and B. No differences were found between the three groups in frequency of positive HCG-based pregnancy tests, frequency of clinical pregnancies, miscarriage rates or delivery rates.<BR><B>CONCLUSIONS: </B>The formation pattern of the first plane of division relative to the pronuclear axis was a predictor of embryonic ploidy, with a reduced rate of euploidy and a high probability of aneuploidy observed when the first plane of division was perpendicular to the pronuclear axis.