Can 'abnormally' fertilized zygotes give rise to viable embryos?
Can 'abnormally' fertilized zygotes give rise to viable embryos?
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DOI：
10.1080/14647270600636269
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发表时间：
2006-09-01
期刊：
影响因子：
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通讯作者：
Herbert, Mary
中科院分区：
文献类型：
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作者：
Feenan, Katie;Herbert, Mary
体外受精或卵浆内单精子注射的常规做法是根据其形态和卵裂状态从一组受精卵母细胞中选择最优质的胚胎，这些卵母细胞在受精检查时观察到两个原核。然而，在一小部分周期中，选择仅限于在受精检查时看起来未受精（显示零原核）或异常受精（显示一个或三个原核）的胚胎。对于是否应该将这些胚胎移植到子宫中，目前还缺乏共识。单原核卵母细胞胚胎的细胞遗传学分析表明，有一部分是二倍体。这种胚胎的移植导致了健康的出生。有限的细胞遗传学分析表明，尽管在受精检查中没有原核，但仍有一部分卵母细胞具有正常的细胞遗传学结构。具有三个原核的卵母细胞胚胎的细胞遗传学分析显示三倍体率高，细胞分裂混乱。随后的胎儿有极其不利的结果。在这里，我们回顾了已发表的关于“未受精”和“异常受精”胚胎的细胞遗传学分析的文献，并讨论了导致它们形成的可能途径。有限的证据表明，在某些情况下，具有一个原核的卵母细胞和尽管没有原核但仍显示正常向前分裂的卵母细胞可以考虑更换。
Conventional practice in in vitro fertilization or intracytoplasmic sperm injection is to select the best quality embryos based on their morphology and cleavage status from a cohort of fertilized oocytes in which two pronuclei were observed at the time they were checked for fertilization. However, in a small proportion of cycles, the selection is limited to embryos that appeared to be either unfertilized (displaying zero pronuclei) or abnormally fertilized (displaying one or three pronuclei) at the time they were checked for fertilization. There is a lack of consensus on whether such embryos should be transferred to the uterus. Cytogenetic analysis of embryos from oocytes with one pronucleus has shown a proportion is diploid. Transfer of such embryos has resulted in healthy births. Limited cytogenetic analysis of oocytes that divide despite the absence of pronuclei at fertilization check indicates that a proportion also have a normal cytogenetic constitution. Cytogenetic analysis of embryos from oocytes with three pronuclei has shown high rates of triploidy and chaotic cell divisions. Subsequent foetuses have extremely unfavourable outcomes. Here, we review the published literature on the cytogenetic analysis of 'unfertilized' and 'abnormally fertilized' embryos and discuss possible pathways which lead to their formation. The limited evidence indicates that oocytes with one pronucleus and oocytes that show normal onward division despite the absence of pronuclei may be considered for replacement in certain circumstances.