Winston N J
Laboratoire de Physiologie du Developpement, Institut Jacques Monod, CNRS-Université Paris VII, France.
Int Rev Cytol. 1996;164:139-88. doi: 10.1016/s0074-7696(08)62386-4.
The majority of human conceptuses fertilized normally in vitro fail to establish a pregnancy following their replacement in utero. However, since conceptuses are usually transferred after only one or two cell divisions, their developmental outcome is not known. It has been found that a significant number of human oocytes which can be fertilized carry chromosomal abnormalities, even in the absence of ovarian stimulation. After fertilization, preimplantation-stage conceptuses developing in vitro display a high incidence of cellular abnormalities. Similar disruptions of cellular organization have also been noted in conceptuses fertilized in vivo. Thus, developmental abnormalities and the demise of the conceptus prior to the stage of implantation may stem from the poor quality of the oocyte. The conditions encountered in vitro have also been proposed to cause or contribute to the early demise of human conceptuses.
大多数在体外正常受精的人类受精卵在子宫内着床后无法成功妊娠。然而，由于受精卵通常在仅进行一两次细胞分裂后就被移植，其发育结果尚不清楚。已经发现，即使在没有卵巢刺激的情况下，大量能够受精的人类卵母细胞也携带染色体异常。受精后，在体外发育的植入前阶段受精卵显示出细胞异常的高发生率。在体内受精的受精卵中也观察到了类似的细胞组织破坏。因此，植入前阶段受精卵的发育异常和死亡可能源于卵母细胞质量差。也有人提出，体外环境会导致或促成人类受精卵的早期死亡。
