废弃胚胎的标准

Evaluation of discarded embryos

在体外受精-胚胎移植（IVF—ET）技术中，人类的配子和胚胎存在大量浪费的现象，如约20％的卵子受精失败、约35％的胚胎被直接作为废弃胚胎而丢弃、约60％胚胎在体外培养过程中不能发育到囊胚。即使胚胎被移植入子宫，也是大部分不能着床。人类胚胎的低利用率除了与超排卵、体外培养、胚胎评估选择方法和内膜接受性等有关外，还与人类自身的生理相关。

The standard of discarded embryos is not unified, due to the inability of the analysis of embryo morphology alone to distinguish viable and nonviable embryos. Embryos with poor morphology may have certain development potential, while good morphology is not the guarantee of pregnancy. There is no doubt that embryos with chromosomal abnormalities have no development potential and should be discarded. However, almost half blastocysts have chromosome abnormalities after detection by array CGH. Therefore, more rigorous methods to detect chromosomal status are expecting. Alternative non-invasive techniques have been proposed which may be able to detect alterations of the culture environment surrounding embryos. One of the most recently applied approaches is to measure metabolomic changes in the culture medium. Advance in time-lapse observation technology also make full monitoring embryos possible. Although the results of these initial investigations are promising, further prospective studies are required to define clearly the potential benefits and most relevant applications of this novel non-invasive technology in the field of assisted reproduction.