The greatest attrition occurs between day 3 and days 5 or 7 (the blastocyst stage). However, not all embryos will reach the blastocyst stage, which represents an embryo with the highest likelihood ...

Researchers stained the cells of a mouse embryo that had its tissue cleared so they could watch its nervous system and blood vessels develop in tandem. This 13.5-day-old embryo, viewed under a ...