How long after fertilization does an embryo become a fetus?

An embryo becomes a fetus at around 8 weeks after fertilization. This stage marks a significant transition in prenatal development. During the first 8 weeks of pregnancy, the developing organism is referred to as an embryo, where essential structures and organs begin to form. By the end of this period, most major body systems have started to develop, and the features that will characterize the fetus emerge.

At 8 weeks, the embryo transitions into the fetal stage, which can be identified as a time when the body continues to grow and mature the systems that were established earlier. This period is critical for the refinement and functional development of organs, setting the foundation for growth and development until birth. Thus, recognizing 8 weeks as the point of transition from embryo to fetus helps in understanding the milestones in prenatal development.