Pregnancy

Development of Embryo and Fetus

As the fertilized egg develops into the baby we see at birth, it goes through three main stages of growth: 1. the stage of the zygote (before implantation), 2. the stage of the embryo (early in the pregnancy), and 3. the stage of the fetus (later in the pregnancy). Since the first of these stages has already been discussed under "Conception", we now turn to a description of how the new organism grows inside the uterus.