After fertilization occurs in the womb, the fetus will continue to develop from month to month. The development of the fetus every month is different, both in terms of size, body organs that are formed, and physical abilities. Understanding fetal development is expected to help ensure the condition of his health. In the first four weeks of pregnancy, you may not feel any symptoms. The only sign of pregnancy that you might feel is that your period is late. Although symptoms in early pregnancy are rarely felt, the fetus in the womb has begun to develop since conception. Fetal Development in the First Trimester The following stages of fetal development in the first trimester of pregnancy or the first three months: First month After fertilization, the initial stages of embryonic development are zygotes. Zygotes will go to the uterus and form morula, which are groups of cells that look like raspberries. Furthermore, morula will go through several stages of embryonic development.