The pregnancy period usually takes between thirty-five to forty weeks, which is the normal period before birth and is nine months as God Almighty mentioned in his dear book, but there are mothers who give birth before this period ends, and this varies according to the mother’s body, and during pregnancy the fetus passes by several Stages, and there are several notable changes in it every week, which are similar changes among most fetuses, but they are different in their results, and in this article we will present the developments of fetuses week by week and we will follow the stages of their development