Fetus

A fetus (/ˈfiːtəs/; also spelled foetus, fœtus, faetus, or fætus, see below) is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.

In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization. This article will discuss the etymology of the fetus and its development from weeks 9 to 38. The viability and fetal pain is also a concern. Circulatory system involving postnatal development and the differences from the adult circulatory system will be discussed along with the immune system. Developmental problems and legal issues are up for discussion as well.