The Prenatal Developmental Period

• Prenatal development (from Latin natalis, meaning ‘relating to birth’) includes the development of the embryo and of the fetus during a viviparous animal’s gestation.
• In human pregnancy, prenatal development is also called antenatal development.
• Prenatal development is highly influenced by the inheritance, expression, and regulation of genes.
• The development of a human from fertilization of an oocyte to birth is divided into two main periods:

(a) Embryonic period and

(b) Fetal period.