The neonatal period is the first 4 weeks of a child's life. It is a time when changes are very rapid. Many critical events can occur in this period: Feeding patterns are established. Bonding between parents and infant begin
Before the baby is born, blood goes through the placenta to get rid of waste and to pick up oxygen and nutrients that come from the mother. The developing baby manages on relatively low oxygen levels while in the uterus. After birth the child is exposed to suddenly higher (potentially dangerous) oxygen levels
hope that helped!