The neonatal period is the period from the moment the fetus is delivered from the mother, when the umbilical cord is cut, to 28 days after birth, which is called the neonatal period. For the other stages, infancy is described as the period from birth to 1 week of age. Early childhood: from the age of 1 year to the age of 3 years is the early childhood period. Preschool period: from 3 weeks of age to 6-7 years of age before entering elementary school is the preschool period. School-age period: The school-age period is from the beginning of elementary school (6 to 7 years old) to before puberty. Adolescence: The age range of adolescence is generally from 10 to 20 years old. The early neonatal period refers to the period from birth to one week after the child is born. During this period, the child is separated from the mother and turns to survive independently, and the internal and external environment undergoes fundamental changes, but its adaptive capacity is not yet perfect. Moreover, there are some specific congenital disorders that can manifest themselves at birth, initiating the first challenges in the life of the newborn. At this stage, there will also be a particular sensitivity to some injuries, such as jaundice, where a significant increase in bilirubin in the first week after birth is known to cause kernicterus, which can injure the nervous system. There are also issues such as hypoglycemia, infections, anemia, and breastfeeding that are of particular concern. Therefore, neonatal morbidity and mortality are extremely high during the neonatal period, especially during the first week of life, and need to be closely monitored.