A newborn infant, or Neonate, is a child under 28 days of age. The newborn period is the most vulnerable time in a child's life. During these first 28 days of life, the child is at highest risk of dying. 

More than 4 million infants die each year worldwide. Approximately two-thirds of infant deaths occur during the first month of life, making the first days of a child's life critical to its survival and future health. 

The immediate causes of newborn death include infection, complications related to premature birth, birth asphyxia, and congenital anomalies. Poor maternal nutrition, maternal reproductive tract infections, low birthweight, and access to health services also contribute to newborn deaths. Many of these conditions can easily be prevented or treated. 

It is thus crucial that appropriate feeding and care are provided during this period, both to improve the child's chances of survival and to lay the foundations for a healthy life.