Final answer:
A newborn is classified as a neonate up to four weeks after birth. From the 29th day to the first birthday, the child is considered an infant, marking a significant milestone in development and pediatrics.
Step-by-step explanation:
A newborn transitions to being an infant at the end of the neonatal period, which is four weeks after birth. In medical coding, and according to pediatric classifications, a newborn, or neonate, is defined as a child from birth until 28 days old. After this period, from the 29th day until the first birthday, the child is referred to as an infant. This distinction is important for various reasons, including medical care, developmental assessments, and nutritional requirements.
At birth, a baby's umbilical cord is cut, leading to the eventual formation of the navel as the stub dries and falls off. Newborns are assessed for health based on several traits such as skin color and heart rate. The neonatal stage is a critical time of adaptation during which newborns begin to adjust to life outside the womb. They start to breathe air, establish feeding patterns, and must maintain body temperature outside the controlled environment of the uterus.
Distinguishing between a neonate and an infant is also essential for tracking developmental milestones. Infants undergo rapid growth in the first year, including motor, sensory, and cognitive development. By the end of the first year, infants typically begin to stand with support and may start walking; they can also understand simple commands and might say a few words. The term infancy encompasses this entire period of rapid development, from neonate transitioning at 4-weeks old to the end of the twelfth month. The transition from newborn to infant marks a significant phase in a child's growth and is a defining moment in pediatric healthcare.