Growth and development include not only the physical changes that occur from infancy to adolescence but also some of the changes in emotions, personality, behavior, thinking and speech that children develop as they begin to understand and interact with the world around them.

A child’s growth and development can be divided into four periods:

• Infancy
• Preschool years
• Middle childhood years
• Adolescence

By age 4 to 6 months, an infant’s weight should be double their birth weight. During the second half of the first year of life, growth is not as rapid. Between ages 1 and 2, a toddler will gain only about 5 pounds (2.2 kilograms). Weight gain will remain at about 5 pounds (2.2 kilograms) per year between ages 2 to 5.