During the first three years, children are constantly growing and acquiring new skills and knowledge. Surveillance systems have shown that injury is the leading threat to the health and well-being of young children.

Mobile infants have more control of their head, torso, arms, and legs. They also begin to coordinate those movements. At this age, they sleep less and are more active during the day, eager to engage in everything around them.

Infants depend on their families for food, warmth, and care, and for meeting such basic needs as eating, diapering, sleeping, bonding, and safety. But all babies are unique. Some infants may settle easily and be capable of quickly soothing themselves.

The toddler years are a time when children are building skills in all areas. They remember what they learn and share it with others. They understand things more deeply, make choices, and engage with others in new ways.