Extreme emotional deprivation can interfere with the production of growth hormone, thereby stunting children's growth. Sleep difficulties, in the form of night waking and nightmares, are common during the preschool years. Appetite declines due to a slower rate of physical growth. Since caloric intake is reduced, preschoolers need a high-quality diet. Disease can lead to malnutrition, seriously undermining children's growth, an effect that is especially common in developing countries.
Unintentional injuries are the leading cause of childhood death.
Efforts at several levels, including laws that promote safety, improvement of community environments, and efforts to change parents' and children's behavior, are necessary. An explosion of new motor skills takes place in early childhood. Gross motor skills such as running, jumping, throwing, and catching appear and become better coordinated. Gains in fine motor development can be seen in preschoolers' ability to dress themselves, draw representational pictures, and print letters of the alphabet. As in other areas, heredity and environment combine to influence early childhood motor development.