GROWTH AND DEVELOPMENT

Physical growth is rapid during infancy. After birth, there is a period of relative starvation as the infant adjusts to en-teral feeding. Typically, infants lose approximately 5% to 10% of their birth weight, but within days, they begin to gain weight, and by 2 weeks, they are back to birth weight. Average birth weight for a term newborn is 3000 to 4000 g, and this weight usually is doubled by 6 months and tripled by approximately 1 year after birth.

The median height at birth is 49.9 cm for girls and 50.5 cm for boys. During the first 6 months, height in­creases by 2.5 cm per month. By 1 year, the increase in length is 50% of the birth length. This increase is primar­ily in trunk growth. Median head circumference at birth is 34.5 cm for girls and 34.8 cm for boys. The skull bones of newborn infants are incomplete and are connected by bands of connective tissue called sutures. At the junction of the sutures are wider spaces of unossified membranous tissue called fontanels. The larger anterior fontanel is pal­pable until about 18 months to 2 years of age; the smaller

INFANCY

>- Infancy, which is the time from birth to 18 months of age, is a period of rapid physical growth and maturation.

>- From an average birth weight of 3000 to 4000 g in the full-term infant and a median height of 49.9 cm for girls and 50.5 cm for boys, the infant manages to triple its weight and increase its length by 50% at 1 year of age.

>- Developmentally, the infant begins life with a number of primitive reflexes and little body control. By 18 months, a child is able to run, grasp and manipulate objects, feed himself/herself, play with toys, and communicate with others.

>■ Basic trust, the first of Erikson's psychosocial stages, devel­ops as infants learn that basic needs are met regularly.

>- At the age of 18 months or the end of the infancy period, the emergence of symbolic thought causes a reorganiza­tion of behaviors with implications for the many develop­mental domains that lie ahead as the child moves to the early childhood stage of development.