Infant - newborn development

SENSORY DEVELOPMENT

Vision -- the newborn infant can see within a range of 8-12 inches, color vision develops between 4-6 months, by 2 months can track moving objects up to 180 degrees, and prefers faces.

Hearing -- begins prior to birth, and is mature at birth. The infant prefers frequencies of the human voice.

Touch, taste, smell -- mature at birth; prefers sweet taste.

Vestibular (inner ear) senses -- the infant responds to rocking and changes of position.

LANGUAGE DEVELOPMENT

Crying is a vitally important means of communication. By the third day of life, mothers can distinguish their baby's cry from others. By the first month of life, most parents can tell if their baby's cry means hunger, pain, or anger. Crying also elicits a nursing mother's milk letdown. The inherent biological response in most humans to crying insures the infant's survival.

The amount of crying in the first 3 months varies in a healthy infant between 1 to 3 hours a day. Infants who cry more than 3 hours a day are often described as having colic.

Colic in infants is rarely due to a physiologic problem. It may also be associated with overanxious mothers.

Excessive crying can be associated with child abuse. Regardless of the cause, it is a complex problem that deserves a medical evaluation.

BEHAVIOR

The behavior of the newborn is characterized by six states of consciousness: quiet sleep, active sleep,drowsywaking, quiet alert, fussing, and active crying. The ability to move smoothly from one state to another is one of the most reliable signs of neurologic maturity and integrity. Heart rate, breathing, muscle tone, and body movements vary with each state.

Many physiologic functions are not stable in the first months after birth. This variability is normal and differs from infant to infant. Temperature control, skin color, stooling, yawning, gagging, hiccupping, and vomiting are easily affected by stress and stimulation.

Periodic breathing, in which breathing starts and stops again, is normal and is not a sign of SIDS (sudden infant death syndrome). Some infants will vomit after each feeding, but have nothing physically wrong withem. Theycontinue to gain weight and develop normally.

Other infants grunt and groan distressfully while stooling but produce soft, blood-free stools and growth and feeding remain good. This is due to immature abdominal muscles used for pushing, and does not require any intervention.

Sleep/wake cycles are extremely variable and do not stabilize until 3 months old. These cycles occur in random intervals of 30-50 minutes at birth and gradually increase as the infant matures. By 4 months old, most infants will have one 5-hour period of uninterrupted sleep.