Postnatal Growth of Babies

Development of a baby from prenatal to postnatal stage is very gradual. Here, motor co-ordination, locomotion and language are involved.

The newborn infant has postural reflexes of the arms at the elbows and of the legs at the knees. A typical reaction of this sort is the 'startle response,' which results from the sudden loss of support. If the infant is held in the hands, face up, so that the arms and legs are free to move, any sudden drop will cause a quick outward extension of both the arms and legs. This response is present at birth, and there are indications that it lasts throughout life.

The development of infant behavior which results in the ability to maintain an upright posture begins at the head and proceeds down the neck and trunk to the legs. At birth the baby has no control over its head and neck muscles, but gradually these muscles come under control so that the attendant's hands need be placed only at the nape of the neck, later at the shoulder blades, still later near the middle of the back and finally only under the buttocks.

The varying degrees of support necessary to keep the baby sitting upright on the lap also explains the principle that the infant begins to assume an erect posture at the head end and gradually works downward. Behavior development parallels structural development from the head downward and from the general to the specific.

Although local reflex movements do not become highly specific until the child reaches several years of age, the growing infant shows an ever-progressing motor coordination as specific reflex movements develop. When we observe the sequences of growth leading the infant from a chin-up position to walking alone, we see the general to specific and the head to toe development. In the first month, the infant can hold up its chin for only brief periods of time. In the second month the chest can be raised.

At four months the infant can sit in upright position only with support and by five months, he sits on one's lap and grasps at an object. By seven months, the average child can sit alone, and a month later, he can stand with help. By nine months, the child can stand holding on to furniture; he can creep at ten months and walk when led at eleven months. By one year of age, the child can pull himself up by holding on to furniture; a month later, he can climb stairs awkwardly. The child can stand alone at fourteen months of age and at fifteen month can walk around by himself. Of course, some children go through these sequences at an earlier age and some at later ages.

As the vocal organs continue to develop, the sounds become more definite. "Mama" and "Da-da" are at first meaningless vocalizations to the baby. As the mother repeats, "Mamma" to the child, he gradually learns to associate the sound with mother. This step marks the beginning of a meaningful language.