Reflexes in the Newborn

Primitive automatic movements, called reflexes, are present in an active fetus for many months before delivery, as if in preparation for the coming event. The patterns of these reflexes are often remnants from our heritage, our monkey and amphibian ancestors, but they may also serve a purpose. The fetal activity appears to keep the uterus contracting (Milani Camparetti, 1981)¹. When dystoda (the slowing down of the uterine contractions) occurs, an inactive fetus may be a contributing factor. Until fairly recently, obstetricians have usually laid the cause of dystocia to an inefficient uterus, but there is more and more reason to suspect an interaction between an inactive fetus without reflex movement patterns and an understimulated, underreactive uterus. Reflexive behaviors also seem to play a role in the writhing necessary to help the fetus work through the cervical opening. Among these reflexes are:

1. Tonic neck reflex. With head turned abruptly, the fetus assumes a fencing-like position, arching the body, extending or stretching out all muscles on the face side of the body, and flexing on the other side. As labor progresses, the head turns to make the body arch one way, then the other, so that the baby swims its way along through the cervical canal.
2. Spinal cord reflex. If the back is stroked along the spinal cord, the entire body curls up toward the stroke. The trunk will switch back and forth in reptilian movements if there is enough stimulation along the spinal cord. In labor, the touch of the birth canal wall keeps the baby arching back and forth, inching forward (Galant, in Saint-Anne D'Ar-gassies, 1974)².
3. More or startle reflex. As the head is extended backward, the arms extend outward, then flex, and the legs are thrust outward. These movements are suppressed in the cervical canal but would free the baby from a "stuck" situation if his or her head became arched suddenly.
4. The step reflex and the standing reflex. These emerge as the baby's feet press on a stable surface and are good examples of the stretching extensor reflexes of all muscle groups. As labor proceeds, the alternating flexion and extension of extremities is likely to play a major role in stimulating the uterus.
5. Crawl reflexes. When newborn babies are placed on their bellies, they automatically try to pick up and turn their heads to free the airway. Their arms come up beside the head and they attempt to get their hands into their mouths. Their legs push back and forth in vigorous crawling movements. These are precursors of crawling later on. Parents can see that the baby is already programmed to move forward in bed, and also that the baby will raise his or her head to free it from bedclothes, when lying face down.

Reflex motions are programmed at a very primitive level in the brain. Apart from being adaptive in labor and delivery, they may play a role in programming motor behavior in a way that makes it predictable to parents. For example, in the tonic neck reflex, each side of the baby's body behaves differently. One side will respond with flexion, the other with extension movements. The Moro causes a baby to reach out, then grasp onto the mother's body. Parents may be unaware of this patterned behavior at first but will rapidly learn to depend on it as they play with their baby. Of course, all of these reflexes become a base for learned, complex behavior later on. The step or standing reflex sets the stage for future learned behavior of walking and standing. When parents or the pediatrician or nurse hold newborns to a standing position, their faces will often brighten and they appear to be attempting to participate. This, in turn, delights and rewards the adult, setting up feedback for future learning.

Swaddling is used in many cultures to replace the constraints offered by the uterus and then by a mother's holding and containment. Such control over disturbing motor responses allows newborns to attend to and interact with their environment. The Navaho Indians used cradle-boards and swaddling. Observers noticed that their babies quieted as soon as they were wrapped onto the cradleboard. Clyde Kluckhohn (1948)³ felt that this custom led to quiet, passive, but internally frustrated infants. When we [TBB] have worked with Navaho babies, we have seen the quieting, but not the frustration. Mothers handled the swaddled babies easily, propping them up to watch as they worked in the fields, laying them down to sleep wrapped on their cradleboard. Essentially, Navaho babies became observers and thus participants in the lives of the adults around them because of the cradleboard. The present use of baby chairs seems comparable in certain ways.

1. Sucking and gagging reflexes. Initially, newborn babies need to rid themselves of the mucus in their airways. At this point, gagging reflexes compete with sucking. As a result, a baby's response to a nipple or finger will often be to gag and spit up before he or she can begin to suck. An eager new parent who puts her baby to breast will feel rejected if she finds the baby gagging or refusing to suck. The sucking reflex must be gradually brought out and reinforced-often it takes several days.

   This gradually improving sucking reflex parallels the mother's milk production. A new mother doesn't get milk for four or five days. Meanwhile, her breasts produce a milky, whitish fluid full of protein and antibodies, but in small amounts. The first few days at the breast can be seen as a "learning" or practicing period. Adjusting to each other is the big job. Learning to suck is the baby's task. Learning how to hold and encourage the baby, to feel comfortable in nursing, is the mother's. This early practicing period takes the first week with a first baby. If hospital personnel or family try to rush this process, thinking that a new mother should know instinctively how to nurse a baby, they are likely to endanger her confidence in her ability to nurture her baby.

Feeding Behavior
Rooting and sucking are among the most reliable activities of newborn babies. When a breast is offered and touches a newborn's cheek, the infant will search for it by a few head turns, then almost gobble to mouth the nipple. An awake, hungry newborn exhibits active searching movements in response to any stimulation in the region around the mouth. This reflex is set off by touch as far out on the face as the cheek and sides of the jaw and head. The rooting reflex is present in a premature infant even before sucking itself is effective.

Sucking is made possible by the thorax when the infant breathes in and by fixing the jaw between breaths. Swallowing and breathing must be coordinated, and the depth and rate of breathing are handled differently when the baby is engaged in nutritive and non-nutritive (such as on fingers or a pacifier) sucking. In the latter, the chance of inhaling milk is not important. This whole process has been studied by Albrecht Peiper who argues for a hierarchical control system in which swallowing controls sucking and sucking controls breathing (Peiper, 1963)⁴.

There appear to be three components of sucking: a lapping motion of the tongue, a milking movement at the back base of the tongue, and suction from the upper esophagus. One can feel all three of these by putting a finger in the new baby's mouth. There is a brief delay before these become coordinated in an effective milking mechanism.

The infant sucks in a more or less regular pattern of bursts and pauses. During non-nutritive sucking, this rate averages about two sucks a second. Bursts seem to be arranged in groupings of 5-24 sucks per burst. The pause between bursts has been looked upon as a rest and recovery period as well as a time during which information is being processed by the neonate. These pauses, as we have mentioned, are important in the early mother-child relationship, since they are used by mothers as signals to stimulate the infant to return to sucking. Mothers tend to look down at, to talk to, and to jiggle babies when they pause between bursts of sucking. The infants, in turn, come to expect these responses. The mothers' jiggling actually prolongs the pause as the infants attend to the signals from their mothers (Kaye & Brazelton, 1971)⁵.

¹Milani Comparetti, A. "The neurophysiologic and clinical implications of studies on fetal motor behavior." Seminars in Perinatology 5(1981).

²Saint-Anne D'Argassies, C. Le Developpement Neurologique du Nouveau-Ne a Terme et Premature. Paris: Masson et Cie, 1974.

³Kluckhohn, C., and H. Murray. Personality in Nature, Culture and Society. New York: Knopf, 1948.

⁴Peiper, A. Cerebral Function in Infancy and Childhood. New York: Consultant's Bureau, 1963.

⁵Kaye, K., and T. B. Brazelton. "The ethological significance of the burst-pause pattern in infant sucking." Paper presented at meeting of Society for Research in Child Development. Minneapolis, MN, April, 1971.

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