Infants and Toddlers

GENEVIEVE STEARNS.

THE newborn infant differs from the adult as greatly in his inner makeup as in his outer dimensions. At birth he not only is small; his body proportions are different. His head is relatively large. His arms and legs are short and at first are almost useless. His body contains more water, and a much greater proportion of its water is outside the cells. Only one-fourth of his total weight consists of muscle, instead of nearly half of it, as in the adult. His skeleton, like the adult's, is about one-fifth of his body weight, but there the resemblance ends, for the newborn baby's skeleton has much more cartilage or gristle and is more than half water.

Only the central sections of the long bones are mineralized in the newborn. As an X-ray film shows only the mineralized portions, a film of a young baby's skeleton looks like a collection of separate bones. All these bones must be mineralized, and the baby has to increase his protein content,on a per Pound basis, at least to half again its birth proportion.

Each organ grows at its own rate growing is a much more complicated process than just getting bigger.

The full-term newborn baby has the ability to digest and absorb proteins, simple carbohydrates, and a moderate amount of fats.

Ordinarily he does not manage starches well, although infants who are given feedings thickened with starch for therapeutic reasons will begin to make amylase (a starch-digesting enzyme) in response to the stimulus.

His kidneys are functioning and can carry off wastes, although he needs more water, relative to his size, than the adult does to manage this excretion. His food needs to be simple and liquid. He can suckle, as can all young mammals, but is not ready to chew or swallow solid or semisolid foods. His alimentary canal can excrete unused food and gastrointestinal juices, after much of their water content has been absorbed.

His nervous system is not entirely complete and functioning. His eyes do not focus. His senses of taste and smell are not acute.

The blood of a newborn infant has a larger number of red cells and a larger amount of hemoglobin, the iron-containing red coloring of the cells, than at any other time in life. Before birth, the baby got his oxygen supply from his mother's blood and he returned the waste carbon dioxide to it. When he breathes air, with its far higher amount of oxygen, he does not need so much hemoglobin, and his body starts almost immediately to break down the excess. The iron in hemoglobin is saved and stored for future use, for his mother's milk contains very little iron.

The baby born at term of a well-nourished mother is usually in excellent nutrition at birth, sturdy, vigorous, and contented. The baby whose mother was in poor nutritional condition during her pregnancy is more apt to be born prematurely and require special care for survival. Even though born at term, he often is smaller, less vigorous, more apt to suckle poorly, and fretful.

An infant who has been born after fewer than 270 days in the womb or who weighs less than 5.5 pounds is considered premature. If the difference in time is small, such a baby can often catch up with the full-term infant. Often the premature infant is in a poor nutritional state. The greater the degree of prematurity, the more difficult are the problems just of keeping the baby alive and growing.

THE BABY BORN 2 months prematurely is a fragile and an unfinished product, weighing only about half as much as the full-term newborn. His body has much more water and much less protein and mineral per pound of body weight than the full-term baby. He has little fat and looks like a wizened ancient. His bones are so poorly calcified that the skull bones can be pressed inward easily. During the birth process, this molding of the skull permits increased pressure on the brain; hemorrhage with brain damage therefore is commoner among the prematurely born than among full-term infants.

Because the development of his nervous system is incomplete, the control of such vital functions as breathing, suckling, coughing, and heart rate are defective. Temperature regulation is poor because of his relatively large surface area and the incomplete development of the sweat glands.

His digestive ability and kidney function are more nearly effective, but much more water must be provided for each unit weight of feeding to enable him to excrete all his wastes. The nutrients which he should have received constantly from his mother's blood in a form that was ready for immediate use by his tissues must now be ingested at intervals, digested, and absorbed. Yet this tiny unfinished product, prematurely thrust into the world, is expected to grow more rapidly than he ever will again.

The causes of prematurity are many, but recent studies have shown that the incidence and degree of prematurity increase as the mother's nutrition worsens.

The death rate of prematurely born infants that were studied by scientists in Iowa was highest among those whose mothers had the poorest diets. The poorly fed young mothers were apt to deliver their first or second infants prematurely. Older mothers, whose food habits were considered fair to good but who had given birth to a series of infants in rapid succession, often could not carry their later infants to term. Their nutritional stores had become exhausted by multiple pregnancies. Such women need an excellent diet at all times.

The child needs to be well nourished during his 9 months of intrauterine life.

It is possible, even probable, that he will not be so unless special precautions are taken to improve the mother's nutrition. Nutritional deficiencies of mothers in much of the United States are due more to social factors, such as lack of education and resourcefulness, than to economic factors.

If every mother- and father-to-be realized how much safer the baby is from birth injury and how much easier he is to care for throughout infancy if he is kept well-nourished before birth, every precaution to provide sufficient nutriment for the mother and the baby would be taken.

Human milk of good quality and sufficient quantity is the normal food of the full-term infant. He is more likely to thrive smoothly on human milk than any other food. Maintenance of the mother in good nutrition is essential both for the production of a healthy baby and for the establishment of a good flow of milk of good quality.

The standard by which the rate of growth and development of any baby is measured is the average rate of growth and physical development of infants who are born at term of well-nourished mothers and who receive ample breast milk and, in addition, moderate amounts of vitamin D and vitamin C. Normal infants so fed grow well and usually remain healthy and sturdy. A formula-fed baby whose growth and development are significantly slower than those of the standard breast-fed babies is not thriving nutritionally.

Human milk fed directly from the breast of a healthy mother is always fresh and free from disease-producing organisms.

Because mother's milk customarily is not measured in amount or analyzed for quality, we tend to assume both factors are adequate. When the mother is poorly nourished, however, the amount of milk she secretes is small, and duration of lactation is short. Even under those conditions, if the amount of milk secreted permits some growth, the baby may fare better when breast fed if no other safe, properly prepared milk is available. His nutrition, however, is at his mother's expense; the ability to produce milk solely from her own body constituents is limited. If the mother is severely undernourished, her baby will not thrive if breast fed only.

Other factors than malnutrition or starvation also affect a mother's ability to produce enough milk of good quality to nourish her infant adequately. Most mothers in good health, however, if they have the support of their husbands and doctors, can produce enough milk for the needs of their babies.

During the first few days after the baby's birth, the milk secreted by the mother is quite different from that secreted later. This early milk is called colostrum; milk secreted later is called mature milk.

Colostrum is a thin fluid and contains more protein and salts and less sugar and fat than does later milk. The amount of colostrum is small, 1 to 2 ounces in the 24 hours. About the third to fourth day, the milk comes in, and the mother's breasts enlarge and become tender. By the end of 2 weeks, or soon thereafter, the change from colostrum to mature milk is complete.

The baby should get increasing amounts of milk daily and by 6 weeks to 2 months should be getting at least 2.5 ounces per pound to thrive.

Even though the baby can be breast fed only for a month or so, it is well worth while to nurse him. Colostrum and its gradual change to mature milk tide him over the difficult period of adjustment to the changed conditions of independent life. Nursing the baby through 6 months or more is still better. Continuation of nursing past 9 months is unusual in this country. Many physicians consider it unnecessary for the baby's health. Lactation beyond 9 months can be associated with a heavy loss of nutrients from the mother's body. Such length of lactation may be more harmful to the mother than helpful to the infant.

The young breast-fed infant should be given vitamin D in the amount of 300 to 400 I.U. (International Units) daily shortly after birth. It is customary in this country also to give the baby an added source of vitamin C beginning soon after birth, although if the mother has a good intake of vitamin C, her baby will have enough.

Often preparations containing vitamins A, C, and D are prescribed for infants. Additional vitamin A is not needed by the breast-fed infant whose mother is well fed. In countries in which vitamin A deficiency is common, its addition would be wise. The practice of giving orange juice or other natural sources of vitamin C accustoms the baby to the bottle and nipple and to a different flavor at an early date. In case of emergency weaning, the baby accustomed to a nipple is not so disturbed over the process. The baby who is accustomed to two different flavors is not apt to be so reluctant in accepting new foods as the baby who has been given only milk.

Other supplementary foods for the breast-fed infant I discuss later.

HUMAN MILK AND COW'S MILK differ in many respects.

Human milk, though far and away the best first food for the healthy full-term baby, nevertheless is a food that provides little if any excess of any nutrient. It is a most successful food for the full-term infant when it is adequate in quantity. It is a safe food, for it goes directly from mother to baby without storage or contamination.