OUR NEEDS

Food for Expectant and Nursing Mothers

ICIE G. MACY AND HARRIET J. KELLY.

THERE is some truth in the saying that the expectant and nursing mother must eat for two, because the processes of reproduction involve growth and adaptation of the mother and her child and usually some degree of nutritional reconditioning of both of them.

During pregnancy and lactation as during growth and recovery from injury or disease or malnutrition the body's daily requirements of many food substances are increased, and they have to be added to the usual needs, which are based on varying conditions of activity, environment, and the nutritive plane she previously maintained.

Because the maintenance of a healthy chemical body structure depends on the presence in the food of many nutrients, the diets of expectant and nursing mothers must take into account the kinds and amounts of protein and the deficiencies or excesses of calories, minerals, and vitamins.

Thus the maternal and fetal needs may be fulfilled and their bodies fortified with reserves to withstand the hazards during gestation, labor, puerperium, lactation, and early infancy. Nutritional needs differ for different people.

A diet that meets the needs at one time may be insufficient under different physiologic conditions. One may retain large amounts of varied nutrients if the body is undergoing growth, pregnancy, or lactation or if it is underfed or undernourished, so that it requires nutritive conditioning or repletion. If the body has matured and is nourished satisfactorily, however, the amounts stored will be much less and in different proportions.

Lately we have been paying more and more attention to the perinatal concept of tying together the care of the mother and baby. The perinatal period includes the time before conception, all of pregnancy, labor, and the period immediately after birth.

A close relationship exists between the nutritional status of the expectant mother at the time of conception and the outcome of pregnancy, lactation, and the survival and health of the baby. Diets containing enough essential nutriments to satisfy the changing maternal needs therefore contribute to improved maternal health, reduced trauma and loss of maternal tissues during and after birth, greater nutritional stability of the infant, less chance of premature birth, and less illness of mother and child.

Experiences in prenatal clinics in this and other countries indicate that many women do not receive enough of the essential nutrients to satisfy their usual body needs; meet the augmented needs of reproduction; acquire enhanced reserves essential to meet sudden and unexpected periods of physiologic and pathologic stress that arise from ineffective fulfillment of biologic demands; and meet new needs of growth and development of the fetus and placenta. The placenta is the organ on the wall of the uterus to which the embryo is attached by means of the umbilical cord and through which it receives its nourishment. At term the placenta is the afterbirth.

Data from many studies confirm the effect of an adequate diet on the outcome of pregnancy when it is adopted early in the reproductive cycle. Furthermore, research demonstrates that women who conceive when their bodies are in an undernourished or malnourished state may not seek medical guidance until after the first 3 months. By then the biologic pattern of maternal growth and the development of the placenta and the organ and tissue structure of the fetus are established, and metabolic adaptations and stress abound and may leave a detrimental imprint on the lives and health of both mother and child.

The establishment of pregnancy and lactation depends initially in large measure on hormonal stimulation, but the nutritional status of the mother's body determines the success and efficiency with which her physiologic, metabolic, and functional needs are met. Nutrients, hormones, and enzymes are interrelated in metabolism, growth, and development.

Pregnancy introduces complex problems because the fetal organism is living in physiologic and metabolic union with the mother's body and depends on her for the performance of its digestive, excretory, and functional processes.

The mother also needs more food to secrete milk. Breast milk, a unique food, meets the requirements of the infant's delicate digestive system. Thus the adequacy of the mother's diet determines her ability to supply enough predigested nutrients to the fetus through the placental blood supply and to produce breast milk of adequate quantity and concentration to meet the infant's physiologic requirements.

Nutritional status involves the metabolic and physiologic condition of the individual who consumes the food. For instance, the full-term newborn infant who is nutritionally 9 months old at birth also has a characteristic biologic age with physiologic, functional, and nutritive requirements that determine its food response and resultant nutritional state.

PREGNANCY has three morphologic phases.

The first, the preimplantation period, extends approximately 2 weeks after conception.

Next is the interval of about 2 to 8 weeks, during which major construction of organs and tissue takes place. It is the biologic time and stage in the growth and development of the fetal organism when its nervous and excretory systems and sensory organs are most susceptible to untoward environmental conditions and when the possibility of abortion is greatest.

The third phase, from 8 weeks to term, is the period of most rapid fetal growth and development and most intensive maternal physiologic growth, nutritional reconditioning, and preparation of reserves for meeting the extra demands of approaching labor, puerperium, and milk production.

Each phase of pregnancy exerts its own characteristic physiologic, functional, and nutritive demands as a result of the many functional and regulatory mechanisms that are initiated by the products of conception.

Each phase of the life cycle has its own nutritive requirements and its own physiologic disturbances and diseases.

The endometrium, the membrane lining the uterus, is prepared for the ovum during the preconceptional periods and early pregnancy.

The implantation of the fertilized ovum, however, brings into play many new hormonal changes. They result in an unbalanced physiologic state, with which are associated disturbances of the gastrointestinal system, such as depressed appetite, reduced food consumption and utilization, nausea, and possibly loss of weight.

Metabolic changes as the result of conception may be observed in the level or distribution of blood components; the level -or distribution of urinary components; the retention or loss of nutrients; and the composition and developmental changes of the fetus, the placenta, and the adnexa (other fluids and structures associated with maintenance of the fetus).

THE PRIMARY function of the placenta is to store and transport nourishment from mother to embryo and provide a mechanism for returning the end products of the embryo's metabolism to the mother's blood stream. It is a storehouse for the building and maintenance materials from which the fetus, in a highly selective way, may draw its nutrients for growth and development.

Indeed, the complex mechanism for the nutrition of the human embryo, from the time that the fertilized ovum is embedded in the uterus to maturation and birth, must function through the specialized placental structure.

Normally the chemical composition of the placenta during gestation varies to suit the demands made on it by the growing fetus. The fat and carbohydrate contents, for example, are reduced in the last quarter of pregnancy; the vitamin content of the placenta may increase during the pregnancy and change near its end.

The fetal part of the placenta at term has developed to the extent that it forms the major part of the organ.

We have indications that all the morphologic and metabolic changes that occur in the human body during a person's lifetime take place in the placenta during the short span of gestation.

Changes occur in the thyroid and pituitary glands and in the distribution of the ovarian and placental hormones during gestation.