NUTRITIONAL NEEDS DURING PREGNANCY
Some specific nutrient requirements are increased dramatically during preg-nancy, as can be seen in Table 11-2. These figures are recommended for the general U.S. population; the physician may suggest alternative figures based on the client’s nutritional status, age, and activities.
The protein requirement is increased by 20% for the pregnant woman over 25 and by 25% for the pregnant adolescent. Proteins are essential for tissue building, and protein-rich foods are excellent sources of many other essential nutrients, especially iron, copper, zinc, and the B vitamins.
Current research indicates there is no need for increased vitamin A dur-ing pregnancy. Excess vitamin A (more than 3,000 RE) has been known to cause birth defects such as hydrocephaly (enlargement of the fluid-filled spaces of the brain), microcephaly (small head), mental retardation, ear and eye abnormalities, cleft lip and palate, and heart defects. The required amount of vitamin D is 10μg. The requirement for vitamin E is 15 mg -TE. The amount of vitamin K required is given as AI of 75 to 90μg depending upon age.
The requirements for all the water-soluble vitamins are increased during pregnancy. Additional vitamin C is needed to develop collagen and to increase the absorption of iron. The B vitamins are needed in greater amounts because of their roles in metabolism and the development of red blood cells.
The requirements for the minerals calcium, iron, zinc, iodine, and sele-nium are all increased during pregnancy. Calcium is, of course, essential for the development of the infant’s bones and teeth as well as for blood clotting and muscle action. If the mother is not consuming adequate calcium in her diet, the baby will get its calcium from her bones.
The need for iron increases because of the increased blood volume during pregnancy. In addition, the fetus increases its hemoglobin level to 20 to 22 grams per 100 ml of blood. This is nearly twice the normal human hemo-globin level of 13 to 14 mg per 100 ml of blood.
The infant’s hemoglobin level is reduced to normal shortly after birth as the extra hemoglobin breaks down. The resulting iron is stored in the liver and is available when needed during the infant’s first few months of life, when the diet is essentially breast milk or formula. Therefore, an iron supplement is commonly prescribed during pregnancy. However, if the pregnant woman’s hemoglobin remains at an acceptable level without a supplement, the physi-cian will not prescribe one.