Pregnant women undergo several physiological changes resulting in the rise in the plasma volume and the number of red blood cells in the body. The level of body nutrients, plasma binding proteins and important micronutrients levels significantly reduces. The physiological changes make the need of having proper and adequate nutrition a necessity. Under nutrition and poor medical care in most developing countries results in anomalies such as anemia that eventually, cause medical problems to the mother and the developing fetus in the womb. Women in developed countries are often given several recommended micronutrients to supplement the low concentration of important micronutrients their body needs have successful pregnancies. Most of these micronutrients administered have limited benefits with the exemption of folic acid given during periconceptional period. Women living in third world countries may benefit from the many micronutrients prophylaxis when pregnant but the underlying basis to change from supplementation with foliate and iron to micronutrients is still debatable according to the American Journal of Dietetic Association. Since pregnant women cater for both their nutritional needs and the nutritional needs of the fetus, it is important for them not deprived of any nutrients they require.
During pregnancy, the body needs only a small additional amount of energy because the women's body adapts to rise of energy requirements and hence there is a reduction in both the metabolic rate and physical activity according to the American journal of Public Health. Average well-nourished women require ≈10460 kJ/d at their last semester of the pregnancy. Many women living in third world countries, however, restrict their dietary intake to bear smaller babies on the perception that smaller babies are easier to bear. However, small infants are at a higher risk of attaining medical complications. Smaller infants deprived of nutrients in pregnancy adapt to the limited supply of nutrients their bodies are used to hence their body's metabolism and physiology changes permanently.
The body's micronutrient requirements increase significantly during pregnancy. Losses, malabsorption caused by gastrointestinal tract diseases, inadequate dietary intake, dietary taboos and ignorance about dietary requirements during pregnancy are often the major causes of deficiency of nutrients in the bodies of pregnant women. Conditions such as anemia accompanying pregnancy and hypertension induced by pregnancy commonly cause both infant and mother deaths in third world countries. Maine, however, suggests that little or no evidence of nutrition being the cause of hypertension caused by pregnancy.
As components in diets of pregnant women, vitamins and minerals as micronutrients greatly reduce the cases of infant and mother mortality. This is by directly by treating illnesses caused by pregnancies or on the other hand lowering the cases of complications that may arise during pregnancies. The effectiveness of supplementing the diet with iron and foliate tends to focus more on infant outcomes, preterm delivery, prenatal mortality and deliveries with low birth weights. Considering the focus on infant outcomes, we need to make a clear distinction between the teratogenic causes of deficiency at preconception and at a later stage in pregnancy. Deficiencies of foliate in diet during preconception stage in pregnancy cause neural tube defects. Iodine deficiencies at this stage will cause cretinism. However, both iodine and foliate deficiency in a later stage in pregnancy causes retardations in growth and delivery complications. The two distinctions are important considering the fact that many women living in developing countries have unplanned pregnancies and deliveries hence making iron and foliate a requirement to be substituted in the diet almost throughout the period of pregnancy.
There is scanty data on not only the body's mineral metabolism and amount of mineral requirements but also their relation to each other during pregnancies. This makes it hard to determine the consequences of the deficient or excess amount the body receives during pregnancy. The mother's metabolism changes as soon as hormones that cause pumping of nutrients through the placenta to the growing infant in the womb start causing the deficiency. The kidney also increases its function to cater for the excretion of metabolic wastes of both the infant and the mother causing an increase in the excretion of urine soluble vitamins such as foliate in the mother's urine. By the third semester, the blood volume and composition changes greatly. There is an increase in the blood volume by 35-40% above the non-pregnant state caused by a 45-50% plasma volume expansion and 15-20% red blood cell mass expansion.
Calculating the nutrient requirements of pregnant women involves adding the increment above the requirements of non-pregnant women that cover the costs of the growing fetus. This approach, however, does not put into consideration the changes in metabolism, absorption and excretion that compensate for the increase in nutrient requirements in case there is no or less dietary intake.
Since the addition of erythrocytes mass is less than the increase in plasma increase, minerals and trace elements biochemical indexes for example hemoglobin also fall in parallel to the volume of the red blood cells in the body. This is according to the American Journal of Public Health. Concentrations of zinc reduces significantly in pregnancy states were as the body's level of magnesium in pregnancy depends on gestation n until later on in pregnancy were it declines at a steady state. This is according to the unpublished observations of MJ Keirse in 2000. Maternal adaptations cause phosphorus levels in the maternal body to remain relatively constant. On the other hand, the level of copper in the body seems to increase in pregnancy. During the earlier stages of pregnancy, the level of calcium absorption increases significantly. The fraction of protein bound in serum declines steadily throughout pregnancy whereas the level of the concentrations of free ions appears to remain at a constant level. Homeostatic ionic calcium control maintained at a steady state by vitamin D, calcitonin and parathyroid hormone interactions works.
Dietary requirements involving the intake of micronutrients recommended for pregnant mothers in their last semester by the National Research Council and the United Nations Food and Agriculture organization together with the World Health Organization have been established and recommended. The calcium RDA increases by 122-167% in pregnancy states over the non-pregnancy states caused by the requirement of calcium for the use by the fetus during skeletal development. There is, however, no evidence for a rise in RDA requirement for magnesium and phosphorus above the levels in non-pregnant women's levels. Bothwell describes the iron requirements during pregnancy states in his online articles on pregnancy and nutrition. According to the Organization of Food and Agriculture, the recommended dietary increase basses on the bioavailability of nutrients in the body and is estimated to be at 187% and 407% for pregnancy states. At pregnancy states, the RDA of zinc rises to 44% and that of iodine to 33%. Selenium requirements also increase to 26% in order to cover for fetal demands. Copper appears to be relatively unchanged thought pregnancy.
Although calcium deficiency appears no to manifest in pregnancy states, the deficiency shows in cases hypothyroidism and dietary inadequacy during pregnancy states. Low levels of calcium and magnesium appear to cause hypertensive disorders in pregnancy according to MJ Keirse unpublished observations in 2000. Most foods people eat contain phosphorus hence making deficiencies in phosphorus levels in pregnancy states rare. A deficiency in iron caused by a reduced bioavailability of iron causes severe anemia and has a high chance of causing maternal mortality. Deficiency in iron also brings about a reduction in immunity hence making iron important in reducing chances of maternal infections. The deficiency of zinc in pregnant women and its effects appears to have little data presented. High amounts of copper and iron in the diet appears to compete with zinc for absorption in the gastrointestinal tract hence causing zinc deficiency. Low zinc levels have been associated with abortions, premature births, intrauterine retardations in growth and preeclampsia. Zinc deficiencies also cause a reduction in the development of the thymic cell, release of thymic hormone and a reduction in thymic cell functions hence greatly reducing the body's immunity. Iodine deficiency in dietary intake causes fetal loss and mental retardation while selenium deficiency, on the other hand, causes Keshan disease, common in women of reproduction age in China. The main cause of this is its deficiency in the soil. There is however little or no evidence of deficiency in copper causing any pathological effects on either the mother or the fetus.
Deficiencies in minerals during pregnancy have several teratogenic effects hence dietary supplementation is greatly necessary. According to McCaron's unpublished reports in 2000, calcium supplementation in diet during pregnancy states is safe. The tolerable intake is at 2500 mg/d. There is also evidence that in low calcium acquiring populations, dietary supplementations have a high chance of reducing hypertensive disorders brought up by pregnancy. Chances of preeclampsia according to J Belizan professional communication in the year 1999 are independent of the level of calcium in the body. Calcium intake, however, will significantly reduce the high risk of attaining postnatal depression. There are however, no cases of a change in bone mass or the level of blood concentrations of inorganic phosphorus hence supplementation of phosphorus in the diet is not necessary. Phosphorus UL in pregnancy states is 3.5 g/d. Magnesium supplementation in pregnancy has no worthy in any written documents according to the unpublished observations of MJ Keirse in the year 2000. The magnesium's UL during pregnancy is relatively the same as that of other adults and that is 350 mg/d. In the third semester of pregnancy, a recommendation for prophylactic iron supplementation in diet not only for iron deficient anemic women but also for pregnant women with low iron stores applies.
Zinc has little or no evidence of its requirement in dietary supplementation. The IOM, however, recommends zinc supplementations when supplemented iron levels are greater or equal to 30 mg/d to avoid interactional effects between the two. Zinc supplementations improve the outcomes of pregnancy as per JC King's unpublished observations in 2000. The United Nations W.H O. recommends prophylactic zinc doses amounting to 20-25 mg for women in many developing countries in the world. In the United States of America, women bearing babies with low birth weights associated with consuming a low dietary intake of zinc have recommended dietary supplementation of 25 mg Zn/d starting from the 19th week of gestation. These findings are associated with women having a body mass index of less than 26. Hakimi ET reported preliminary conclusive data from the current placebo controlled were women receive a dose amount of 20 mg of zinc sulphate daily to solve the problem. About 680 women, whose data is available, zinc concentrations appears not to have had any effect on the potassium levels measured in the body at normal body temperatures.
In regions having relatively low iodine levels women should take food cooked using iodized during, before and even after pregnancy. This in turn greatly reduces chances of both reproductive losses and adverse outcomes in fetal births. According to the World Health Organization, the recommended dietary intake of iodine is set at between 100 μg/d to μg/d. Supplementation of selenium in the diet is highly recommended in areas where there is a common occurrence of Keshan disease. Safe levels of supplementation of selenium in the diet for pregnant women have not yet been set but that of other normal adults is about four hundred μg/d. Since there is no observable copper deficiency, its supplementation in the diet is also not considered. However, zinc supplements administered to patients and pregnant women having low copper levels in their bodies solve the problem. Copper supplements given to counteract the effects of zinc-copper interactions appear to have good outcomes in pregnancy. The IOM recommends copper supplements given to counteract copper zinc interactions of 2 mg when there is an application of a supplementation of zinc. The recommended UL for copper at pregnant states are 10 mg/d. Several other minerals essential for pregnant women include molybdenum, chromium and manganese but there are no severe effects in case of deficiencies.
Just as minerals, lipid soluble vitamins are also essential during pregnancies. Blood levels of vitamin A reported to decline gradually caused by hemodillution. Inadequate dietary supplementations of vitamin A cause its low blood concentrations. The active form of vitamin D, i.e. 1-25 dihydrocholecalciferol rises in pregnancy state while on the other hand, its inactive form, and 25-hydrocholecalciferol reduces significantly. Gestation increases the blood levels of vitamin E probably caused by the state of hyperlipidemia that is associated with pregnancy. The United Nation W. H.O in association with Food and Agriculture Organization has put the RDA for vitamin A at 20% higher for women that are pregnant above non-pregnant women. This is because of its requirement in the cell division and the body development of the growing fetus. Exposing the skin to sunlight reduces the deficiency of vitamin D but it depends on the intensity of sunlight, the amount of the skin that is exposed and the duration of exposure. According to the United Nation's F. A.O, the need for vitamin D increases to 300% to meet the requirements of the fetus for vitamin D used in skeletal development. The difficulty in determining the requirements of vitamin E during pregnancies, however, makes it hard to determine the RDA for the vitamin. According to the NRC assumptions, vitamin E has an RDA of 25 % in pregnancy. There is insufficient data for the given RDA for K vitamin in pregnant women and the available recommendations for non-pregnant non-lactating women is hence used.
Deficiencies in vitamin A arise from the limited dietary intake of dairy products, vegetables rich in carotene and malabsorption. Deficiency in vitamin A in pregnancy is associated with night blindness and increases the chances of maternal mortality. Cases reported also indicate fetus retardation in growth, premature births, and low birth weights associated with vitamin A deficiency. A reduction in leukocyte count, weight in lymphoid tissues, a reduction in T cell functioning and natural killer numbers is also associated with a deficiency in vitamin A. Deficiencies in vitamin D, on the other hand, are rare but in case they occur, fetal rickets, abnormal development in teeth and neonatal tetany are the resultant effects. The deficiencies in vitamin D only occur in women with limited durational exposure to the rays of sunlight. Vitamin K deficiencies, just as vitamin D deficiencies are just as rare. The antagonist effect of anticoagulant on vitamin K also makes women taking oral anticoagulants at a higher risk of having hemorrhages.
Supplementations of soluble vitamins in the diet for pregnant women, therefore, appear to be a necessity. Vitamin A supplementation of 7000 μg in Nepal appears to reduce maternal mortality by 40% and a reduction of night blindness disease by 38%. Since deficiency of vitamin A is a cause for anemia, supplementing pregnant women's diet with vitamin A plus iron at the end of the third semester reduces chances of anemia. Vitamin D dietary supplementation is not such a necessity. Large doses of vitamin D are toxic not only to the mother but also the fetus hence administration of smaller amounts instead of large doses. Most diets contain animal and plant oils provide enough supply of vitamin D hence making its extra supplementation in diet, not a necessity. Both vitamin K and vitamin E are non-toxic to humans even at higher levels.
Water-soluble vitamins such as vitamin C are also important for pregnant women. Serum levels of vitamin C decreases progressively in pregnancy. This probably results in the extra uptake of the vitamins by the fetus. The serum levels of niacin decreases during pregnancy whereas its urinary excretion elevates. The increase in blood volume and an increase in the rate of active and passive transport through the placenta cause the level of vitamin B to reduce significantly. Decreased intestinal absorption, inadequate dietary intake or increased demand for foliate also makes foliate deficient in pregnant women. Biotin levels fall low in pregnant women lower than in non-pregnant women and continue decreasing progressively throughout pregnancy hence making it a necessity for its supplementation in the diet.
Vitamin C RDA for pregnant women requirement is 67% higher above than that of non-pregnant women. In early pregnancies, the dietary allowances for thiamine are 12% higher due to the increased body requirements. Synthesis of riboflavin by the fetus and maternal tissues increases in pregnancy making its dietary requirements is as low as 7%. The same reason makes the dietary requirements of niacin 10%. Evidence shows intake of vitamin C in women living in developing countries is low and inadequate. According to Sharma et al in 1992 and in Cafaro 1993 reports, there is an association between low concentrations of vitamin C and occurrences of abruption placenta in pregnant women. Deficiencies in thiamine are rare but occur in areas where the main staple meal is rice. The extra needs by the growing fetus create a deficiency in riboflavin. Its deficiency is associated with a decrease in immune response, low thymic weights and low numbers of circulating lymphocytes. Deficiency of vitamin B 6 also causes low immunity by reducing white blood cells numbers and causes graft rejection. Foliate deficiency reported in parts of India and Burma due to inadequate dietary intake and poor cooking habits. Deficiencies of vitamin B 12 in pregnant women are rare. In cases where it occurs, the manifestation is megaloblastic anemia. Supplementation of ascorbic acid in diet for pregnant women recommended for levels below 1 g/d. Hematological response to iron needs supplementation with riboflavin in the diet. There is less or no evidence of toxicity caused by riboflavin by oral administration. Niacin has a UL of 35 mg/d while that of vitamin B 6 is a hundred mg/d. Neural tube defects reduce greatly by 75% when administering folic acid in diet for pregnant women. In countries having high incidences of megaloblastic anemia, folic acid prophylactic medication becomes a necessity. There is, however, no evidence of supplementing folic acid in diet being unsafe except for women on anticonvulsant drugs.
In conclusion, many women living in developing countries only have access to diets containing cereals. Animal products, fruits and vegetables are rare therefore posing the great danger to pregnant women living in undeveloped countries. Apart from the availability of balanced diets, cultural believes and taboos play a role in the deprivation of women living in developing countries on the dietary requirements they need when pregnant. To determine the micronutrients pregnant women living in developing countries need, a consensus and a comprehensive approach needs to decide on what forms of micronutrients pregnant women need to reduce chances of infant and mother mortality. Mothers living in developing nations can reach cheaper nutritional solutions at that are affordable.