Pregnancy and Nutrition
Pregnant women undergo several physiological changes resulting in a rise in the plasma volume and the number of red blood cells in the body. Body nutrients, plasma binding proteins, and important micronutrient levels significantly decrease. The physiological changes, mostly caused by under nutrition and poor medical care in most developing countries causing under nutritional anomalies, such as anemia, 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 their low concentration in their body. Most of these micronutrients administered have limited benefits with the exemption of folic acid given during the periconceptional period. Pregnant women living in third-world countries may benefit from the many micronutrient prophylaxes, but the underlying 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 their nutritional needs and the nutritional needs of the fetus, it is important for them not to be deprived of any nutrients they require.
Pregnancy comes with an increase in demand for both nutrients and energy to cater for both the mother and the growing fetus. The body needs only a small additional amount of energy because the women’s body adapts to the rise of energy requirements; hence, there is a reduction in metabolic rate and a reduction in physical activity according to the American Journal of Public Health. Average well-nourished women require 10460 kJ/d at their last semester of 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 deliver. However, small infants are at a high risk of medical complications. Smaller infants, deprived of nutrients during the mother’s pregnancy, adapt to the limited supply of nutrients. As a result, their body’s metabolism and physiology change permanently.
The body’s micronutrient requirements increase significantly during pregnancy. Losses and malabsorptions caused by gastrointestinal tract diseases, inadequate dietary intake, ignorance about dietary requirements, and dietary taboos often cause deficiency of nutrients in the bodies of pregnant women. Conditions such as anemia and hypertension induced by pregnancy commonly cause both infant and mother deaths in third world countries. Maine, however, suggests that there is little to no evidence that nutrition is the cause of hypertension during pregnancy.
Vitamins and minerals as micronutrients greatly reduce the cases of infant and mother mortality. They directly treat illnesses caused by pregnancies or lower the cases of complications that may arise during pregnancies. The effectiveness of iron and foliate supplements focuses more on infant outcomes, preterm delivery, prenatal mortality, and deliveries with low birth weights. Speaking of infant outcomes, we need to make a clear distinction between the teratogenic causes of deficiency at preconception and the later stages in pregnancy. Deficiencies of foliate in diet during the preconception stage cause neural tube defects. Iodine deficiencies at this stage also cause cretinism. Both iodine and foliate deficiency at the later stage in pregnancy cause 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 intake rather essential.
There is scanty data on the mineral metabolism and amount of mineral requirements and their relation to each other during pregnancy. This makes it hard to determine the consequences of deficit or excess amount of minerals the body receives during pregnancy. The mother’s metabolism greatly altered by hormones that cause pumping of nutrients through the placenta and the mother’s breasts, as well as nutrient transfer to the growing infant in the womb, causes 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 no pregnant state, caused by a 45-50% plasma volume expansion and 15-20% red blood cell mass expansion.
Calculating of the nutrient requirements of pregnant women involves adding an increment to non-pregnant women requirements to cover for the costs of the growing fetus and the changes in the metabolism in the mother’s bodies. This approach, however, does not put into consideration the changes in metabolism, absorption, and excretion compensating 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, minerals, and trace elements, biochemical indexes (for example, hemoglobin) also fall in parallel to the volume of the red blood cells in the body, according to the American Journal of Public Health. Concentrations of zinc reduce significantly in pregnancy states, whereas the body’s level of magnesium in pregnancy depends on gestation until later on in pregnancy, where it later declines at a steady pace, 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 during pregnancy. Earlier in pregnancy, the level of calcium absorption increases significantly. The fraction of protein bound in serum declines significantly throughout pregnancy, whereas the level of concentrations of free ions appears to remain at a constant level. Homeostatic ionic calcium control is maintained at a steady level by vitamin D, calcitonin, and parathyroid hormone interactions.
Dietary requirements involving the intake of micronutrients recommended for pregnant mums 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 versus the non-pregnancy states are 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 average. Bothwell describes the iron requirements during pregnancy states. According to the Organization of Food and Agriculture, the recommended diet is based on bioavailability and is estimated to be at 187% and 407% for pregnancy states. Thus, 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 in pregnancy states.
Although calcium deficiency appears not to manifest itself in pregnancy states, it clearly 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’s 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 reduced bioavailability of iron causes severe anemia and has high chances of 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 appear to offer little supporting data. High amounts of copper and iron in diet appear 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 thymic cell, release of thymic hormone, and 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 brought about by the deficit of selenium in soil. There is, however, little or no evidence of deficiency in copper causing any pathological effects in the mother or the fetus.
Deficits 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 2500 mg/d. There is also evidence that in low-calcium populations, dietary supplements have a high chance of reducing hypertensive disorders and chances of preeclampsia during pregnancy, according to Belizan professional communication in the year 1999. This will also 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, supplement of phosphorus in diet is not recommended Phosphorus UL in pregnancy states reached and agreed at 3.5 g/d solves the issue. Magnesium supplements in pregnancy have no much worth according to the unpublished observations of MJ Keirse in 2000. The magnesium’s UL during pregnancy is relatively the same as that of other adults and stands at 350 mg/d. In the third semester of pregnancy, prophylactic iron in diet supplementation recommended not only for iron deficient anemic women but also for pregnant women with low iron stores appears to work.
Zinc has little data concerning its recommended intake in dietary supplements. The IOM, however, recommends zinc supplements when supplemented iron levels are greater or equal to 30 mg/d to avoid interactional effects of 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 have children with low birth weights and those having 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 all have reported preliminary conclusive data from the current study, where women were given a dose of 20 mg of zinc sulphate daily to solve the problem.
For about 680 women, whose data are available, zinc concentration appears to have had no effect on the potassium levels measured in the body. In regions with relatively low iodine levels, women should add the iodized salts in their food before and even after pregnancy. This in turn greatly reduces the chances of reproductive loss and adverse outcomes in fetal births. According to the World Health Organization, the recommended dietary intake of iodine is set at between 100 ?g/d to ?g/d. Supplementation of selenium in diet is highly recommended in areas where there is a common occurrence of Keshan disease. Safe levels of supplementation of selenium in diet for pregnant women have not yet been set, but that figure for other adults stands at about 400 ?g/d. Since there is no observable copper deficiency, its supplementation in 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 solve the problem. The IOM recommends copper supplements in the doze of 2 mg given to counteract copper zinc interactions, 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 adverse effects in case of deficiencies.
Just as minerals, lipid soluble vitamins are also essential during pregnancies. Blood levels of vitamin A are reported to decline gradually due to hemodillution. Inadequate dietary supplementations of vitamin A cause its low blood concentrations. The active for 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 are hence used.
Deficiencies in vitamin A arise from the limited dietary intake for 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 numbersare also associated with the deficiency in vitamin A. Deficiencies in vitamin D 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 sunrays. Vitamin K deficiencies, like vitamin D deficiencies, are just as rare. The antagonist effect of anticoagulant on vitamin K also puts women taking oral anticoagulants at a higher risk of hemorrhage.
Supplementations of soluble vitamins in diet for pregnant women therefore appear to be a necessity. Vitamin A supplementation of 7000 ?g in Nepal appears to reduce maternal mortality by 40% and a reduction of night blindness disease by 38%. Since the deficiency of vitamin A brings about anemia, supplementing pregnant women’s diet with vitamin A plus iron at the third semester curbs cases 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 is recommended. Most diets contain animal and plant oils to 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 to pregnant women. Serum levels of vitamin C decrease progressively in pregnancy. This probably happens with the extra uptake of the vitamin 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 make 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 additional 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 approach 10%. Evidence shows intake of vitamin C by women living in developing countries is low and inadequate. According to Sharma et al (92), Clemetson, and Cafaro (93) report, 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 their 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. The deficiency of vitamin B6 also causes low immunity by reducing white blood cell numbers and causing graft rejection. Foliate deficiency is reported in parts of India and Burma due to inadequate dietary intake and poor cooking habits. Deficiencies of vitamin B12 in pregnant women are rare. In cases where it occurs, manifestations include megaloblastic anemia. Supplementation of ascorbic acid in a diet for pregnant women is recommended for levels below 1 g/d. Hematological response to iron necessitates 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 B6 is a hundred mg/d. Neural tube defects reduce greatly by 75% when administering folic acid in a 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 rarely posing a great danger to pregnant women. Apart from the availability of balanced diets, cultural beliefs and taboos play a role in the deprivation of women living in developing countries of the dietary requirements they need during pregnancy. 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 the chances of infant and mother mortality. Mothers living in developing nations can reach cheaper nutritional solutions.