Summary

Nutrient needs during pregnancy are increased in order to support the growth of the fetus while maintaining the mother’s health. This increased need is met by a combination of physiological adaptations by the mother’s body and increased nutrient intake from food and dietary supplements.

For some micronutrients, such as folate, iron, iodine, and zinc, the requirement is substantially increased. For other micronutrients, the requirement is slightly increased (magnesium, vitamin C) or unchanged (calcium, vitamin D, vitamin E), yet it remains important to meet the recommended levels of intake for a healthy pregnancy. In the United States, several of these micronutrients are considered shortfall nutrients, meaning that they are under consumed by eating a typical American diet. In the developing world, iron, folate, vitamin A, and iodine are in scant supply and their deficiency during pregnancy can contribute to multiple adverse outcomes in the mother and newborn. Routine supplementation with folic acid (the synthetic form of folate) is universally recommended. Routine supplementation with iron is recommended in areas of the world with high rates of malnutrition and anemia; in the US and other developed nations, the need for iron supplementation is generally evaluated by a healthcare professional on an individual basis.

Condition Overview

Nutrient needs during pregnancy are increased. This is because the mother requires extra energy, building blocks, and cellular assistants to support the development and growth of the new baby. Increased nutrient needs during pregnancy are met by a combination of physiological adaptations and increased dietary intake by the mother.

Physiological adaptations

1. Hormonal changes - hormonal changes during pregnancy help to direct nutrients to the developing fetus. Hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), and estrogen stimulate maternal fat breakdown, increase bone turnover, and oppose the action of insulin. Overall, these changes allow glucose, amino acids, fatty acids, and micronutrients to flow to the developing fetus rather than being stored in maternal tissues.

2. Increased absorption and reduced excretion - alterations in nutrient absorption and excretion also help the mother meet the increased nutrient demands of pregnancy. For example, gastrointestinal absorption of calcium, iron, zinc, and vitamin B12 are increased compared to that of nonpregnant women. Pregnant women also reduce the amount of selenium excreted in the urine.

3. Mobilization of mineral stores - the mother can access stores of calcium (from the skeleton) and iron (from a storage protein called ferritin) to meet the demands of the developing fetus. Maternal stores of calcium and iron can be replenished by ingesting these micronutrients at the recommended levels of intake (Table 2).

Dietary intake

1. Energy (calories) - energy requirements increase by an estimated 300 kcal/day during the second and third trimesters of pregnancy, when the baby is rapidly increasing in size. Because the requirement for most micronutrients increases more than the requirement for energy, women are advised to improve diet quality and get sufficient exercise during pregnancy in order to meet micronutrient requirements while maintaining a healthy weight. Appropriate weight gain during pregnancy (neither too little nor too much) helps to improve maternal and child health outcomes (Table 1).

Table 1. Weight Gain Guidelines from the Institute of Medicine
  Prepregnancy BMI (kg/m2) Estimated Weight Gain
Underweight less than 18.5 28-40 lb (12.7-18.1 kg)
Normal weight 18.5-24.9 25-35 lb (11.3-15.9 kg)
Overweight 25-29.9 15-25 lb (6.8-11.3 kg)
Obese 30 and greater 11-20 lb (5.0-9.1 kg)
SOURCE: Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines; Rasmussen KM, Yaktine AL, editors. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington (DC): National Academies Press (US); 2009. Summary. 

2. Water - The fluid found inside and around our cells, tissues, and organs is critical for our body’s ability to function — body water maintains our blood volume, helps transport nutrients and remove waste products, regulates body temperature, and is a critical component of every cell in our body. During pregnancy, extra fluid is needed to maintain the amniotic fluid that surrounds, cushions, and protects the developing fetus and to support an increase in maternal blood volume. Adequate fluid intake also helps combat fluid retention, constipation, and dehydration. The recommended intake for total water is 3 liters (12.7 cups)/day from drinking water, beverages, and food; of this amount, about 10 cups/day should come from water and other beverages.

3. Macronutrients (protein, carbohydrate, fat)

  • Protein - protein needs increase by approximately 25 additional grams/day; many women already consume this amount of protein. Good protein sources include low-fat dairy products, lean meat and poultry, fish, eggs, legumes, nuts, and seeds.
  • Carbohydrate - carbohydrate intake should be at least 175 grams/day. The majority of carbohydrate intake should come from whole grain breads and cereals, fruit, vegetables, and legumes.
  • Fat - consumption of the right kind of fat is important. Pregnant and nonpregnant women alike should replace saturated and trans fat with mono- and polyunsaturated fat from vegetable oils, nuts, and oily fish. By consuming the recommended amounts of the essential fatty acids, linoleic acid (omega-6 PUFA) and α-linolenic acid (omega-3 PUFA) (Table 2), pregnant women will meet their needs for other fatty acids, such as arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

4. Micronutrients (vitamins, nutritionally essential minerals, and choline) - For several micronutrients, the recommended levels of intake are increased compared to nonpregnant women of the same age (Table 2). Considering that many women do not meet the recommended levels of intake for many micronutrients to begin with, special effort should be made to meet the higher nutrient needs of pregnancy. This includes making healthful dietary choices and possibly taking a dietary supplement under the supervision of a qualified healthcare provider.

Table 2 also includes the tolerable upper intake level (UL) for pregnant adult women. The UL is the highest level of daily intake that is likely to pose no risk of adverse health effects in almost all individuals of a specified life stage. While intakes above the UL are not advised for any micronutrient, vitamin A excess during pregnancy can be particularly detrimental, causing heart defects and facial malformations in the newborn.

Table 2. Nutrient Requirements during Pregnancy
Nutrient (units) RDA or AI* Nonpregnant Adult (19-50y) RDA or AI* Pregnant Adult UL Pregnant Adult
Vitamins      
Biotin (µg/d) 30 30  
Folate (µg/d) 400 600 1,000 folic acid
Niacin (mg/d) 14 18 35
Pantothenic acid (mg/d) 5* 6*  
Riboflavin (mg/d) 1.1 1.4  
Thiamin (mg/d) 1.1 1.4  
Vitamin A (µg/day) 700 770 3,000
Vitamin B6 (mg/d) 1.3 1.9 100
Vitamin B12 (µg/d) 2.4 2.6  
Vitamin C (mg/d) 75 85 2,000
Vitamin D (µg/d) 15 (600 IU) 15 (600 IU) 100 (4,000 IU)
Vitamin E (mg/d) 15 15 1,000
Vitamin K (µg/d) 90* 90*  
Minerals      
Calcium (mg/d) 1,000 1,000 2,500
Chloride (g/d) 2.3* 2.3* 3.6
Chromium (µg/d) 25* 30*  
Copper (µg/d) 900 1,000 10,000
Fluoride (mg/d) 3* 3* 10
Iodine (µg/d) 150 220 1,100
Iron (mg/d) 18 27 45
Magnesium (mg/d) 310 (19-30y); 320 (31-50y) 350 350 supplemental magnesium
Manganese (mg/d) 1.8* 2* 11
Molybdenum (µg/d) 45 50 2,000
Phosphorus (mg/d) 700 700 3,500
Potassium (g/d) 4.7* 4.7*  
Selenium (µg/d) 55 60 400
Sodium (g/d) 1.5* 1.5* 2.3
Zinc (mg/d) 8 11 40
Other      
Choline (mg/d) 425* 450* 3,500
n-6 PUFA, linoleic acid (g/d) 12* 13*  
n-3 PUFA, α-linolenic acid (g/d) 1.1* 1.4*  
Abbreviations: RDA, Recommended Dietary Allowance; AI, Adequate Intake; UL, Tolerable Upper Intake Level; µg, micrograms; mg, milligrams; g, grams; d, day; y, years; PUFA, polyunsaturated fatty acid

References

Nutrition Research

DEFINITIONS
Test tube (in vitro) experiment - a research experiment performed in a test tube, culture dish, or other artificial environment outside of a living organism; in vitro is a Latin phrase meaning in glass
Animal experiment - a research experiment performed in a laboratory animal; many different animal species are studied in the laboratory, including terrestrial (land), aquatic (water), and microscopic animals
Observational study - a human research study in which no experimental intervention or treatment is applied, and participants are simply observed over time
Randomized controlled trial - a human research study in which participants are assigned by chance alone to receive either an experimental agent (the treatment group) or a placebo (the control group)
Placebo - a chemically inactive substance

Essential Fatty Acids

What they do

General

  • Essential fatty acids are a type of polyunsaturated fatty acid (PUFA) that cannot be synthesized in the body and must come from the diet.
  • Essential fatty acids are structural components of every cell in the body and are converted to compounds that influence inflammation and immunity.
  • There are two classes of essential fatty acids: omega-6 PUFA and omega-3 PUFA.

Pregnancy-specific

  • The last trimester of pregnancy and first six months of postnatal life are critical periods for the accumulation of the long-chain omega-3 PUFA, docosahexaenoic acid (DHA), in the brain and retina of the baby.
What we know
  • Higher intakes of long-chain omega-3 PUFA from fish and seafood during pregnancy are associated with improved developmental outcomes in offspring.
  • Fetal tissue can form DHA from the omega-3 PUFA α-linolenic acid. If the maternal diet meets omega-3 PUFA (α-linolenic acid) and omega-6 PUFA (linoleic acid) requirements, supplementation with DHA provides no further benefit to the fetus.
  • Supplementation with long-chain omega-3 PUFA during pregnancy does not influence the risk of preterm birth, gestational diabetes mellitus, pregnancy-induced hypertension, or preeclampsia.
  • There is some evidence that long-chain omega-3 PUFA supplementation may result in a modest increase in the length of gestation (1.6 days), especially in women with low omega-3 PUFA consumption.
DEFINITIONS
Gestational diabetes mellitus - high blood glucose during pregnancy
Pregnancy-induced hypertension - abnormally high blood pressure (>140/90 mm Hg) that develops after the twentieth week of pregnancy
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling
HIGHLIGHT
  • The potential benefits associated with obtaining long-chain omega-3 PUFA through moderate consumption of fish (one to two servings/week) during pregnancy outweigh any risks of contaminant exposure.
  • Fish with high levels of mercury (tilefish from the Gulf of Mexico, shark, swordfish, and king mackerel) should be avoided.
  • Consumption of white (albacore) tuna should be limited to 6 ounces/week.
  • See The US Food and Drug Administration for detailed advice on fish consumption.

For references and more information, see the sections on Visual and neurological development and Gestation and pregnancy in the Essential Fatty Acids article.

There are two essential fatty acids: linoleic acid (an omega-6 polyunsaturated fatty acid) and alpha-linolenic acid (an omega-3 polyunsaturated fatty acid). These fatty acids are considered essential nutrients because they cannot be made in the body and must be consumed in the diet. Vegetable oils, especially safflower oil, sunflower oil, and corn oil, are a good source of linoleic acid.Flax and chia sees, walnuts, canola oil, and soybean oil are good sources of alpha-linoleic acid. Inside body tissues, the essential fatty acids are converted to long-chain fatty acids. Due to low efficiency of conversion, it is recommended to obtain eicosapentaenoic acid (EPA) and docosapentaenoic acid (DHA) from additional sources. Oily fish, fish oil supplements, krill oil supplements, and algae oil supplements are good sources of EPA and DHA.

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Biotin

What it is

General

  • Biotin is a B-vitamin that helps make and breakdown glucose, fatty acids, and some amino acids.

Pregnancy-specific

  • During pregnancy, biotin is needed for these same essential cellular activities, which are taking place at higher rates during fetal development.
What we know
  • A substantial number of pregnant women (30 to 50 percent) have an increased urinary excretion of 3-hydroxyisovaleric acid (3-HIA), a marker of biotin status. It is not known whether this increase in urinary 3-HIA excretion is normal for pregnant women or indicative of low biotin intake relative to need.
  • Although some animals are very sensitive to biotin deficiency during pregnancy, a link between biotin deficiency and adverse effects in the mother and the developing fetus have not been observed in humans.
  • The recommended level of biotin intake (30 micrograms/day) is the same for pregnant and nonpregnant women (Table 2). It is estimated that a typical mixed diet provides 30 to 60 micrograms of biotin/day.

For references and more information, see the section on Biotin in the Pregnancy and Lactation article.

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Calcium

What it is

General

  • Calcium is an essential mineral that is a structural component of bones and teeth, is required for proper nerve transmission and muscle contraction, and influences blood pressure.

Pregnancy-specific

  • Approximately 250-350 milligrams (mg)/day of calcium is transferred from the mother to the fetus, primarily in the last trimester.
  • Low-calcium intake during pregnancy may cause hormonal changes that lead to smooth muscle cell contraction, blood vessel narrowing, and the retention of sodium and fluid. These changes can contribute to the development of pregnancy-induced hypertension (PIH) and preeclampsia.
What we know
  • Intestinal calcium absorption efficiency doubles during pregnancy, and the mineral can be temporarily mobilized from the skeleton to support fetal needs for calcium.
  • Observational studies suggest an inverse relationship between dietary calcium intake and the occurrence of PIH. In other words, the lower the calcium intake, the higher the risk of developing PIH.
  • Randomized controlled trials report that calcium supplementation during pregnancy (more than 1,000 mg/day) is associated with a 35 percent lower risk of high blood pressure and 55 percent lower risk of preeclampsia; the risk reduction for preeclampsia is even stronger for women considered to be at high risk for the condition (78 percent lower risk) and women with low dietary intake of calcium (64 percent lower risk).
  • Although the RDA for calcium is the same for pregnant and nonpregnant women, calcium is considered a shortfall nutrient in the diet and many women do not meet the recommended 1,000 mg/day.
DEFINITIONS
Pregnancy-induced hypertension - abnormally high blood pressure (>140/90 mm Hg) that develops after the twentieth week of pregnancy
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling

For references and more information, see the section on Calcium in the Pregnancy and Lactation article.

Calcium Flashcard. Main Functions: 1) structural component of bones and teeth, 2) regulates nerve transmission and muscle contraction, 3) helps maintain a healthy blood pressure, and 4) helps maintain acid-base balance in the blood. Good Sources: dairy (yogurt, milk, cheese), plain yogurt, 8 ounces or 1 cup = 415 mg; sardines (canned) 1 can or 3.75 ounces = 351 mg; green leafy vegetables (kale, bok choy), collard greens (cooked), one-half cup = 300 mg; mg= milligrams. Daily Recommendation: 1,000 mg for men 19-70 years, 1,200 mg for men 71+ years; 1,000 mg for women 19-50 years, 1,200 mg for women 51+ years. Special Notes: 1) Many Americans do not consume enough calcium. Just 3 servings of dairy per day would meet the recommendation. For those who don't consume dairy, calcium-fortified juices, cereals, and milk alternatives are a good substitute. 2) To maximize absorption from supplements, take no more than 500 mg at a time.

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Choline

What it does

General

  • Choline is an essential component of cell membranes, influences the production of several important neurotransmitters, and helps transport and metabolize fatty acids and cholesterol.
  • Additionally, choline helps convert homocysteine to methionine, an amino acid used in countless essential cellular activities.
  • Choline can be made by the body in small amounts but not enough to support health. Therefore, choline must also be obtained from dietary sources and is considered an essential nutrient.

Pregnancy-specific

  • Choline is needed for embryonic and fetal brain development.
  • Animal studies indicate that maternal intake of choline during pregnancy might affect intellectual abilities in the offspring.
What we know
  • The mother delivers large amounts of choline to the fetus across the placenta, placing an increased demand on maternal stores of choline during pregnancy.
    • high levels of estrogen during pregnancy lead to increased choline production.
    • pregnant women are encouraged to consume choline-rich foods, such as eggs, meat, and seafood.
  • The relationship between choline and the risk of neural tube defects is unclear at this time.
    • There have been some reports that low dietary intake or low blood concentrations of choline are associated with a higher risk of NTDs; other reports have found no association.
    • It is not known if supplementation with choline will lower the occurrence of NTDs.
DEFINITIONS
Neural tube defects (NTDs) - a group of malformations that occur to the neural tube (the precursor to the brain and spinal cord) during embryonic development

For references and more information, see the section on Choline in the Pregnancy and Lactation article.

Choline Flashcard. Main functions: 1) structural component of all cell membranes, 2) transport and metabolism of fat and cholesterol, 3) helps make some important neurotransmitters, and 4) helps maintain normal levels of homocysteine in the blood. Good sources: egg (1 large), 147 mg; meat (beef and poultry), beef (3 ounces), 97 mg; seafood (fish and shellfish), scallop (steamed, 3 ounces) 94 mg (mg=milligrams; a three-ounce serving of meat or fish is about the size of a deck of cards; Daily Recommendation: 550 mg for all men and 425 mg for all women; Special Notes: 1) Choline can be made in the body, but it is not enough to support health. Therefore, it must also be consumed in the diet. 2) A varied diet should provide enough choline for most people, but strict vegetarians who don't consume milk or eggs may be at risk of inadequate choline intake.

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Chromium

What it does

General

  • Chromium is a mineral that enhances the action of insulin.

Pregnancy-specific

  • Chromium supplementation is being investigated for the control of blood glucose in type 2 diabetes mellitus; the role of chromium supplementation in gestational diabetes mellitus (GDM) is also under investigation.
What we know
  • Observational studies report mixed results regarding serum chromium concentration and GDM.
    • Two studies found no relationship; one study found that women with GDM have lower serum chromium concentration compared to pregnant women without GDM.
    • Further complicating matters, it is not known if serum chromium concentration accurately reflects tissue chromium levels or chromium status during pregnancy.
  • One small randomized controlled trial in 24 women with GDM found that supplementation with chromium picolinate reduced fasting blood glucose and insulin levels. Importantly, insulin therapy was still required to normalize elevated blood glucose in this study population.
  • More research is needed to determine whether chromium supplementation is useful in the treatment of GDM.
DEFINITIONS
Gestational diabetes mellitus - high blood glucose during pregnancy

For references and more information, see the section on Chromium in the Pregnancy and Lactation article.

 

Folate (folic acid)

What it does

General

  • Folate is a B-vitamin required for DNA synthesis and the formation of new cells.
  • Additionally, the B-vitamins folate, vitamin B12, and vitamin B6 work together to convert homocysteine to methionine, an amino acid used in countless essential cellular activities.
  • Folate is present naturally in food; folic acid is a synthetic form of folate that is found in supplements and fortified products. Although folic acid is better absorbed across the digestive tract, both forms enter the same biochemical pathway and are indistinguishable at the cellular level.

Pregnancy-specific

  • The developing fetus requires folate to form new cells, tissues, and organs.
  • An especially sensitive event that relies on a sufficient amount of folate is the closure of the neural tube, the precursor to the brain and spinal cord. Closure of the neural tube occurs very early in pregnancy, by the sixth week of gestation, a time when many women do not realize they are pregnant.
What we know
  • Lower blood folate concentrations are associated with a higher risk of neural tube defects (NTDs).
  • Randomized controlled trials demonstrate that periconceptional supplementation with folic acid dramatically reduces the occurrence of NTDs.
  • In order to reduce the risk of NTDs, there is wide agreement that all women capable of becoming pregnant take supplemental folic acid. The US Preventive Services Task Force recommends a daily supplement of 400 to 800 micrograms of folic acid for all women planning or capable of pregnancy.
  • Women who have had a previous NTD-affected pregnancy may be advised to consume up to 4,000 micrograms/day of folic acid when they are planning to become pregnant. This dosage should be prescribed and monitored by a healthcare provider.
  • Throughout pregnancy, low blood folate concentrations may be associated with other adverse pregnancy outcomes. Elevated blood homocysteine, an indicator of low folate status, has been associated with an increased risk of preeclampsia, premature delivery, and low birth weight. For this reason, folic acid supplementation should continue throughout pregnancy. 
DEFINITIONS
Gestation - the period of development from conception until birth.
Neural tube defects (NTDs) - a group of malformations that occur to the neural tube (the precursor to the brain and spinal cord) during embryonic development
Periconceptional - the period of time about one month before conception until the end of the first trimester 
Conception - the point at which a woman’s egg is fertilized with a man’s sperm
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling

For references and more information, see the section on Adverse pregnancy outcomes in the Folate article.

Folate Flashcard. Main Functions: 1) required for DNA synthesis, 2) supports cell growth and repair, 3) helps prevent neural tube defects. Good Sources: legumes (beans, peas, lentils), lentils (cooked) one-half cup = 179 micrograms dietary folate equivalents (DFE); green leafy vegetables (kale, spinach), spinach (cooked) one-half cup, 131 micrograms DFE; fortified food and supplements, sliced bread (enriched), 1 slice, 84 micrograms DFE. Daily Recommendation: 400 micrograms DFE for adults, 600 micrograms DFE for pregnant women. Special Notes: 1) Folate is a general term that refers to both natural folates in food and folic acid, the synthetic form used in supplements and fortified food. 2) DFE = a unit of measure that accounts for differences in the absorption of naturally occurring food folate and synthetic folic acid. 3) To reduce the risk of neural tube defects, all women capable of becoming pregnant should consume 400 micrograms of folic acid daily in addition to the folate obtained from a varied diet. 4) Very high-dose folic acid supplementation (5,000 micrograms) can mask a vitamin B12 deficiency, specifically signs of nerve damage.

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Iodine

What it does

General

  • Iodine is a mineral that is a major structural component of thyroid hormones. Thyroid hormones regulate many key metabolic and enzymatic reactions that are essential for life.

Pregnancy-specific

  • Iodine is needed for maternal thyroid hormone production.
  • During pregnancy, thyroid hormone is needed for myelination of the central nervous system and is essential for normal brain development.
What we know
  • Maternal iodine deficiency has been associated with increased incidence of miscarriage, stillbirth, and birth defects.
  • Severe iodine deficiency during pregnancy can result in hypothyroidism and brain damage and mental deficiency in the offspring.
  • Even mild forms of maternal iodine deficiency may have adverse effects on intellectual development and mental abilities in the offspring.
  • The requirement for iodine is significantly increased during pregnancy, from 150 to 220 micrograms/day.
    • Universal salt iodization has helped to dramatically reduce iodine deficiency worldwide.
    • Still, to ensure the higher requirement is met, the American Thyroid Association recommends that women take a multivitamin containing 150 micrograms of iodine daily during preconception, pregnancy, and lactation.
DEFINITIONS
Myelination - the accumulation of a fatty layer around nerve cells
Hypothyroidism - low concentration of thyroid hormone in the blood

For references and more information, see the section on Iodine in the Pregnancy and Lactation article.

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Iron

What it does

General

  • Iron is required for the synthesis of hundreds of essential proteins, facilitates oxygen transport and storage, participates in energy production, and assists antioxidant enzymes.
  • Dietary iron is found in two forms: heme and nonheme iron. Heme iron comes mainly from meat, poultry, and seafood. Nonheme iron is found in plants, dairy products, meat, fortified food, and dietary supplements.

Pregnancy-specific

  • The developing fetus needs iron for the growth and development of all tissues and organs.
  • The mother requires iron to meet the increased production of red blood cells that transport oxygen to the developing fetus; too little iron can lead to iron-deficiency anemia.
What we know
  • The requirement for iron is significantly increased during pregnancy, from 18 to 27 milligrams (mg)/day.
  • Intestinal absorption of dietary iron increases during the second and third trimesters, yet many women still develop iron deficiency or iron-deficiency anemia during pregnancy.
  • Severe iron deficiency during pregnancy has been associated with increased risk of low-birth-weight infants, premature delivery, and infant mortality.
  • In developing countries, where anemia is widespread and there is a high risk of anemia among pregnant women, routine iron supplementation reduces the risk of iron-deficiency, anemia, preterm delivery, and low-birth-weight infants. Doses above 60 mg/day of elemental iron are associated with an increased risk of side effects.
  • In developed countries, where there is an average risk of anemia among pregnant women, supplementation with iron improves maternal iron status and decreases the risk of anemia at term.
DEFINITIONS
Anemia - a condition characterized by low concentration of hemoglobin
Hemoglobin - the oxygen-carrying component of red blood cells
Iron-deficiency anemia - a lack of iron in the body leads to decreased production of hemoglobin
HIGHLIGHT: IRON SUPPLEMENTS
  • Most women will require iron supplements to meet the increased requirement during pregnancy. The requirement during pregnancy is 27 mg iron/day, yet dietary surveys indicate that the average intake among pregnant women in the US is 15 mg/day.
  • Reversible, gastrointestinal side effects (nausea, constipation, vomiting, and diarrhea) are associated with the use of high-dose (≥ 60 mg/day) iron supplements.
  • In general, iron supplements are better absorbed on an empty stomach and with vitamin C, either from food or supplements.
  • Take iron supplements separate (several hours apart) from single-dose calcium and zinc supplements.
  • Do not take iron supplements with coffee, tea, bran, or milk.

For references and more information, see the section on Iron in the Pregnancy and Lactation article.

Iron Flashcard. Main Functions: 1) Helps make healthy red blood cells that transport oxygen throughout the body, 2) Critical for normal immune function, 3) Structural component of hundreds of essential molecules, and 4) Assists antioxidant enzymes. Good Sources: There are two forms of dietary iron: heme iron and nonheme iron. Heme iron is found in red meat, poultry, and fish. 3 ounces of red meat contains 2.3 mg of heme iron. Nonheme iron is found in lentils, vegetables, and fortified food. One-half cup of cooked lentils contains 3.3 mg of nonheme iron. Daily Recommendation: 8 mg for adult men, 18 mg for women 19-50 years, 8 mg for women 51 years and older. Special Notes: 1) Heme iron is better absorbed than nonheme iron; the absorption of nonheme iron is enhanced by vitamin C. 2) National dietary surveys indicate that iron is underconsumed by adolescent and premenopausal females. 3) The Daily Recommendation for iron is significantly increased during pregnancy (from 18 to 27 mg/day), yet dietary surveys indicate that the average intake among pregnant women in the US is 15 mg/day. 4) Iron is efficiently recycled by the body. Premenopausal women have higher requirements due to menstrual losses.

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Magnesium

What it does

General

  • Magnesium is an essential mineral that serves as a structural component of the skeleton; assists in hundreds of enzymatic reactions involved in the synthesis of energy, DNA, and proteins; and is required for proper nerve conduction and muscle contraction.

Pregnancy-specific

  • Magnesium is needed for essential enzymatic reactions and the formation of new tissue (including bone) that takes place during embryonic and fetal development.
  • Intravenous magnesium sulfate is included in the medical care of preeclampsia, eclampsia, and neuroprotection of premature infants.
What we know
  • The RDA for magnesium is slightly increased during pregnancy, from 310 to 350 milligrams (mg)/day.
    • Magnesium is considered a shortfall nutrient in the diet, meaning that magnesium is underconsumed by eating the typical American diet.
    • Good sources of magnesium include green leafy vegetables, whole grains, and nuts.
  • Regarding the medical management of certain pregnancy complications, intravenous magnesium sulfate causes blood vessel dilation in the brain and periphery and is used by physicians to prevent seizures that may occur in association with preeclampsia-eclampsia in late pregnancy or during labor.
DEFINITIONS
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling
Eclampsia - progression of preeclampsia causing seizures and an increased risk of hemorrhage

For references and more information, see the section on Pregnancy complications in the Magnesium article.

Magnesium Flashcard. Main Functions: 1) Structural component of bones and teeth, 2) Regulates nerve transmission and muscle contraction, and 3) Assists in hundreds of essential cellular reactions. Good Sources: Whole Grains (wheat, oats, barley), brown rice, cooked, 1 cup = 86 mg; Green Leafy Vegetables (Swiss chard, spinach), spinach (boiled), 1 cup = 157 mg; Nuts (hazelnuts, cashews), almonds, 1 ounce or 23 almonds = 77 mg. Daily Recommendation: 400 mg for men 19-30 years, 420 mg for men 31 years and older; 310 mg for women 19-30 years, 320 mg for women 31 years and older. Special Notes: 1) Most people consume too little magnesium. 2) The Tolerable Upper Intake Level (UL) for magnesium is 350 mg/day from supplements. The UL does not apply to naturally occurring magnesium from food.

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Riboflavin

What it does

General

  • Riboflavin is a B-vitamin that helps convert food into useable energy and assists several metabolic and antioxidant enzymes.

Pregnancy-specific

  • Riboflavin is needed to support the increased growth and energy utilization that occurs during pregnancy.
  • While it is unclear what causes preeclampsia during pregnancy, riboflavin deficiency could compromise antioxidant enzyme activity, leading to oxidative stress and an increased risk of preeclampsia.
What we know
  • Very few studies have investigated the link between riboflavin and preeclampsia.
    • One observational study in pregnant women at high risk for preeclampsia found that those who were riboflavin deficient were 4.7 times more likely to develop preeclampsia than those who had adequate riboflavin nutritional status.
    • One small randomized controlled trial in pregnant women at high risk for preeclampsia found that supplementation with 15 mg riboflavin daily did not prevent preeclampsia.
  • The RDA for riboflavin is slightly increased during pregnancy, from 1.1 to 1.4 milligrams (mg)/day.
    • Most plant and animal food contains riboflavin.
    • Dietary surveys indicate that usual intake among Americans (≥4 years of age) is 2.2 mg/day. 
DEFINITIONS
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling

For references and more information, see the section on Deficiency in the Riboflavin article.

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Vitamin A

What it does

General

  • Vitamin A is a fat-soluble vitamin that is essential for normal vision, reproduction, cell growth and development, and immune function.
  • Preformed vitamin A (retinol) is found in animal organs and fortified products.
  • Provitamin A carotenoids (α-carotene, β-carotene, and β-cryptoxanthin) are compounds found in yellow- and orange-colored fruit and vegetables that are converted to retinol by the liver.

Pregnancy-specific

  • Vitamin A is involved in cellular events that regulate the formation of the vertebrae and spinal cord, vital organs (such as the heart and lungs), eyes, ears, and limbs. Severe vitamin A deficiency in animal models results in birth defects to these structures.
  • Vitamin A deficiency impairs iron mobilization from stores, impairs the synthesis of hemoglobin, and may exacerbate iron-deficiency anemia.
  • Because vitamin A is also required for normal functioning of the retina, dim-light vision, and color vision, vitamin A deficiency can lead to impaired dark adaptation (night blindness) and in severe cases, blindness.
What we know
  • Vitamin A deficiency during pregnancy has been linked to impaired immunity, increased susceptibility to infection, increased risk of maternal death and disease, and night blindness.
    • In regions of the world where vitamin A deficiency is a severe public health problem (mainly Africa and Southeast Asia), the World Health Organization (WHO) recommends vitamin A supplementation (up to 10,000 IU daily or 25,000 IU weekly) starting in the second or third trimester for the prevention of night blindness.
    • In developing countries, co-supplementation with vitamin A and iron may be more effective in reducing iron-deficiency anemia than iron supplementation alone.
  • Consumption of excess preformed vitamin A during pregnancy can cause birth defects.
    • The most critical period for damage appears to be during the first trimester, resulting in birth defects affecting the cardiovascular system, central nervous system, facial area, and thymus (an organ involved in immune cell production).
    • Birth defects have not been observed at supplemental doses less than 3,000 micrograms (10,000 IU)/day of preformed vitamin A.
DEFINITIONS
Anemia - a condition characterized by low concentration of hemoglobin
Hemoglobin - the oxygen-carrying component of red blood cells
Iron-deficiency anemia - a lack of iron in the body leads to decreased production of hemoglobin
HIGHLIGHT
  • The slightly increased need for vitamin A during pregnancy (from 700 to 770 micrograms/day) can be met by consuming a varied and balanced diet and by consuming β-carotene, which is converted to vitamin A in the body and has not been associated with birth defects.
  • In the US, vitamin A is considered a shortfall nutrient in the diet and many women do not meet the recommended 700 micrograms/day.
  • Because a number of foods in the US are fortified with preformed vitamin A, the Linus Pauling Institute recommends that pregnant women avoid multivitamin or prenatal supplements that contain more than 750 micrograms (2,500 IU) of preformed vitamin A (retinol).

For references and more information, see the section on Vitamin A in the Pregnancy and Lactation article.

Vitamin A (retinol) Flashcard. Main Functions: 1) Essential for site, dim-light adaptation, and color vision; 2) Supports reproductive health for both men and women; 3) Required for proper immune function; 4) Influences cell growth and development. Good Sources: There are two forms of dietary vitamin A: preformed vitamin A from animal products and provitamin A carotenoids from fruit and vegetables. Preformed Vitamin A: cod liver oil, 1 teaspoon = 1,350 micrograms retinol activity equivalents (RAE), 1 large egg = 80 micrograms RAE. Provitamin A (yellow & orange fruit & vegetables), sweet potato (baked), 1 cup = 1,922 micrograms RAE. Daily Recommendation: 900 micrograms RAE for men and 700 micrograms RAE for women. Special Notes: 1) RAE = a unit of measure for the vitamin A content of food. It reflects the amount of active vitamin A provided by the different types of food sources. 2) It is possible to ingest too much vitamin A (retinol). The Tolerable Upper Intake Level (UL) is 3,000 micrograms RAE of retinol/day. 3) There is no UL for provitamin A carotenoids because the liver controls their conversion to retinol.

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Vitamin B6

What it does

General

  • Vitamin B6 helps convert food into usable energy and assists in the formation of neurotransmitters, red blood cells, proteins, and DNA.
  • Additionally, the B-vitamins folate, vitamin B12, and vitamin B6 work together to convert homocysteine to methionine, an amino acid used in countless essential cellular activities.

Pregnancy-specific

  • Because a developing embryo and fetus have high rates of proliferation, they require vitamin B6 to form new cells, tissues, and organs.
  • Vitamin B6 has been used since the 1940s to treat nausea during pregnancy.
What we know
  • Short-term supplementation with high-dose vitamin B6 (10 mg/day) may help relieve nausea in pregnancy.
  • The American and Canadian Colleges of Obstetrics and Gynecology recommend the use of a delayed-release formulation of pyridoxine hydrochloride (vitamin B6) plus doxylamine succinate (an antihistamine) as first-line therapy for nausea and vomiting during pregnancy (NVP). Such therapy should be conducted under the care of a qualified healthcare provider.
DEFINITION
Proliferation - an increase in the number or amount of something

For references and more information, see the section on Morning sickness in the Vitamin B6 article.

Vitamin B6 Flashcard. Main Functions: 1) helps convert food into energy, 2) helps make red blood cells, 3) helps maintain normal levels of homocysteine in the blood. Good Sources: Fish (slamon, tuna, halibut), wild salmon, 3 ounces, 0.5-0.8 mg; poultry (turkey, chicken, duck), light-meat turkey (cooked), 3 ounces = 0.7 mg; nuts (hazelnuts, walnuts) pistachio nuts, 1 ounce or 47 pistachios = 0.5 mg. Daily Recommendation: 2 mg for all adults. Special Notes: 1) The Daily Recommendation listed is specific to the LPI based on extensive review of the scientific evidence. The Institute of Medicine's Recommended Dietary Allowance (RDA) is 1.3 mg/day for adults 19-50 years, 1.7 mg/day for men 51 years and older, and 1.5 mg/day for women 51 years and older. 2) In the US, vitamin B6 is added back to refined grains. Therefore, enriched products are also a source of vitamin B6. 3) Excessive supplementation of vitamin B6 (more than 100 mg/day) can cause nerve damage and skin lesions.

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Vitamin B12

What it does

General

  • Vitamin B12 helps convert food into usable energy, is required for proper nerve function, and assists in the formation of red blood cells, proteins, and DNA.
  • Additionally, the B-vitamins folate, vitamin B12, and vitamin B6 work together to convert homocysteine to methionine, an amino acid used in countless essential cellular activities.

Pregnancy-specific

  • Because a developing embryo and fetus have high rates of proliferation, they require vitamin B12 to form new cells, tissues, and organs.
What we know
  • Absorption of vitamin B12 is more efficient during pregnancy.
  • Inadequate dietary intake of vitamin B12 causes elevated homocysteine levels, which has been associated with adverse pregnancy outcomes, such as preeclampsia, premature delivery, low birth weight, very low birth weight, and stillbirth.
  • Low serum levels of vitamin B12 during pregnancy have been linked to an increased risk for neural tube defects (NTDs). However, the effect of vitamin B12 supplementation on the risk of NTDs has not yet been evaluated in randomized controlled trials.
  • To ensure a daily intake of 6 to 30 micrograms of vitamin B12 in a form that is easily absorbed, the Linus Pauling Institute recommends that women who are planning a pregnancy take a daily multivitamin supplement or eat a breakfast cereal fortified with vitamin B12.
DEFINITION
Proliferation - an increase in the number or amount of something
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling
Neural tube defects (NTDs) - a group of malformations that occur to the neural tube (the precursor to the brain and spinal cord) during embryonic development

For references and more information, see the section on Vitamin B12 in the Pregnancy and Lactation article.

Vitamin B12 (cobalamin) Flashcard. Main Functions: 1) Helps make red blood cells, 2) Required for proper nerve function, and 3) Helps maintain normal levels of homocysteine in the blood. Good Sources: Vitamin B12 is only found in animal products. Seafood (shellfish, fish), clams (steamed) 3 ounces = 84 micrograms; poultry (turkey, chicken, duck), roasted turkey, 3 ounces = 0.8 micrograms; red meat (beef, pork, lamb), lean beef plate steak (grilled), 3 ounces = 6.9 micrograms. Daily Recommendation: adults 19-50 years = 2.4 micrograms; LPI recommends older adults (51 years and older) take 100-400 micrograms of supplemental vitamin B12. Special Notes: 1) Over-the-counter antacids reduce vitamin B12 absorption. 2) The capacity to absorb vitamin B12 from food goes down with age. 3) Symptoms of vitamin B12 deficiency include tingling and numbness in the extremities, nerve damage, and memory loss. 4) Older adults and individuals consuming a vegan diet should obtain vitamin B12 from supplements or fortified food.

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Vitamin C

What it does

General

  • Vitamin C is a water-soluble vitamin that neutralizes a variety of reactive oxygen species, recycles important cellular antioxidants, augments the functional activity of immune cells, and helps make collagen, L-carnitine, and several neurotransmitters.

Pregnancy-specific

  • Vitamin C is required to make collagen, a component of skin, blood vessels, tendons, and the organic matrix of bone.
  • Oxidative stress has been implicated in the development of preeclampsia; thus, antioxidant vitamins (vitamin C and vitamin E) may be important in preventing the condition.
What we know
  • Randomized controlled trials have not found combined supplementation of antioxidant vitamins (1,000 mg/day vitamin C plus 400 IU/day vitamin E (RRR-α-tocopherol) to be effective in preventing preeclampsia.
DEFINITIONS
Reactive oxygen species (ROS) - highly unstable oxygen-containing compounds that react easily with nearby cellular structures, potentially causing damage
Antioxidant - a compound that prevents or repairs the damage caused by reactive oxygen species
Oxidative stress - a situation in which the production of reactive oxygen species exceeds the ability of an organism to eliminate or neutralize them
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling

For references and more information, see the section on Vitamin C and Vitamin E in the Pregnancy and Lactation article.

Vitamin C (ascorbic acid) Flashcard. Main Functions: 1) Antioxidant defense, 2) Enhances immune function, 3) Needed to make collagen, carnitine, and the neurotransmitters serotonin and norepinephrine. Good Sources: Fruit, 1 medium-sized kiwifruit = 90 mg; strawberries, 1 cup whole, 85 mg; Vegetables (broccoli, kale, tomatoes), sweet red pepper (one-half cup, chopped) = 95 mg. Daily Recommendation is 400 mg for all adults. Special Notes: 1) Heat destroys vitamin C. Try to eat fresh foods and cook by steaming, microwaving, or stir-frying. 2) Vitamin C in food is identical to vitamin C in supplements. 3) The Daily Recommendation listed is specific to the LPI based on extensive review of the scientific evidence. The Institute of Medicine's Recommended Dietary Allowance (RDA) is 90 mg/day for men and 75 mg/day for women.

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Vitamin D

What it does

General

  • Vitamin D is a fat-soluble vitamin that helps maintain calcium and phosphorus balance, promotes bone health, regulates immune function, and influences cell growth and development.

Pregnancy-specific

  • Vitamin D is needed for the absorption of calcium and for the formation of new tissue (mainly bone) that takes place during embryonic and fetal development.
What we know
  • Vitamin D insufficiency (defined by the Institute of Medicine as serum 25-hydroxyvitamin D between 12 to 19 nanograms [ng]/milliliter [mL]) has been linked to an increased risk for a number of adverse outcomes in the mother and the infant.
    • For the mother: gestational diabetes mellitus, preeclampsia, and bacterial vaginosis.
    • For the infant: small-for-gestational age and low birth weight.
    • Although other adverse outcomes have been examined, no significant relationship between vitamin D insufficiency and C-section, respiratory conditions, or allergies in children have been observed.
  • The requirement for vitamin D is not increased during pregnancy, but vitamin D is considered a shortfall nutrient in the diet and low vitamin D status (less than 50 nmol/L [20 ng/mL]) is common in pregnant women.
Table 3. Low Vitamin D Status is Common in Pregnant or Lactating Women
Country
Prevalence of Low Vitamin D Status in Pregnant or Lactating Women*
United States 33%
Canada 24%
United Kingdom 35%
England 31%
Spain 20%
Netherlands 44%
Germany 77%
Turkey 90%
Iran 67%
Pakistan 72%
Kuwait 70-83%
India 96%
China 69%
Vietnam 7%
Australia 48%
*Palacios C and Gonzalez L. J Steroid Biochem Mol Biol. 2014 October; 144PA:138-45
DEFINITIONS
Gestational diabetes mellitus (GDM) - high blood glucose during pregnancy
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling
HIGHLIGHT
  • The RDA for pregnant women is 600 IU (15 micrograms) vitamin D/day, the same as for non-pregnant women.
  • Vitamin D is notoriously difficult to obtain from food sources alone, and national surveys indicate that 94% of the US population is not meeting the dietary requirement for vitamin D.
  • The LPI recommends that generally healthy adults, including pregnant women, take 2,000 IU (50 micrograms) of supplemental vitamin D daily.

For references and more information, see the section on Adverse pregnancy outcomes in the Vitamin D article.

Vitamin D (calciferol) Flashcard. Main Functions: 1) Facilitates absorption of calcium and phosphorus, 2) Promotes bone health, 3) Required for proper immune function, and 4) Influences cell growth and development. Good Sources: Fatty Fish (salmon, mackerel, sardines), pink canned salmon, 3 ounces = 465 IU or 11.6 micrograms; Canned mackerel, 3 ounces = 211 IU for 5.3 micrograms; Fortified food, low-fat milk, vitamin D fortified, 8 ounces = 98 IU or 2.5 micrograms. Daily Recommendation: 600-1,000 IU (15-25 micrograms) for chldren and adolesents (4-18 years), because vitamin D is scarcely found in food, it may be necessary to take supplements. 2,000 IU or 50 micrograms for all adults, this amount applies to supplemental vitamin D, which is recommended in addition to vitamin D from a mixed diet. Special Notes: 1) The Daily Recommendation listed is specific to the LPI based on extensive review of the scientific evidence. The Institute of Medicine's Recommended Dietary Allowance (RDA) is 600 IU (15 micrograms)/day for males and females who are 4-70 years old, and 800 IU (20 micrograms)/day for all adults over 70. 2) Vitamin D is considered a "Nutrient of Public Health Concern" because underconsumption is linked to adverse health outcomes. 3) More than 90% of Americans do not meet the dietary requirement for vitamin D. 4) our bodies make vitamin D upon skin exposure to UVB radiation from the sun. Darker skin color, northern latitude, and older age impede the amount of vitamin D produced.

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Vitamin E

What it does

General

  • Vitamin E is a fat-soluble vitamin that functions as an antioxidant in lipid (fat) environments.
  • Vitamin E is an important antioxidant nutrient in cell membranes, where it functions to protect cells from damage caused by reactive oxygen species (ROS).

Pregnancy-specific

  • Oxidative stress has been implicated in the development of preeclampsia; thus, antioxidant vitamins (vitamin C and vitamin E) may be important in preventing the condition.
What we know
  • Randomized controlled trials have not found combined supplementation of antioxidant vitamins (1,000 mg/day vitamin C plus 400 IU/day vitamin E [RRR-α-tocopherol]) to be effective in preventing preeclampsia.
DEFINITIONS
Reactive oxygen species (ROS) - highly unstable oxygen-containing compounds that react easily with nearby cellular structures, potentially causing damage
Antioxidant - a compound that prevents or repairs the damage caused by reactive oxygen species
Oxidative stress - a situation in which the production of reactive oxygen species exceeds the ability of an organism to eliminate or neutralize them
Preeclampsia - abnormally high blood pressure accompanied by signs of organ damage (such as protein in the urine) and possibly edema
Edema - significant fluid retention and swelling

For references and more information, see the section on Vitamin C and Vitamin E in the Pregnancy and Lactation article.

Vitamin E (alpha-tocopherol) Flashcard. Main Functions: 1) Boosts antioxidant defense, 2) Protects cell membranes, and 3) Enhances immune function. Good Sources: vegetable oil, sunflower oil (1 tablespoon), 5.6 mg; nuts (hazelnuts, peanuts), almonds, 1 ounce or 23 almonds, 7.3 mg; avocado, 1 medium-sized, 2.7 mg. Daily Recommendation is 15 mg for all adults. Special Notes: 1) The term "vitamin E" actually refers to a family of eight coupounds. Alpha-tocopherol is the most active vitamin E compound. 2) More than 90% of Americans do not meet the dietary requirement for vitmain E. 3) Synthetic vitamin E (in supplements and fortified food) is less bioavailable than naturally occurring vitamin E from food.

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Vitamin K

What it does

General

  • Vitamin K is a fat-soluble vitamin that assists in blood clotting and modifies certain proteins to a calcium-binding form.
  • Naturally occurring vitamin K includes a number of different vitamin K compounds, classified as either vitamin K1 (phylloquinone) or vitamin K2 (menaquinones).

Pregnancy-specific

  • When taken during pregnancy, a number of medications may increase the risk of vitamin K deficiency and hemorrhagic disease in the newborn. These medications include warfarin, rifampin, isoniazid, and anticonvulsants.
  • Transfer of vitamin K across the placenta is low, therefore all infants are born with low concentrations of vitamin K.
What we know
  • Vitamin K deficiency bleeding (VKDB) develops in a small number of newborns who do not have enough vitamin K to make their blood clot.
  • Intramuscular (IM) injection of vitamin K1 to the newborn shortly after birth decreases the risk of VKDB.
  • Oral administration of vitamin K to the newborn raises serum vitamin K concentration, but is associated with an increased occurrence of late VKDB (bleeding that occurs two to 12 weeks after birth).
  • The American Academy of Pediatrics and several international organizations recommend prophylactic IM injection of vitamin K1 within six hours of birth for the prevention of VKDB.

For references and more information, see the section on Vitamin K in the Pregnancy and Lactation article.

Vitamin K Flashcard. Main Functions: 1) Assists in blood clotting, 2) promotes bone calcification, and 3) Prevents blood vessel calcification. Good Sources: There are two forms of naturally occurring vitamin K: vitamin K1 (phylloquinone) and vitamin K2 (menaquinones). Vitamin K1 sources include green leafy vegetables and plant oils, kale (raw, chopped), 1 cup=472 micrograms; canola oil, 1 tablespoon=10 micrograms; Vitamin K2 sources are fermented food and gut bacteria: there is no dietary requirement for vitamin K2 at this time.

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Zinc

What it does

General

  • Zinc is an essential trace mineral that is required for the synthesis of hundreds of essential proteins, facilitates oxygen transport, and assists several antioxidant enzymes.

Pregnancy-specific

  • Zinc is crucial for the formation, growth, and development of the cells and tissues of the developing fetus.
  • Both maternal and fetal tissues accumulate zinc over the course of pregnancy.
What we know
  • The RDA for zinc is increased during pregnancy, from 8 to 11 mg/day.
  • Poor nutritional status of zinc during pregnancy has been associated with a number of adverse outcomes, including low birth weight, premature delivery, labor and delivery complications, and birth defects.
  • Routine zinc supplementation during pregnancy reduces the risk of preterm birth in low-income women, but does not prevent other adverse pregnancy outcomes.
  • An emphasis on improving overall nutritional status rather than taking isolated zinc supplements is advised.

For references and more information, see the section on Zinc in the Pregnancy and Lactation article.

Zinc Flashcard. Main Functions: 1) Assists in the production of hemoglobin, the oxygen-carrying component of red blood cells; (2) Critical for normal immune function; and (3) Structural component of hundreds of essential molecules. Good Sources: seafood (oysters, crab), 6 medium-sized oysters (steamed) = 49.9 mg; meat (beef, dark meat, pork), rib eye steak (grilled) 3 ounces = 5.9 mg; beans (chickpeas, black beans), black beans (canned) one-half cup = 0.7 mg. Daily Recommendation; 11 mg for men and 8 mg for women. Special Notes: (1) Some dietary factors affect zinc absorption: (a) Phytates and fiber in whole grains and beans inhibit absorption, and (b) Animal-based protein enhances absorption. (2) National dietary surveys indicate that most Americans meet the dietary requirement for zinc.

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Alcoholic Beverages

What it does

General

  • Alcoholic beverages contain ethanol and other ingredients with bioactive properties that may affect health.
  • Although moderate alcohol consumption (no more than 2 drinks/day for men and 1 drink/day for women), is associated with beneficial effects in the cardiovascular system, pregnancy is a special case in which potential risks associated with alcohol consumption outweigh the benefits.

Pregnancy-specific

  • Ethanol is a teratogen, a substance that can cause abnormal development in the fetus.
  • Alcohol in the mother’s blood readily crosses the placenta to the developing embryo or fetus.
What we know
  • There is no known safe amount or safe time to drink alcohol during pregnancy.
  • Alcohol consumption, especially during the first trimester, increases the risk of preterm birth and infants born small for gestational age.
  • Moderate alcohol consumption during pregnancy has been associated with problems with memory, attention, learning, and behavior in the offspring.
  • Regular heavy alcohol consumption (>4 drinks/day) and binge drinking (4 or more drinks per occasion) during pregnancy can lead to fetal alcohol syndrome, a group of lifelong physical, behavioral, and intellectual disabilities in the offspring.

For references and more information, see the section on Pregnancy in the Alcoholic Beverages article.

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Coffee

What it does

General

  • Coffee is a complex mixture of chemicals. In addition to caffeine, coffee contains several phytochemicals that can influence human health.

Pregnancy-specific

  • Caffeine crosses the placenta and the fetus is exposed to caffeine via the umbilical cord and amniotic fluid.
  • Caffeine is metabolized more slowly in pregnant women, with a half-life of about 15 hours in pregnant women compared to about five hours in nonpregnant women.
What we know
  • Some, but not all, observational studies have associated high caffeine consumption with adverse effects during pregnancy, such as an increased risk of miscarriage and delivering a low-birth-weight baby.
  • Women who are pregnant or planning to become pregnant should limit caffeine consumption to less than 300 milligrams (mg)/day.
Table 4.  Common Sources of Caffeine
Food and Beverages
Caffeine Content (milligrams)*
Brewed coffee, 8 fluid ounces 96
Instant coffee, 1 teaspoon powder 31
Green tea, brewed from bag 44
Cola, 12 fluid ounces 33
Dark chocolate, 1 ounce 24
*Caffeine content can vary among commercial products. Search the USDA Nutrient Database for the caffeine content of a specific food or beverage.
HIGHLIGHT
  • Compounds in coffee can bind nonheme iron and inhibit its absorption.
  • In general, dietary supplements should not be consumed with coffee.

For references and more information, see the section on Health Risks of Pregnancy in the Coffee article.

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This content was underwritten, in part, by a grant from Bayer Consumer Care AG, Basel, Switzerland.