Pregnancy
What is it?
Having a baby is one of the most nutritionally demanding events in a woman's life. Many things influence the success of a pregnancy and every choice a woman makes, from caffeine consumption to vitamin supplements, directly affects the health of her baby. Optimal nutrition is essential as soon as a woman starts thinking about getting pregnant; and avoiding cigarettes, alcohol and drugs is as important as eating a healthy diet.
Nutrition and pregnancy
Women who avoid known risks and eat well before, during and immediately after pregnancy tend to have larger, healthier babies and experience fewer complications. The quality and quantity of a woman's diet plays a vital role in beginning and maintaining the growth and development of her baby, in successful breastfeeding and in a smooth recovery after birth. Poor nutrition can result in low birth weight babies who may have impaired intelligence and a greater risk of disease both earlier and later in life.
Food requirements during pregnancy are similar to those which can be met by eating a normal well-balanced diet that contains a variety of nutrient- dense foods. However, some individual nutrient needs are higher and a pregnant woman should make sure to include plenty of foods high in these particular vitamins and minerals in her diet. All the vitamins and minerals are essential for development of a healthy baby; but getting adequate intakes of calcium, iron, folic acid, phosphorus, magnesium, vitamin B6 and zinc is particularly important. Many women do not consume adequate amounts of these nutrients in their daily diets.
Some nutrients that a baby needs come from limited stores in bones and tissues stockpiled before conception, but most come directly from the mother's diet. Calorie needs increase by about 15 per cent, but the need for some nutrients may double. Eating nutrient-dense foods is vitally important for a woman to get enough vitamins and minerals without putting on too much weight.
Pregnancy is a time of great change in a woman's body. Changes include the growth of placental tissues; the increase in blood volume; increase in cardiac output; accumulation of body water; changes in levels of estrogen, progesterone and other hormones; preparation of breast tissues for lactation; and changes in lung, kidney, reproductive and urinary systems.
Pregnancy and weight gain
Pregnancy is not the time to try and lose weight. In total, it can take as many as 80 000 calories, in addition to those necessary for daily needs, to ensure the development of a healthy baby. After the first three months, most pregnant women need an additional 300 calories per day over and above their pre-pregnancy needs. If a woman does not consume enough calories, her body will use protein for energy instead of cell building.
The amount of weight a woman gains varies with age, height, weight, plans to breastfeed, and the number of babies she is carrying. For a woman of average height and weight, the suggested weight gain is 25 to 35 pounds (11 to 15 kg) or for a woman with twins 35 to 45 pounds (16 to 20 kg). An underweight woman might gain 28 to 40 pounds (13 to 18 kg) and an overweight woman 15 to 25 pounds (7 to 11 kg).
Aside from the weight increase due to the fetus, placenta and amniotic fluid, enlarged uterine and breast tissue, blood volume increases by about 50 per cent and accounts for 4 pounds (2 kg) of weight gain. Pregnant women also accumulate fluid, protein and fat stores, the amount of which varies between women. In the first three months, most women gain only 2 to 4 pounds (1 to 2 kg). After that, the average weight gain is nearly 1 pound (0.5 kg) per week. Exercise such as swimming or gentle yoga can be beneficial for pregnant women, and extra calories may be needed to offset the calorie expenditure through exercise.
Women who gain too much weight during pregnancy do not necessarily have bigger babies. The excess weight is in the form of fat which a woman may find more difficult to lose after the baby is born. Recent studies have shown that maternal obesity may increase the risk of neural tube defects such as spina bifida. A Body Mass Index of 29 or greater nearly doubles the risk of such birth defects. Seriously overweight women may consider losing some weight before trying to get pregnant. After the baby is born most women lose 12 to 14 pounds (5 to 7 kg). With good nutrition and normal activity, the extra weight can be lost within three months to a year.
Pregnancy and alcohol
Most experts advise pregnant women and those who are trying to get pregnant not to drink alcohol. Alcohol is harmful to the baby and impairs absorption, metabolism and utilization of essential vitamins and minerals. Around half of all women have the occasional drink when they are pregnant. Recent research has confirmed that women who drink alcohol before pregnancy but abstain in early pregnancy have babies no smaller than those who never drink alcohol. Women who do drink alcohol in early pregnancy have babies who weigh on average 6 ounces (150 g) less than babies born to those who don't drink. Chronic alcohol use during pregnancy leads to fetal alcohol syndrome, a disorder in which babies are severely damaged.
Pregnancy and essential nutrients
A pregnant woman's diet should consist of fruit, vegetables, grain products, milk and milk products, and protein foods such as legumes, lean meat and fish. Foods which are high in fat and sugar are not usually high in essential nutrients and should only be eaten in small amounts. Caffeine-containing drinks should be limited to one to two cups a day and artificial sweeteners should be avoided as they can contribute to nutrient deficiencies and may have adverse effects on the baby.
A pregnant woman should aim to eat:
- Three to four servings of dairy products a day, such as low fat milk, cheese, yogurt, cottage cheese, hot chocolate made with milk, cheese-topped pizza.
- Four or five servings of cereal grains, such as bread, bagels, muffins, crackers, cereal, rice, spaghetti or noodles.
- One to two servings of meat or protein foods, such as very lean red meat, poultry, fish and eggs.
- One to two servings of cooked dried beans and peas.
- Four to six servings of fruit and vegetables including at least two servings of dark leafy greens and red, yellow or orange vegetables. Two servings should be of vitaminC-rich foods such as an orange, broccoli, grapefruit and tomatoes.
Drinking six to eight glasses of water a day should provide adequate fluid and help prevent constipation, a common problem in pregnancy. Consuming plenty of fiber-rich foods is also helpful for this.
Pregnancy and protein
Protein is vitally important for the growth and development of the baby's tissues, the placenta, the amniotic fluid and the increase in the mother's blood volume. US recommendations are that pregnant women consume at least 60 g of protein daily, and in Australia experts recommend 51 g. The extra protein requirements of pregnancy can easily be obtained by eating an extra serving of lean meat, fish or legumes and drinking an extra glass of milk. However, some experts believe that intakes of dairy products should not increase dramatically as excessive amounts may cause allergies in the baby. If you do not consume dairy products, make sure you include other good sources of calcium in your diet. These include dark leafy greens and tofu. Making sure calorie intake is high enough ensures that protein is used for tissue synthesis rather than for meeting energy needs.
Experts recommend that a pregnant woman should eat two to four servings a day of protein-rich foods such as lean meat, fish, eggs, beans and tofu. One serving is 3½ ounces or 100 g. Most people eating Western diets routinely eat more protein than they need so most pregnant women may not have to consciously increase the amount of protein they eat. Some vegetarians and particularly vegans may be the exception to this, and may need to discuss their needs with a dietitian.
Vitamins, minerals and pregnancy
Optimal intake of all vitamins and minerals is essential for a healthy pregnancy. However, requirements for some of these increase considerably and supplements can be very useful in ensuring optimal intake.
Vitamin A
Adequate vitamin A is essential for a baby to develop normally as it plays a vital role in cell development and differentiation, ensuring that the changes which occur in the cells and tissues during fetal development take place normally. Vitamin A may also be involved in cell to cell communication, and deficiency can lead to birth defects. However, the recommended intake of vitamin A during pregnancy does not increase from pre-pregnancy needs, and women who are pregnant or trying to become pregnant should not take large amounts of vitamin A. Daily intakes above 3000 mcg RE (10 000 IU) increase the risks of birth defects such as malformation of the face, head, heart and nervous system.
In a 1995 study, researchers examined the links between vitamin A from food and supplements in almost 23 000 pregnant women. Women who consumed more than 4500 mcg RE (15 000 IU) of preformed vitamin A per day from food and supplements were over three times more likely to have a baby with a birth defect than women who consumed 1500 mcg RE (5000 IU) or less per day. For vitamin A from supplements alone, women who consumed more than 3000 mcg RE (10 000 IU) per day had almost five times the risk of birth defects than women who consumed less than 1500 mcg RE (5000 IU) per day. The risk may be greatest during the first seven weeks of pregnancy.1
However, a 1997 study conducted by researchers at the National Institute of Child Health and Human Development did not find a link between vitamin A consumption and birth defects. Their results showed that even in women consuming doses of vitamin A between 2400 mcg RE (8000 IU) and 7500 mcg RE (25 000 IU) the risk of having a baby with a birth defect was no higher than in women taking low doses.2
Many manufacturers have reduced the amount of vitamin A in multivitamin supplements or replaced it with beta carotene, which does not pose the same risks. Doses equal to or less than the RDA are not believed to be harmful, but women should not combine supplements with large amounts of pre-formed vitamin A-rich foods such as liver. Vitamin A acne cream has been known to cause birth deformities and is now available only on prescription.
B vitamins
Requirements for thiamin, riboflavin and niacin increase slightly with the increase in calorie intake. Increasing intakes of folate, vitamin B6 and vitamin B12 is particularly important.
Vitamin B6
Vitamin B6 needs increase in pregnancy, and low levels are associated with reduced growth and development of a baby's nervous system.3 Deficiency may also contribute to water retention, morning sickness, pre-eclampsia and birthing difficulties. It may also lead to diabetic and blood sugar problems in pregnancy.
Vitamin B6 supplements may be useful in treating nausea and vomiting during pregnancy. In a 72-hour study, researchers at the University of Iowa gave 25 mg of vitamin B6 every eight hours to 31 patients, while 28 patients received placebo. At the completion of therapy, only eight of 31 patients in the vitamin B6 group had any vomiting, compared with 15 of 28 patients in the placebo group.4
Folate
Optimal folate intake is essential for the development of a healthy baby. A
B group vitamin, folate is essential for the processes of DNA synthesis, increased blood volume, cell division and the development of healthy tissues; all of which occur very rapidly during pregnancy. Adequate folate is essential for normal birth weight and nerve development in newborn babies.
Folate deficiency can lead to defects of the brain and spine which are known as neural tube defects. These include spina bifida (open spine) and anencephaly, in which a major part of the brain and skull fails to develop. Neural tube defects are the second leading cause of death from birth defects in the USA, and even mild folate deficiency increases the risk of low birth weight, poor growth and spontaneous abortion.
Making sure folate levels are adequate is vital for any woman who might become pregnant as the high risk period for birth defects is around one month before conception until around one month after. Many women are unaware that they are pregnant during this time. The risk of neural tube defects in the US is around one per 1000 pregnancies, and around 50 per cent of neural tube defects may be preventable by increasing folate intakes.
It is now recommended that a woman who is pregnant or who is planning to become pregnant should consume at least 600 mcg of folic acid per day, up from an RDA of 400 mcg for a nonpregnant women. This folic acid can be obtained from foods such as leafy green vegetables, asparagus, liver, whole grain foods and eggs, or from supplements. In an effort to boost folate intake and help to reduce the occurrence of neural tube defects, cereal products are now fortified with folic acid. However, most doctors recommend folic acid supplements to women who may become pregnant. In fact, it seems that the levels of folate necessary to prevent neural tube defects are more easily derived from fortified foods or supplements than from natural food sources alone. Many experts recommend folic acid supplements and a diet rich in folates for women who are hoping to become pregnant.
In a 1996 study, Irish researchers compared the effectiveness of supplements, fortified foods and nonfortified foods in raising folic acid levels. Sixty-two women were randomly assigned to one of the following five groups: 400 mcg per day of folic acid as a supplement; an additional 400 mcg per day from folic-acid-fortified foods; an additional 400 mcg per day from nonfortified foods; dietary advice, and a control group. The results showed that red blood cell folate concentrations increased significantly only in the groups taking folic acid supplements or food fortified with folic acid. The researchers concluded that advice to women to consume folate-rich foods as the only way to boost folate levels is misleading.5
A trial of the effects of vitamin supplements containing folate on the incidence of neural tube defects involving over 4700 women was carried out in Hungary. In the women who did not receive folic acid, there were six babies born with neural tube defects. In the group receiving the supplements, there were none.6 In an editorial in the New England Journal of Medicine, Godfrey Oakley, MD of the Centers for Disease Control in Atlanta, commented that "anyone who chooses to counsel a woman to consume 400 mcg of food-derived folate rather than 400 mcg of supplemental folic acid will be recommending a strategy that has not been proved to prevent birth defects and that leads to lower blood folate concentrations."
Multiple pregnancies, long-term use of oral contraceptives, and anemia may increase folic acid requirements still further. Any woman who has had a baby with a neural tube defect should consult a doctor before trying to conceive as there may be a need for greater amounts of folic acid. Studies have shown that 4 mg of folic acid may reduce the recurrence of neural tube defects by more than 70 per cent in women who have had one baby with a neural tube defect. This extra amount is usually obtained by taking prescribed pure folic acid.
Some studies have shown that folic acid also protects against the most common form of congenital malformations, cleft lip and cleft palate. A recent US study found that it did not. Folic acid stores may take six months to return to normal levels after the birth of a baby.
Vitamin B12
Vitamin B12 requirements increase slightly in pregnant women as vitamin B12 works with folic acid in cell growth, and is essential to the normal development of the baby. Women who follow strict vegetarian or vegan diets may be at risk of deficiencies and should consult a dietitian. Deficiency may lead to infertility and stillbirth.
Vitamin C
Vitamin C recommended intakes increase in pregnancy from 60 mg to 70 mg per day in the US, and from 30 mg to 60 mg in Australia. Vitamin C has a vital role to play in tissue development, and also helps in the absorption of iron and the utilization of other essential minerals. Vitamin C levels may be low in women suffering from pre-eclampsia,7 a disorder which occurs in one in every 20 pregnant women. Symptoms include high blood pressure, headache, protein in the urine, blurred vision and anxiety. It can lead to eclampsia, a seizure disorder which can cause complications with pregnancy and even death. As an antioxidant, vitamin C may help to prevent the oxidative damage to fats which may worsen high blood pressure.
Pregnant women are usually advised not to take very high doses of vitamin C during pregnancy as this may lead to rebound scurvy after birth in babies no longer receiving large doses of vitamin C.
Vitamin D
Vitamin D is essential for the developing baby and aids in bone and tooth development via its role in calcium absorption. Although the new US government recommendations for Adequate Intake of vitamin D do not increase during pregnancy, supplements may be useful. The Australian NHMRC recommends that pregnant women receive reasonable exposure to sunlight and obtain 400 IU of vitamin D per day. The level of vitamin D in breast milk directly reflects maternal intake, and a severe vitamin D deficiency may lead to rickets in a developing baby. Deficiency is more of a risk in colder climates where the mother has limited exposure to sunlight or avoids vitamin D-fortified milk and milk products. However, pregnant women should avoid large doses of vitamin D as they can be toxic for the developing infant.
Vitamin E
The daily requirement for vitamin E may increase from 8 mg alpha TE (12 IU) to 10 mg (15 IU) during pregnancy, although there is little research on the effects of marginal intakes. Lower vitamin E levels may contribute to high blood pressure and pre-eclampsia. Vitamin E deficiency causes a build-up of fats damaged by free radicals which can lead to constriction of blood vessels and therefore to high blood pressure.8 Severe vitamin E deficiency in infants can lead to anemia.
Vitamin K
Vitamin K injections are commonly used to reduce the risk of internal bleeding in newborn babies. In the early 1990s, researchers reported a possible increase in the risk of childhood cancers in children who were given vitamin K injections after birth. Subsequent studies suggest that the risk cannot be totally ruled out, but if it exists it is likely to be small. (See page 177 for more information.)
Because of the possibility of an increased risk of cancer, researchers have investigated alternatives to injection. Some research suggests that oral supplements in three doses of 1 to 2 mg, the first given at the first feeding, the second at two to four weeks and the third at eight weeks may be an acceptable alternative.9
Calcium
Adequate calcium intake is vital for a baby to develop healthy bones and teeth. A full term baby accumulates about 30 g of calcium in bone mass. A pregnant woman's diet should include three to four calcium-rich foods per day, including low fat milk and milk products, and dark green leafy vegetables. Many women do not get enough calcium in their diets and a pregnant woman will most likely need to consciously increase her intake. Adequate calcium is especially important for pregnant women aged under 25 as their bones are still increasing in density.
A 1998 Australian study found that the lead which accumulates over a
woman's lifetime in her bones leaches out into her blood during pregnancy and may pass to the baby, with potentially harmful effects.10 This is most often seen in the last six months when the fetus draws calcium from the mother for bone development. High intakes of calcium or calcium supplementation may increase blood calcium levels. This reduces the amount of calcium, and therefore lead, which the baby draws from a mother's bones. It is important to avoid lead-containing calcium supplements such as dolomite.
Pregnant women whose diets are deficient in calcium are also at risk of muscle cramps. When calcium levels drop below normal there is an increase in the sensitivity of the nerves which may cause muscles to go into spasm.
The effects of a mother's high calcium diet during pregnancy may also be passed on to her children who will be less likely to suffer from high blood pressure in the future. The results of a 1997 study suggest that women who take calcium supplements in pregnancy have children with lower blood pressures. Researchers measured the blood pressures of almost 600 children of women who had previously been involved in a double-blind trial of the effects of calcium on blood pressure during pregnancy. The results showed that, overall, systolic blood pressure was lower in the calcium group, particularly among overweight children.11
The new US RDAs for pregnant and breastfeeding women are no longer greater than those for nonpregnant women. This is partly based on recent studies which suggest that the ability to absorb and retain calcium improves during pregnancy and these changes are enough to meet the extra demands placed on a woman's body by her baby. In a study published in 1998, researchers studied calcium metabolism in 14 pregnant women from before conception to five months after their periods restarted. When the women were pregnant, the increased calcium needs were met by improved absorption; and then during the early breastfeeding period, calcium excretion decreased. Some calcium was drawn from bone but this was recovered after menstruation restarted, although not to pre-pregnancy levels.12
In studies done in 1997, researchers tested the effect of 1000 mg of calcium per day on bone density during pregnancy. They took measurements at enrollment and after three and six months. The results showed no effect of either lactation or calcium supplementation on bone density in the forearm, and also no effect of calcium supplementation on the calcium concentration in breast milk.13 However, the women involved in this study were all consuming adequate levels of calcium, and it is possible that women whose calcium intake is lower than 1300 mg per day may benefit from extra calcium or supplements.
Pre-eclampsia
Calcium supplements have been used to lower a woman's risk of pre-eclampsia as there is some evidence that abnormalities in calcium metabolism are involved in the disorder. Many pregnant women do not consume enough calcium to ensure optimal blood pressure regulation, and the results of several clinical trials have suggested that calcium supplements reduce the incidence of pre-eclampsia.14 A 1996 analysis of clinical trials which looked at the effects of calcium intake on pre-eclampsia and pregnancy outcomes in 2500 women found that those who consumed 1500 to 2000 mg of calcium supplements per day were 70 per cent less likely to suffer from high blood pressure in pregnancy.15
However, the largest study done to date suggests that supplements do not prevent pre-eclampsia. The study, which was published in 1997 in the New England Journal of Medicine, involved 4589 healthy, first-time mothers. Half of the subjects received 2000 mg of calcium per day and the other half received a placebo. The researchers then assessed the incidence of high blood pressure and protein excretion in the urine. No significant differences in the groups were found. Supplements did not reduce other complications associated with childbirth or increase the incidence of kidney stones.16 The results of this study still leave open the possibility that calcium supplements may be useful as the women included in the study were already consuming higher than average levels of calcium than is typical even before they took the supplements. Women at high risk of pre-eclampsia were also not included in the investigation.
In a 1995 study, researchers assessed the effect of calcium supplementation and drinking milk on pre-eclampsia in over 9000 pregnant women. Results showed that women who drank two glasses of milk per day had the lowest risk. The risk for those drinking one glass of milk per day was similarly low but the risk for those drinking less than one glass of milk per day was substantially higher. Women drinking three or more glasses of milk per day also showed increased risk, as did those drinking four or more glasses per day.17
Fluoride
Children whose mothers have diets sufficiently high in fluoride during pregnancy seem to have fewer cavities than children whose diets are lacking in fluoride. A baby's first teeth start forming in the first few months of pregnancy and the adult teeth in the last few months. Fluoride affects the strength and susceptibility to decay of these teeth. Excessive fluoride, however, may produce mottled teeth.
Iron
Iron requirements increase in pregnancy due to the increase in the mother's blood volume and the demands of the developing baby. In pregnancy, the mother transfers 500 to 1000 mg of iron to her growing baby, mostly during the last few months. The number of red blood cells in the mother's blood increases by 20 to 30 per cent. This increased demand can lead to iron deficiency if dietary intake does not increase substantially to meet it. A pregnant woman with an iron deficiency is more prone to infection after delivery, spontaneous abortion and premature delivery. Iron deficiency also increases the risk of low birth weight babies, stillbirth and infant death. Infants born of anemic mothers may also be at risk of anemia.
Recommended iron intakes for pregnant women increase from 15 mg to 30 mg per day in the USA, and from 16 mg to 36 mg in Australia. Most women cannot obtain enough iron from dietary sources alone, and the US National Academy of Sciences recommends that pregnant women take a supplement containing 30 mg of iron daily during the last six months of pregnancy. Supplements are particularly important for women with low iron stores. During the later stages of pregnancy, the ability of the body to absorb iron increases.
Good sources or iron include liver, red meats, dried fruits and leafy green vegetables. Vegetarians and vegans need to pay particular attention to their iron intakes as the iron from plant sources may not be as well-absorbed as that from meat.
Iron supplements can cause constipation or nausea which can be reduced by taking the supplements in several small doses with meals and by drinking plenty of water; at least six to eight glasses daily. Iron supplements may adversely affect zinc status, and pregnant women who are taking iron supplements should include zinc-rich foods in their diets.
Magnesium
Magnesium requirements increase in pregnancy as magnesium is involved in many essential bodily functions. Marginal magnesium deficiency is considered to be very common, (15 to 20 per cent of the population) and as physical and emotional stress also increases requirements, pregnant women may be particularly at risk.
Magnesium sulfate is routinely used in the USA to prevent convulsions in pre-eclampsia and to break down toxins in pre-term labor. A 1996 research review of trials of magnesium sulfate in the treatment of eclampsia and pre-eclampsia analyzed data from nine randomized trials involving 1743 women with eclampsia and 2390 with pre-eclampsia. The analysis showed that magnesium sulfate is effective in preventing the recurrence of seizures in eclampsia and in preventing them in pre-eclampsia.18
Researchers involved in a 1996 study reported in the Journal of the American Medical Association, found that administration of magnesium sulfate to women before delivery reduced the risk of cerebral palsy in very low birth weight babies.19
A recent Swedish study showed that magnesium may help reduce the pain and discomfort of night-time leg cramps suffered by up to one-third of pregnant women. The cramps may be caused by magnesium deficiency, and pregnant women tend to have lower blood magnesium levels than nonpregnant women.20
Sodium
Pregnant women may need to consume 2 to 3 g per day of sodium. This amount is best obtained from a varied diet of wholesome, minimally processed foods with no salt added during cooking. Dietary sodium restriction is used to control pregnancy-related high blood pressure. It does not seem to lead to any adverse effects on other minerals or the baby.
Zinc
Recommended zinc intakes increase from 12 mg to 15 mg in the USA and from 12 mg to 16 mg in Australia. Adequate zinc is necessary for normal growth, birth weight and completion of full term pregnancy.
Zinc deficiency in early pregnancy can lead to congenital birth defects, low birth weight, spontaneous abortion, premature delivery, mental retardation and behavior problems. Maternal zinc status may also be associated with ease of pregnancy and delivery. Reduced zinc intake in the mother can also lead to children at greater risk of infection due to suppressed immunity.
Many pregnant women do not consume enough dietary zinc and may need supplementation, but should be aware that excessive use of supplements during pregnancy may be harmful for the fetus. Zinc supplementation has been shown to improve birth weight and head circumference. In a 1995 study, researchers at the University of Alabama at Birmingham conducted a trial involving 580 African-American pregnant women with low blood plasma zinc levels. The women were either given 25 mg of zinc or a placebo. The results showed that in all the women, infants in the zinc supplement group had a significantly greater birth weight and head circumference than infants in the placebo group.21
Pregnancy and supplements
The US National Academy of Sciences recommends supplements for those women who are vegetarians, smoke cigarettes, drink alcohol or who are carrying twins. Supplementation should begin in the last six months and should be at the following levels:
- Iron - 30 mg
- Vitamin C - 10 mg
- Zinc - 15 mg
- Folic acid - 400 mcg
- Copper - 2 mg
- Vitamin B6 - 2 mg
- Calcium - 250 mcg
- Vitamin D - 5 mcg
Morning sickness
Morning sickness is common in the first three months of pregnancy. Eating crackers or dry cereal in bed 10 to 15 minutes before getting up, avoiding high fat or fried foods, and drinking liquids in between meals instead of with them, may be successful in alleviating sickness in some cases. Vitamin B6 may also be helpful, (See page 93 for more information.) and many women report successful results with ginger preparations.
Pregnancy and vegetarians
Vegetarian diets are healthy for pregnant women as long as they contain a variety of foods with enough calories and nutrients to meet the extra needs of pregnancy.
As well as consuming sufficient iron and calcium-rich foods, vegetarians must make sure to obtain adequate vitamin B12 from fortified breakfast cereals, soy milk or a B12 supplement. Vegans may need additional vitamin D supplements (10 mcg per day) and vitamin B12 (2 mcg per day). Vegan women who wish to breastfeed may consider taking calcium supplements if they cannot obtain enough calcium from vegetables and nuts.
Breastfeeding
Under normal circumstances, breastfeeding a baby is an important part of pregnancy. Breast milk contains the correct balance of nutrients and also leads to fewer illnesses in the first year of life. It enhances immune function and also offers protection from allergies; although these may develop when a breastfeeding mother's diet is high in cow's milk. Breastfeeding can also help a woman return to her pre-pregnancy weight; and oxytocin, a hormone released during breastfeeding, can help the uterus back to normal size and health.
Calorie requirements may be even greater while breastfeeding than during pregnancy and the mother's diet can affect the quality and quantity of breast milk. A well-balanced diet during breastfeeding is similar to that advisable during pregnancy. Water is the main constituent of mother's milk so an adequate fluid intake is essential. This should be at least eight glasses of water per day. A breastfeeding woman's diet should be high in milk and milk products, protein, whole grains, fruit and vegetables. Caffeine, cigarettes, alcohol and drugs should be avoided.
Vitamin A
The RDA for vitamin A for women who are breastfeeding increases from 800 mcg RE to 1300 mcg RE. This can be met by increasing the intake of beta carotene-rich foods.
Vitamin K
Babies who are formula-fed tend to have a lower risk of hemorrhage than those who are breastfed, as vitamin K levels are higher in formula. Maternal vitamin K supplements may help to reduce the risk of vitamin K deficiency in breastfeeding newborn babies. In a study published in 1997, researchers gave daily doses of 5 mg vitamin K to mothers. This increased the vitamin K content of breast milk to levels comparable with that in infant formula.22
Calcium
Recommended calcium intakes for breastfeeding women are no longer greater than those for women who are not breastfeeding. This is partly based on recent studies which suggest that changes in calcium metabolism and absorption during pregnancy and breastfeeding are enough to meet the extra demands placed on a woman's body by her baby. A 1998 British study suggests that bone mineral density changes seen during breastfeeding seems to be unrelated to dietary calcium intake.23
Iron
Iron is also very important for women who are breastfeeding, especially if they are recovering from blood loss during delivery or depletion of body stores during pregnancy. Breastfeeding causes needs to increase by around 0.5 to 1 mg per day.
Other vitamins and minerals
Other vitamins and minerals which are required in higher amounts by breastfeeding women include vitamin C, vitamin E, some B vitamins, magnesium, zinc and selenium.