Chapter 10- Nutrition During Pregnancy and Lactation

Protein needs during pregnancy

DRI for nonpregnant: 46 g/day DRI for pregnant 71 g/day A typical non-preg woman consumes 73d/d Physically active or a high-risk pregnant women may need additional protein.

Protein food sources

Eggs, milk, beef, poultry, fish, pork, cheese, soy products, and other animal products Incomplete proteins from plant sources (legumes and grains) contribute amino acids. Protein-rich foods also contribute nutrients such as calcium, iron, zinc, and fat-soluble vitamins.

Complications of Pregnancy

For the majority of pregnant women, gestation will progress without complication. However, for others, preexisting health conditions or health problems that develop during the pregnancy will present difficulties throughout gestation. One such example is hyperemesis gravidarum, discussed earlier in this chapter. Other issues may affect only the fetus, such as neural tube defects. Although there are a large number of conditions that may complicate pregnancy, the discussion here will focus on the more common conditions. Anemia Iron-deficiency anemia is the most common nutrient deficiency worldwide and is a risk factor for delivering low birth weight infants.57-58 Adverse pregnancy outcomes associated with maternal anemia include higher risk of cesarean delivery, blood transfusion, maternal death, preterm birth, and retinopathy of prematurity.57-59 Approximately 38.2% of pregnant women worldwide experience iron-deficiency anemia (Hb <110 g/dL), with the highest prevalence in (48.7%) in African regions.60 Anemia is more prevalent among poor women, many of whom live on marginal diets that lack iron-rich foods, but it is not restricted to lower socioeconomic groups. Improvement of adequate iron intake (through food and supplements) is necessary to avoid the long-term detrimental effects of iron deficiency on the fetus. As a result of the severe complications of iron-deficiency anemia, the World Health Organization currently recommends daily supplementation of 30 to 60 mg elemental iron for 3 consecutive months per year for menstruating women and adolescent girls where the prevalence of anemia is about 40%.61 For women who are pregnant and non-anemic, the World Health Organization recommends supplementation of 120 mg elemental iron and 2800 mg of folic acid once per week throughout pregnancy.62 Intrauterine Growth Restriction Women with high-risk pregnancies have an elevated risk of intrauterine growth restriction (IUGR). A fetus suffering from IUGR is at risk for fetal brain injury, neurologic disorders, stillbirth, preterm birth, low birth weight, and small for gestational age.63,64 Approximately 4% of mothers in developed countries and as many as 30% of mothers in developing countries suffer from IUGR.63 The primary cause of IUGR is placental insufficiency. Many factors contribute to IUGR, but low prepregnancy weight, inadequate weight gain during pregnancy, inadequate folate and iron status, and the use of cigarettes, alcohol, and other drugs are modifiable risk factors. Furthermore, infants who suffer from IUGR are at higher risk for the development of chronic diseases as adults, including cardiovascular disease and hypertension.64 Hypertensive Disorders of Pregnancy The cause of hypertension during pregnancy is unknown, but it is a leading cause of pregnancy-related deaths worldwide. The definition of hypertension is a blood pressure of ≥140 mm Hg systolic or ≥90 mm Hg diastolic. Recently, the American College of Cardiology/American Heart Association Taskforce on Clinical Practice Guidelines for Hypertension lowered the diagnostic values for hypertension to a blood pressure of ≥130 mm Hg systolic and ≥80 mm Hg.65 However, the newer guidelines exclude pregnancy. Hypertensive disorders of pregnancy include several classifications.66 • Chronic hypertension: Preexisting hypertension or hypertension that appears before 20 weeks' gestation or persists beyond 12 weeks after delivery. Affects approximately 1% to 5% of all pregnancies. • Gestational hypertension (pregnancy-induced hypertension): High blood pressure diagnosed after 20 weeks' gestation without proteinuria or other diagnostic criteria for preeclampsia. Blood pressure returns to normal within 12 weeks' postpartum. Affects 6% to 17% of all pregnancies. • Preeclampsia: Gestational hypertension with proteinuria (≥300 mg/d of protein in 24-hour urine collection) or end-organ dysfunction (e.g., thrombocytopenia, liver and/or renal impairment). Since 2013, proteinuria is not required for preeclampsia diagnosis. Affects 3% to 5% of all pregnancies. • Eclampsia: Preeclampsia with seizures occurring from no other known cause. Eclampsia is most common after 28 weeks' gestation with up to 44% of cases occurring in the postpartum period. • Preeclampsia superimposed on chronic hypertension: Preexisting hypertension with the development of proteinuria or end-organ dysfunction during gestation. Affects 20% to 25% of women with chronic hypertension. Hypertension is the silent disease because it has no symptoms. However, pregnant women should consult with their health care provider if they experience symptoms such as severe headaches, blurred vision, chest pain, nausea, or a sudden weight gain (i.e., edema) because this may indicate hypertension. Specific treatment varies according to individual severity and presentation67; however, in any case, optimal nutrition is important, and prompt medical attention is required. Salt restriction is inappropriate because it does not prevent preeclampsia or help to treat the symptoms. An overall healthy diet before and during pregnancy with a high intake of plant foods, antioxidants, and high fiber is thought to be helpful. Women with mild preexisting hypertension or gestational hypertension, without additional co-morbidities, are usually not at risk for poor pregnancy outcome.66 Complications from severe hypertensive and preeclampsia/eclampsia often require hospitalization. Advanced cases require induced labor. Preeclampsia is a disorder of the placenta with no known cure. Preeclampsia/eclampsia is associated with poor fetal outcomes such as maternal and fetal morbidity and mortality, IUGR, low birth weight, and preterm delivery.66 Thus, early and consistent prenatal care is imperative to identify symptoms early. Gestational Diabetes Gestational diabetes is glucose intolerance with onset occurring during pregnancy, and the definition intrauterine growth restriction (IUGR) a condition that occurs when a newborn weighs less than 10% of predicted fetal weight for gestational age. stillbirth the death of a fetus after the 20th week of pregnancy. applies regardless of whether treatment is medication (e.g., oral hypoglycemic agents, insulin) or only diet modification. Women diagnosed with diabetes during the first trimester (usually by fasting or random blood glucose test) are assumed to have had undiagnosed diabetes before becoming pregnant and are therefore diagnosed with overt diabetes and not gestational diabetes.68 The treatment for gestational diabetes follows a protocol similar to that for type 2 diabetes, with diet and exercise the first-line treatment. Prenatal clinics routinely screen pregnant women between 24 and 28 weeks' gestation with either a "One-Step" or a "Two-Step" oral glucose tolerance test for diagnosis (see Chapter 20 for details). Screening is particularly important for women who are at higher risk for the development of gestational diabetes, including those who are 30 years old or older and are overweight (i.e., BMI of ≥25 kg/m2) and who have a history of any of the following predisposing factors: • Previous history of gestational diabetes • Family history of diabetes • Ethnicity associated with a high incidence of diabetes (Asian, Hispanic, African Americans, and Native Americans) • Glucosuria • Obesity • Previous delivery of a large baby weighing 4.5 kg (10 lb) or more Women with gestational diabetes are at higher risk for caesarean delivery and fetal damage such as birth defects, stillbirth, macrosomia, and neonatal hypoglycemia. Additionally, these women are 20 times more likely to develop type 2 diabetes, 2.8 times more likely to develop ischemic heart disease, and twice as likely to develop hypertension later in life.69 Therefore, identifying and providing follow-up testing and treatment with a well-balanced diet, regular exercise, and medication (as needed) are important interventions. Preexisting Disease Preexisting diseases (e.g., cardiovascular diseases, hypertension, type 1 or type 2 diabetes, human immunodeficiency virus, eating disorders) can cause complications during pregnancy. Inborn errors of metabolism (e.g., phenylketonuria) and food allergies or intolerances (e.g., celiac disease, lactose intolerance) must also be taken into consideration and maintained under good control to mitigate any flare-ups or compromised nutrient intake/absorption. Pregnant women may have any combination of preexisting conditions. In each case, a team of specialists manages a woman's pregnancy in accordance with the principles of care related to pregnancy and the particular disease involved. See Chapters 18 through 23 for major nutrition-related diseases that require medical nutrition therapy.

General Concerns

Gastrointestinal Problems Nausea and Vomiting Nausea and vomiting affect approximately 50% to 80% of women during early pregnancy in the United States.30 This can be distressing and disruptive to daily life. For the majority of women experiencing nausea and vomiting, these will persist throughout the entire day. Although often called "morning sickness" (i.e., nausea and vomiting limited to the morning hours), only a small percentage of women experience nausea and vomiting that is limited to the morning.31 Nausea and vomiting are likely caused by hormonal adaptations to human chorionic gonadotropin (hCG) released from the placenta and elevated estradiol levels.31 Nausea and vomiting most frequently occur during the first trimester between 6 to 12 weeks and resolve by 20 weeks. For approximately 20% of women, nausea and vomiting continue past 20 weeks but usually resolve by 22 weeks of gestation.30 In most cases it is self-limiting and does not indicate further complication. To date, there is inadequate evidence to support the efficacy of any particular pharmacologic or nonpharmacologic intervention for the treatment of nausea and vomiting during pregnancy.30 Pregnant women often use alternative treatments (e.g., acupuncture, acupressure) for the relief of symptoms; however, these methods do not appear to be consistently effective for treating nausea and vomiting in this population. Some studies show improvements in symptoms with the use of ginger and vitamin B6, although findings are inconsistent and high-quality research is limited.30-33 Current guidelines from the American College of Obstetricians and Gynecologists recommend vitamin B6 (pyridoxine) alone or vitamin B6 plus doxylamine in combination for first-line pharmacotherapy in the treatment of nausea and vomiting associated with pregnancy.31 Although the data do not indicate any one treatment will be effective in all women, some dietary and lifestyle interventions may be beneficial. The following dietary actions may help with the relief of symptoms.33 • Avoid an empty stomach by eating small, frequent meals and snacks that are fairly dry and bland with low fat and low fiber. • Drink liquids between (rather than with) meals. • Avoid odors, foods, or supplements that trigger nausea. • Try ginger (125 to 250 mg) or vitamin B6 supplements (10 to 25 mg). If nausea and vomiting persist and become severe and prolonged, an evaluation for hyperemesis gravidarum is necessary. This condition frequently requires medical treatment. Approximately 0.3% to 3% of pregnant women develop hyperemesis gravidarum.33 Women who have experienced this condition with their first pregnancy are at a greater risk for recurrence during additional pregnancies.33 Hyperemesis gravidarum is the leading cause of hospitalization for pregnant women in their first trimester.33 Health care providers should closely monitor women with hyperemesis gravidarum for hydration, electrolyte balance, and appropriate weight gain. Compromised pregnancy outcome and fetal growth occur in pregnancies with persistent hyperemesis gravidarum that prevents adequate nutrition and weight gain. Prescription antiemetic medication may benefit some women in this situation (see the Drug-Nutrient Interaction box, "Antiemetic Medications"). Constipation Although it is usually a minor complaint, constipation may occur during the latter part of pregnancy because of the increasing pressure of the enlarging uterus and the muscle-relaxing effect of progesterone on the gastrointestinal tract, thereby reducing normal peristalsis. Helpful remedies include adequate exercise, increased fluid intake, and consumption of high-fiber foods such as whole grains, vegetables, dried fruits (especially prunes and figs), and other fruits and juices. Pregnant women should avoid artificial and herbal laxatives. Hemorrhoids Hemorrhoids are enlarged veins in the anus that often protrude through the anal sphincter, and they are most common during the latter part of pregnancy. The increased weight of the baby and the downward pressure that this weight produces can cause vein enlargement. Hemorrhoids may cause considerable discomfort, burning, and itching; they may even rupture and bleed under the pressure of a bowel movement, thereby causing the mother anxiety. Dietary management for hemorrhoids is the same as that for constipation. Sufficient rest during the latter part of the day may also help to relieve some of the downward pressure of the uterus on the lower intestine. Hemorrhoids resolve spontaneously after delivery in many women, in which case long-term treatment is not necessary. Heartburn Pregnant women sometimes have heartburn or a "full" feeling. Heartburn occurs especially after meals from the pressure of the enlarging uterus crowding the stomach. Gastric reflux may occur in the lower esophagus, thereby causing irritation and a burning sensation. The full feeling comes from general gastric pressure, the lack of normal space in the area, a large meal, or the formation of gas. Dividing the day's food intake into a series of small meals and avoiding large meals at any time usually help to relieve these issues. Wearing loose fitting clothing may also help with comfort.

Daily Food Plan

General Plan Ideally, a pregnant woman will have an individualized food plan established to meet her nutrition needs. This food plan should be a varied and balanced diet including all food groups designed to supply the essential nutrients (see Table 10.1). Alternative Food Patterns The food plan provided in Table 10.1 may be only a starting point for women with alternate food patterns. Such food patterns may occur among women with different ethnic backgrounds, belief systems, and lifestyles, thereby making individual diet counseling important. Specific nutrients (not specific foods) are obligatory for successful pregnancies. Eating a variety of foods provides these nutrients. Informed health care providers encourage pregnant women to use foods that meet both their personal and their nutrient needs. For example, vegans can meet their dietary protein needs using soy foods (e.g., tofu, soymilk, soy yogurt, soybeans) and complementary proteins (see Chapter 4 for additional information and resources that address planning a vegetarian diet). Basic Principles of Diet and Exercise Regardless the food pattern, two important principles govern the prenatal diet: (1) pregnant women should eat a sufficient quantity of high-quality, nutrient-dense food; and (2) pregnant women should eat regular meals and snacks and avoid fasting and skipping meals. In addition, pregnant women, even those sedentary before pregnancy, are encouraged to exercise. Historically, pregnant women were discouraged from exercising, but now women are encouraged to be physically active during pregnancy. There are numerous benefits to being active during pregnancy (Box 10.2). Pregnant women are encouraged to participate in at least 150 minutes of moderate-intensity aerobic activity spread throughout the week or 30 minutes of moderately intense exercise on most, if not all, days of the week (unless there is a medical reason that prohibits exercise).19

High-Risk Pregnancies

Identifying Risk Factors Pregnancy-related deaths claim 18 women out of every 100,000 live births in the U.S with the highest rates found in black women.34 Therefore, identifying risk factors and addressing them early are critical to the promotion of a healthy pregnancy (see the Clinical Applications box, "Nutrition-Related Risk Factors in Pregnancy" for common nutrition-related risk factors). To avoid the compounding results of poor nutrition during pregnancy, it is important to identify mothers who are at risk for complications as soon as possible. Health care professionals should not wait for clinical symptoms of poor nutrition to appear. The best approach is to identify poor food patterns and to prevent nutrition problems from emerging. Examples of inadequate dietary patterns for maternal and fetal nutrition are as follows: (1) insufficient food intake; (2) poor food selection; and (3) poor food distribution throughout the day. Teenage Pregnancy Teenage pregnancy rates in the United States are at a record low with an annual rate of 18.8 pregnancies for every 1000 girls between the ages of 15 and 19 years.35 Teen pregnancy is associated with a high risk for pregnancy complications and poor outcomes, with increased rates of low birth weight, preterm delivery, and infant mortality.35 The following problems may contribute to pregnancy complications with teens36: the physiologic demands of the pregnancy, which compromise the teenager's needs for her own unfinished growth and development; the psychosocial influences of a low income; inadequate diet; and experimentation with alcohol, smoking, and other drugs. Little or no access to appropriate prenatal care may also significantly contribute to a lack of support, including nutrition support, for the pregnancy. Early nutrition intervention is essential for positive pregnancy outcomes. Changes from inconsistent and often poor food patterns of teenagers may be difficult to achieve. Experienced and sensitive health care workers in teen clinics may provide supportive individual and group nutrition counseling for teen mothers. Recognizing Special Counseling Needs Every pregnant woman deserves personalized care and support during pregnancy. Women with risk factors such as those in the following discussion have distinct counseling needs. In each case, the clinician must work with the mother in a sensitive and supportive manner to help her develop a healthy food plan that is both practical and nourishing. Health care providers should identify harmful dietary practices (e.g., fad dieting, extreme macrobiotic diets, attempted weight loss) early to mitigate them. In addition to avoiding harmful practices, several topics require sensitive counseling, including those related to age and parity, poor lifestyle habits, and socioeconomic problems. Age and parity Pregnancies at either age extreme of the reproductive cycle carry special risks. Adolescent pregnancy has many emotional and nutrition-related risks. Sensitive counseling provides both helpful nutrition information and emotional support in addition to good prenatal care throughout pregnancy. Pregnant women who are 35 years old or older and are having their first child also require special attention. Pregnancy rates among women who are more than 35 years old continue to rise in the United States.37 These women are at a higher risk for obstetric and perinatal complications such as preeclampsia, gestational diabetes, and cesarean delivery.38 In addition, women with an extremely high parity rate (i.e., those who have had several pregnancies within a limited number of years) are at an increased risk for poor pregnancy outcomes39 and additional physical and economic pressures of child care. Obesity Obesity presents health concerns at any stage of life, including pregnancy. High prepregnancy maternal BMI as well as excessive gestational weight gain increases the risk for adiposity in the offspring and perhaps the complications associated with obesity later in life.40 Thus, individual and specific person-centered counseling for pregnant women is ideal to help improve overall pregnancy outcome.19 Alcohol Alcohol use during pregnancy can lead to fetal alcohol spectrum disorders (FASDs), of which fetal alcohol syndrome (FAS) is the most severe form (Figure 10.1). Fetal alcohol spectrum disorders comprise the leading causes of preventable mental retardation and birth defects in the United States. Despite health messages to avoid alcohol when pregnant, approximately 10% to 15% of women in North America consume alcohol during pregnancy and 3% binge drink.41 It is difficult to determine the exact prevalence of FAS; however, one study estimated that 2 per 1000 live births in the United States are affected by FAS.41 Alcohol is a potent and well-documented teratogen. FAS is 100% preventable by abstaining from alcohol during pregnancy. Nicotine An estimated 8.8% of pregnant women continue to smoke cigarettes during pregnancy.42 Maternal cigarette smoking or exposure to secondhand smoke (also known as environmental tobacco smoke) during pregnancy is associated with placental complications (placenta previa and abruption), preterm delivery, fetal growth restriction, fetal brain development, congenital abnormalities, and child psychiatric disorders.43-47 Maternal smoking is also the strongest modifiable risk factor for sudden infant death syndrome (SIDS).48 Pregnancy is the leading cause of smoking cessation. Women who stop smoking at the onset of pregnancy have similar pregnancy outcomes as nonsmokers, meaning that they are able to avoid smoking-related complications for their infant by abstaining from smoking and avoiding smoke exposure.49 See the Clinical Applications box, "Low Birth Weight Baby" for more information regarding risk factors for fetal growth restriction. Drugs Drug use, whether medicinal or recreational, presents problems for both the mother and the fetus, especially when it involves the use of illicit substances. Drugs cross the placenta and enter the fetal circulation, thereby creating a potential addiction in the unborn child. Globally, cocaine use and methamphetamine use are increasing in the general population.50 The United States has reached a national crisis with prescription opioid abuse in the general population.51 These drugs affect both the mother, fetus, and long-term health of the child. Maternal hypertension, placental abruption, preterm birth, cesarean section, mortality, and morbidity are highest with methamphetamine use followed by opioid and other illicit drugs. The effects of these drugs persist beyond pregnancy with impaired cognitive development and poor executive function occurring through adolescence.50 Neonatal abstinence syndrome (NAS) is a condition from which the infant suffers after birth because of the abrupt discontinuation of a drug chronically used throughout gestation. Substances that may result in NAS include opioids (heroin, methadone, buprenorphine, and prescription opioid medications), selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, methamphetamines, and inhalants.51 Dangers come from the drugs themselves, the use of contaminated needles, and the impurities that are contained in illicit substances. Self-medication with over-the-counter drugs also may present adverse effects. Pregnant women should always check the label for safety notices of use during pregnancy or speak with their doctor or pharmacist regarding medications. Medications made from vitamin A compounds (e.g., retinoids such as isotretinoin, prescribed for severe acne) have caused birth defects and spontaneous abortion of malformed fetuses by women who conceived during acne treatment.52 Thus, the use of this medication without contraception is contraindicated. Despite the known risks, health care providers still sometimes prescribe these medications to pregnant women, resulting in unfavorable birth outcomes.52 Caffeine Caffeine use is common during pregnancy. Caffeine crosses the placenta and enters fetal circulation. Studies on caffeine use and pregnancy risks have been controversial with conflicting results over the past several decades. The majority of studies support amounts of 300 mg/d or less of caffeine during pregnancy to decrease the risk for congenital malformations, growth restriction, preterm, or spontaneous abortion (miscarriage) associated with higher intakes of caffeine.53 The use of caffeine and safety during pregnancy is understandably difficult to study. Pica Pica is the craving for and the purposeful consumption of nonfood items (e.g., chalk, laundry starch, clay). Pica is more common in children, pregnant women, women from minority racial populations, those malnourished, and those of low socioeconomic status.54-56 Although the etiology is unknown, pica is significantly associated with iron-deficiency anemia as well as other contributing factors, such as poor zinc status, low calcium intake, hunger, and emotional stress.56 The practice of eating nonfood substances can introduce pathogens (e.g., bacteria, worms) and inhibit micronutrient absorption, thereby resulting in various nutrient deficiencies. Most clients do not readily report the practice of pica; therefore, practitioners should always ask patients directly about their consumption of any nonfood substance. Socioeconomic difficulties Pregnant women who live in low-income situations may benefit from special counseling. Poverty places pregnant women at greater health risk because they often lack resources for adequate food, medical care, and shelter. Registered dietitian nutritionists and social workers on the health care team can provide specialized counseling and referrals. Community resources include programs such as the Special Supplemental Nutrition Program for Women, Infants and Children, known as WIC, which has helped to improve the health and well-being of many pregnant and lactating women and their children in the United States. In addition to food vouchers, WIC provides anthropometric and iron status assessment and nutrition education counseling regarding the nutrition needs of both the mothers and their babies (see Chapter 13 for more details).

Key Micronutrient Needs

Pregnancy requires increased vitamins and minerals to meet the greater structural and metabolic requirements of gestation. The DRI tables are located in Appendix B. Although all nutrients are important for a successful pregnancy, this textbook will focus on only select micronutrients that pose a specific risk for deficiency during pregnancy. Minerals Many physiologic and metabolic changes take place during pregnancy. Contrary to popular beliefs, the mother must meet her nutrient needs before the placenta meets its nutrient needs and before the fetus meets its nutrient needs. Consequently, all nutrients are of great importance in the maternal diet. Teratogenic effects may result from a maternal diet that is deficient in many of the minerals covered in Chapter 8 (e.g., Kestan disease, goiter, cretinism, fetal growth restriction). This text will cover the most common mineral deficiency concerns in the United States. Table 10.1 Daily Food Plan for Pregnant Women a , b First Trimester Second Trimester Third Trimester 2200 kcal 2400 kcal 2600 kcal Grains c 7 ounces 8 ounces 9 ounces Vegetables d 3 cups 3 cups 3½ cups Fruits 2 cups 2 cups 2 cups Milk 3 cups 3 cups 3 cups Meat and beans 6 ounces 6½ ounces 6½ ounces Aim for at least this amount of whole grains per day 3½ ounces 4 ounces 4½ ounces Aim for This Much Weekly Dark green vegetables 2 cups 2 cups 2½ cups Red and orange vegetables 6 cups 6 cups 7 cups Dry beans and peas 2 cups 2 cups 2½ cups Starchy vegetables 6 cups 6 cups 7 cups Other vegetables 5 cups 5 cups 5½ cups Oils and Discretionary Calories Aim for this amount of oils per day 6 teaspoons 7 teaspoons 8 teaspoons Limit extras (extra fats and sugars) to this amount per day 266 calories 330 calories 362 calories a This particular food plan is based on the average needs of a pregnant woman who is 30 years old, who is 5 feet, 5 inches tall, whose prepregnancy weight was 125 pounds, and who is physically active between 30 and 60 minutes each day. Plans provided by the MyPlate.gov site are specific to each individual woman; however, this is an example for a woman of the described stature and activity level. b These plans are based on 2200-, 2400-, and 2600-calorie food-intake patterns. The recommended nutrient intake increases throughout the pregnancy to meet changing nutrient needs. c Make half of your grains whole. d Vary your veggies. From the Center for Nutrition Policy and Promotion. (n.d.). USDA's MyPlate. U.S. Department of Agriculture. Retrieved April 4, 2019, from www.choosemyplate.gov. Calcium A good supply of calcium—along with phosphorus, magnesium, and vitamin D—is essential for both maternal health and development of fetal bones and teeth. A diet that includes at least 3 cups of milk or milk substitute daily (e.g., calcium-fortified soy milk), calcium-fortified orange juice, generous amounts of green vegetables, and enriched or whole grains usually supplies enough calcium. During pregnancy, physiologic changes occur in the mother's absorption capacity to help meet the needs of some nutrients; for example, calcium absorption doubles during pregnancy.20 This enhanced bioavailability helps the mother meet her calcium needs as well as those of the growing fetus. However, if calcium intake is insufficient, the mother's bone releases calcium.20 Calcium supplements are appropriate for cases of poor maternal intake or pregnancies that involve more than one fetus. Because food sources of the two major minerals (i.e., calcium and phosphorus) are similar, a diet that is sufficient in calcium also provides enough phosphorus. Iron Iron is particularly important during pregnancy. Iron is essential for the increased hemoglobin synthesis that is required for the greater maternal blood volume as well as for the baby's prenatal storage of iron. The average intake of iron for women of childbearing age in the United States is 14.5 g/day.11 However, the current DRI for iron during pregnancy is 27 mg/day, which is significantly more than both a woman's nonpregnant DRI of 18 mg/day and the current average intake.5 Food contains only small amounts of iron, which is typically not in a readily absorbable form. Similar to calcium, there is an increased absorptive capacity for iron during pregnancy. However, the maternal diet alone rarely meets requirements. Consuming foods that are high in vitamin C in addition to dietary sources of iron enhances the body's ability to absorb and use iron with a low bioavailability (i.e., plant sources of iron). In addition, it is helpful to avoid foods that inhibit iron absorption (e.g., whole-grain cereals, unleavened whole-grain breads, legumes, tea, and coffee) within meals that are high in iron to enhance absorption. small for gestational age (SGA) infant is smaller than a sex-matched and gestational age-matched infant. Birth weight is below the 10th percentile. teratogenic causing a birth defect. Because the increased pregnancy requirement for iron is difficult to meet with the typical American diet, pregnant women often take a daily iron supplement. A standard prenatal vitamin contains the RDA for iron and is usually sufficient. Unless diagnosed with iron-deficiency anemia, pregnant women should take no more than the UL of 45 mg/d. Only pregnant women who are experiencing anemia should take a higher dose of iron because iron supplements appear to offer no benefit for women who are not deficient and increase the risk of gastrointestinal side effects. Although the U.S. Preventative Task Force did not find justification for routine iron supplementation or screening, they concluded that there was no harm in pregnant women taking an oral, low-dose (30 mg/day) supplement of iron such as that in a prenatal vitamin.21 In the United States, Mexican American and non-Hispanic black women have a disproportionate prevalence of iron-deficiency anemia, for which the standard treatment is an oral dose of 60 to 120 mg/day of iron.22 However, low socioeconomic status is associated with lower iron supplement use.23 These data combined suggest that encouragement for African-American, Mexican-American, and low-income women to consume adequate iron through diet and supplementation during pregnancy is needed to benefit both the mother and the fetus. As with most supplemental forms of nutrients, bioavailability is suboptimal compared with food sources; hence, the reinforcement of a balanced diet with ample iron is still important. See Table 8.5 for a list of foods that are high in iron. Vitamins The DRIs for pregnant women are slightly higher for most vitamins. As total energy intake increases, so do the nutrients contained in the foods consumed. Therefore, the selection of nutrient-dense foods generally provides the recommended intake for most vitamins. As with the mineral section, the discussion here is limited to those vitamins that are of specific concern during pregnancy related to inadequate dietary intake. See Chapter 7 for more information on the function of each vitamin. Folate Folate is important for both mother and fetus throughout pregnancy. Tetrahydrofolic acid (TH4) participates in DNA synthesis, cell division, and hemoglobin synthesis. It is particularly relevant during the early periconceptional period (i.e., from approximately 2 months before conception to week 6 of gestation) to ensure adequate nutrient availability in the endometrial lining of the uterus for embryonic tissue development. The neural tube forms during the critical period from 21 to 28 days' gestation, and it grows into the mature infant's spinal column and its network of nerves. A neural tube defect (NTD) occurs when the neural tube fails to form properly. Full closure of the neural tube requires sufficient folate, possibly because of its role in methylation reactions and/or nucleotide biosynthesis.24 Genetics and environment also play a role in the development of NTDs. Although folate intake alone does not guarantee a pregnancy will be NTD-free, there is enough evidence to support the use of folate supplements and/or food fortification to reduce the overall occurrence. As evidence, countries with mandatory folic acid fortification have lower NTD rates than countries with no or voluntary folic acid fortification policies.25 NHANES data revealed that 50% of women who received folic acid only from enriched cereal grain products did not meet folic acid recommendations.26 Thus, it is likely that a combination of foods high in folate, fortified foods, and folic acid supplements are necessary for women to meet folate recommendations to decrease the risk of NTDs. Spina bifida and anencephaly are the two most common forms of NTDs, defined as any malformation of the embryonic brain or spinal cord. Spina bifida occurs when the lower end of the neural tube fails to close (see Figure 7.7). As a result, the spinal cord and backbone do not develop properly. The severity of spina bifida varies in accordance with the size and location of the opening in the spine. Disability ranges from mild to severe, with limited movement and function. Anencephaly occurs when the upper end of the neural tube fails to close. In this case, the brain fails to develop or is entirely absent. Pregnancies affected by anencephaly usually end in miscarriages or death soon after delivery. The current DRIs recommend a daily folate intake of 600 mcg/day during pregnancy and 400 mcg/day for nonpregnant women during their childbearing years.3 Women who are unable to achieve such dietary recommendations by eating foods that are fortified with folate may do so with a dietary supplement. All enriched flour and grain products, as well as fortified cereals, contain a well-absorbable form of folic acid. Other natural sources of folate include liver, legumes (e.g., pinto beans, black beans, kidney beans), orange juice, asparagus, and broccoli (see Table 7.11 for additional food sources of folate). Vitamin D As was mentioned in Chapter 7, vitamin D deficiency is a common worldwide problem, including among pregnant women. Vitamin D deficiency during pregnancy may be associated with adverse outcomes for both the mother and the fetus, including miscarriage, preeclampsia, gestational diabetes, and preterm birth. However, research studies investigating the connection between vitamin D deficiency and such pregnancy complications are contradictory.27 The current DRIs recommend pregnant and lactating women consume 15 mcg/d (600 IU) of vitamin D to ensure the absorption and use of calcium and phosphorus for fetal bone growth.2 These needs can be met by the mother's intake of at least 3 cups of fortified milk (or milk substitute) in her daily food plan. Fortified milk contains 10 mcg (400 IU) of cholecalciferol (i.e., vitamin D) per quart. The mother's exposure to sunlight increases her endogenous synthesis of vitamin D as well. Lactose-intolerant women or vegetarians can obtain adequate vitamin D from fortified soymilk or rice milk products (see Table 7.2 for additional food sources). Choline Although not technically a vitamin, choline is an essential water-soluble nutrient often grouped with the B-complex vitamins because of its various functions. The body makes choline, but only in small amounts. Therefore, it is required in the diet. Choline has many important functions, including phospholipid synthesis, neurotransmitter synthesis (acetylcholine), lipid transport, homocysteine metabolism, and gene expression.28 Maternal choline intake plays an integral role in placental health, fetus neurodevelopment, and potential long-term cognitive effects (e.g., memory, attention span, and problem solving) through childhood.28 Further, because of its role in single carbon metabolism (i.e., DNA methylation), insufficient choline is associated with NTDs independent of folate status.28 The current AI for choline during pregnancy is 450 mg/d with the AI increasing to 550 mg/d during lactation. Unfortunately, few Americans meet the recommendations, including only 8% of pregnant women.29 This may be a function of inadequate knowledge regarding this important nutrient. One survey found that only 10% of health professionals and 6% of obstetricians and gynecologists knew about the importance of choline in pregnancy and lactation.29 Pregnant women should be encouraged to incorporate choline-rich foods in their diet to ensure adequate amounts to support long-term cognitive health of the child. See Table 10.2 for foods rich in choline. Registered dietitian nutritionists are an excellent resource for pregnant women who need help planning an individualized balanced diet.

Dietary Guidelines for Pregnancy and Lactation

• Healthy weight before pregnancy • Pregnant women to gain weight within guidelines. • Choose heme rich foods; additional iron sources; and enhancers of iron absorption, such as vitamin C-rich foods. • 400-800 mcg per day folic acid in addition to food forms • Adequate dietary intake of choline and iodine. • 8 to 12 ounces low-mercury seafood per week. • Do not drink alcohol while pregnant.

Energy increase during pregnancy

+340 kcal/day during second trimester +452 kcal/day during the third trimester - equal to one small snack of banana, 8oz yogurt, and 1/8c mixed nuts. =approximately 15% to 20% above the energy needs of nonpregnant women.

Fat needs during pregnancy

-AMDR for fat remains the same during pregnancy (20% to 35% of total daily kilocalories) -The Adequate Intake (AI) for linoleic acid increases from 12 g/d to 13 g/d and alpha-linolenic acid increases from 1.1 g/d to 1.4 g/d.6. -Reasons for Increased ALA- converts to docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) within the body, which are necessary for fetal growth and development. -EPA is important for regulating inflammation, blood vessel dilation, and blood clotting. -DHA is a component of cell membranes and is important for fetal brain and retina development, especially during rapid brain growth of the third trimester.

Protein usage during pregnancy

-Development of the placenta placenta requires sufficient protein for its complete development -Growth of maternal tissues (uterine and breast) -Increased maternal blood volume plasma volume increases by 40% to 50% during pregnancy. -Amniotic fluid -Rapid fetal growth

Carbohydrate needs during pregnancy

-Fetus relies primarily on glucose as a fuel source -Acceptable Macronutrient Distribution Range (AMDR) of carbs is 45% to 65% total daily kilocalories, (same range as for nonpregnant adults.) -Minimum daily carbohydrate requirement increases from 130 g/day to 175 g/d to provide additional glucose to fuel both the maternal and fetal brain. -Pregnant women should focus on consuming whole grains, legumes, fruits, and vegetables as their carbohydrate sources.

EPA and DHA Recommendations during pregnancy

-Primary sources of EPA and DHA are fish and seafood. -Egg yolks and algae also contain DHA. -Currently no DRIs for EPA or DHA. -The Academy of Nutrition and Dietetics recommend adults consume 500 mg/d of EPA and DHA daily.

Reasons for Increased Calories during pregnancy

2nd & 3rd trimesters (1) to supply the metabolic workload fuel for mom and fetus (2) to spare protein for the added tissue-building requirements. Increased basal metabolic rate and need for more kilocalories due to cardio, resp, and renal workload.

Weight Gain During Pregnancy

Amount and Quality Appropriate weight gain is a positive reflection of good nutrition status and contributes to a successful pregnancy outcome. Table 10.3 provides an approximation of this weight distribution. The Institute of Medicine recommends setting weight gain goals that consider a woman's prepregnancy nutrition status and her BMI.20 Table 10.4 provides the recommended total gestational weight gain as well as the average rate of weight gain relative to prepregnancy BMI. It is important to note that women with a high BMI still need to gain weight to support growth and development of the fetus. Important considerations are the quantity and quality of weight gain as well as the foods consumed to achieve weight gain, which should consist of a nourishing, well-balanced diet. Inappropriate weight gain (i.e., too much or too little) is associated with adverse pregnancy outcomes. Based on a systematic review of weight gain in pregnancy, 23% of women gained weight below recommendations, which resulted in an increased risk of SGA and preterm infants. The study also found 47% of women gained more than the weight gain recommendations, which resulted in an increased risk of macrosomia and cesarean delivery.10 Table 10.2 Select Food Sources of Choline Item Quantity Amount (mg) Beef liver, pan fried 3 oz 356 Egg (with yolk) 1 large 147 Beef top round, braised 3 oz 117 Soybeans, roasted ½ cup 107 Chicken breast, roasted 3 oz 72 Beef, ground, 93% lean meat, broiled 3 oz 72 Fish, cod, Atlantic, cooked 3 oz 71 Mushrooms, shiitake, cooked ½ cup 58 Potatoes, red, backed, flesh and skin 1 large 57 Wheat germ, toasted 1 oz 51 Beans, kidney, canned ½ cup 45 Quinoa, cooked 1 cup 43 Milk, 1% fat 1 cup 43 Yogurt, vanilla, nonfat 1 cup 38 Brussels sprouts, boiled ½ cup 32 Broccoli, chopped, boiled, drained ½ cup 31 Data from the Nutrient Data Laboratory. (2019). USDA Food Composition Databases. U.S. Department of Agriculture, Agricultural Research Service. Retrieved May 8, 2019, from ndb.nal.usda.gov/ndb/. Severe caloric restriction during pregnancy is potentially harmful to the developing fetus and the mother. Such a restricted diet cannot supply all of the energy and nutrients that are essential to the growth process. Thus, it is inadvisable to attempt weight reduction during pregnancy. Special care for pregnant women who are suffering from eating disorders (e.g., anorexia nervosa, bulimia nervosa) is essential for the health of both the mother and the fetus. Rate of Weight Gain Approximately 1 to 2 kg (2 to 4 lb) is the average amount of weight gained during the first trimester of pregnancy. Thereafter, the rate of weight gain should be reflective of a woman's prepregnancy BMI. Women with a prepregnancy BMI between 18.5 and 24.9 kg/m2 generally gain approximately 0.4 kg (14 oz) per week during the remainder of the pregnancy. The rate of weight gain for underweight women should be slightly more than the average. Overweight and macrosomia an abnormally large baby. obese women should average a slower rate of weight gain (see Table 10.4). Table 10.3 Approximate Weight Gain Distribution During a Normal Pregnancy Product Weight (lb) Fetus 7.5 Placenta 1.5 Amniotic fluid 2 Uterus 2 Breast tissue 2 Blood volume increase 3 Maternal stores: fat, protein, water, and other nutrients 11 Total 29 Full-term pregnant woman. Reprinted from Lowdermilk, D. L., & Perry, S. E. (2012). Maternity & women's health care. (10th ed.). St. Louis: Mosby. It is important for health care providers to monitor unusual patterns of weight gain closely. For example, a sudden increase in weight after the 20th week of pregnancy may indicate abnormal edema and impending hypertension. Alternatively, an insufficient or low maternal weight gain is a predictor of SGA infants with increased risks for complications.

Baby Friendly Hospital Initiative

The World Health Organization and the United Nations Children's Fund launched the Baby-Friendly Hospital Initiative in 1991 to promote breastfeeding worldwide. The Baby-Friendly Hospital Initiative outlines the 10 steps for successful breastfeeding, found in Box 10.3. Almost all women who choose to breastfeed their infants can do so, provided they have the necessary information and support from their family, community, and health care system. Well-nourished mothers who exclusively breastfeed provide adequate nutrition to their infants, as well as other beneficial components (e.g., immunoglobulins, prebiotics).