although conclusions about caffeine’s effects on pregnancy are largely based on coffee intake, it is possible that other components of coffee are respon-sible for effects observed. Coffee is by far the largest contributor to caffeine intake in most people,193 and pregnant women consume on average 144 mg caffeine from coffee per day in pregnancy.194 (Table 2.5 in Chap-ter 2 provides a list of the caffeine content of beverages and foods.)
Despite the possibilities, evidence from well-controlled trials of caffeine or coffee intake and fetal growth restriction, malformations, preterm birth, and delivery complications does not support a relationship.195,196 No long-term consequences of coffee intake during pregnancy have been observed in children 7 years later. Children of women who drank coffee during pregnancy have been found to have similar levels of intellectual and neuromo-tor development when compared to children of non-coffee drinkers.196 Avoidance of caffeine and coffee during preg-nancy does not appear to improve pregpreg-nancy outcomes or infant birth weight.195 It is generally concluded that intake of up to 4 cups of coffee per day during pregnancy is safe.196
Healthy Diets
may, however, develop food preferences and aversions due to changes in the sense of taste and smell, and they may experi-ence pica.
Changes in the way certain foods taste, and the odor of foods and other substances, affect two out of three women during pregnancy. If asked to recall, many previously pregnant women could tell you which foods tasted really good to them, and which odors made them feel queasy to even think about. Increased preference for foods such as sweets, fruits, salty foods, and dairy products are common.197 The odors of meat being cooked, coffee, per-fume, cigarette smoke, and gasoline are common nasal offenders and may stimu-late episodes of nausea.198 The biological bases for such changes are not known, but they are suspected of being related to hor-monal changes of pregnancy.
Pica
“Pica permits the mind no rest until it is satisfied.”
F. W. Craig, 1935
Classified as an eating disorder, pica affects over half of pregnant women in some locations of the southern part of the United States. It is more common in African Americans than in other eth-nic groups, and it is common enough to be considered a normal behavior in some countries. Historically, one type of pica—geophagia—was thought to pro-vide women with additional minerals and to ease gastrointestinal upsets. The cause of pica remains a mystery.199
Nonfood items most commonly craved and consumed by pregnant women with pica include ice or freezer frost (pagophagia), laundry starch or cornstarch (amylophagia),
baking soda and powder, and clay or dirt (geophagia).
Women experiencing pica are more likely to be iron deficient than those who don’t, and iron-deficiency anemia is especially common among pregnant women who compulsively consume ice or freezer frost.200 It is Table 4.30 Recommended Dietary Allowances and Upper Limits
for pregnant and nonpregnant women aged 19–30 years*
Pregnant Nonpregnant Upper Limit (UL) Energy, kcal
2nd trimester 1350 2403 —
3rd trimester 1452
Protein, gm 71 46 —
Linoleic acid, g 13 12 —
Alpha-linolenic acid, g 1.4 1.1 —
Vitamin A, mcg 770 700 3000
Vitamin C, mg 85 75 2000
Vitamin D, mcga 5 5 50
Vitamin E, mg 15 15 1000c
Vitamin K, mcg 90 90 —
Thiamin, mg 1.4 1.1 —
Riboflavin, mg 1.4 1.1 —
Niacin, mg 18 14 35c
Vitamin B6 1.9 1.3 100
Folate, mcgb 600 400 1000c,d
Vitamin B12, mcg 2.6 2.4 —
Pantothenic acid, mcg 6 5 —
Biotin, mcg 30 30 —
Choline, g 450 425 3.5
Calcium, mg 1000 1000 2500
Chromium, mcg 30 25 —
Copper, mcg 1000 900 10,000
Fluoride, mg 3 3 10
Iodine, mcg 220 150 1100
Iron, mg 27 18 45
Magnesium, mg 350 310 350c
Manganese, mg 2 1.8 11
Molybdenum, mcg 50 45 2000
Phosphorus, mg 700 700 3500
Selenium, mcg 60 55 400
Zinc, mg 11 8 40
* DRIs for females ,19 and .30 years are listed inside the front covers of this book.
a 1 mcg 5 40 IU vitamin D; DRI applies in the absence of adequate sunlight.
b As Dietary Folate Equivalent (DFE). 1 DFE 5 1 mcg food folate 5 0.6 mcg folic acid from fortified food or supplement consumed with food 5 0.5 mcg of a supplement taken on an empty stomach.
c UL applies to intake from supplements or synthetic form only.
d Applies to intake of folic acid.
on the DRIs (Table 4.30). Nutrient intakes during preg-nancy should approximate those given in the DRI table, and food intake should correspond to the recommended types and quantity of food recommended in MyPyramid.
Effect of Taste and Smell Changes on Dietary Intake During Pregnancy
No inner voice directs women to consume foods that pro-vide needed nutrients during pregnancy. Pregnant women
Pica An eating disorder characterized by the compulsion to eat substances that are not food.
Geophagia Compulsive consumption of clay or dirt.
Pagophagia Compulsive consumption of ice or freezer frost.
Amylophagia Compulsive consumption of laundry starch or cornstarch.
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Assessment of Nutritional Status During Pregnancy
A comprehensive approach to nutrition assessment in pregnancy includes an evaluation of dietary intake, weight status, biomarkers of nutrient status, food prefer-ences and resources, previous pregnancy and health his-tory, and dietary supplement use.201 In this chapter we highlight two of these components: assessment of dietary intake and nutrition biomarkers.
Dietary Assessment During Pregnancy
Routine assessment of dietary practices is recommended for all pregnant women to determine the need for an improved diet or vitamin and mineral supplements.34 Di-etary assessment in pregnancy should cover usual diDi-etary intake, dietary supplement use, and weight-gain progress.
For best results, several days of accurately recorded, usual intake should be used for each assessment.
Several levels of dietary assessment can be under-taken. (Internet resources for dietary assessment are listed at the end of the chapter.) Which assessment level is best primarily depends on the skill level of the health profes-sional responsible for interpreting the results. Results of food-based assessments are rather straightforward to in-terpret, whereas computerized assessments of levels of nu-trient intake are more complex.
The MyPyramid food guide provides a good way to as-sess a typical diet during pregnancy. Table 4.31 presents this guide based on a caloric need of 2400, which is not unusual for pregnant women in the United States. Daily amounts not clear, however, whether iron deficiency leads to pica
or if pica leads to iron deficiency.
Pica does not appear to be related to newborn weight or preterm delivery. It can, however, complicate control of gestational diabetes if starch is eaten, and it has caused lead poisoning, intestinal obstruction, and parasitic infes-tation of the gastrointestinal tract.200 Women with amylo-phagia sometimes accept powdered milk as an alternative to laundry starch or cornstarch, and treating anemia often stops the craving for ice or freezer frost.
Cultural Considerations People tend to be attached to existing food preferences, many of which may have deep cultural roots. Dietary recommendations will differ for Native Alaskans accustomed to a diet based on wild game; for Cambodians, Vietnamese, and Somalis who may think no meal is complete without rice; and for lactose-intolerant individuals.
The belief that consumption of certain foods “marks”
the baby is common in many cultures. People may think, for example, that a woman who loves mangos and eats lots of them during pregnancy may have a baby born with a “mango-shaped” birthmark. Some cultures would hold that the baby will also have learned to love mangos be-cause its mother ate them often while pregnant.
Dietary recommendations that are not consistent with a person’s usual dietary practices and beliefs, or that are not viewed as acceptable or even preferred by the woman, are least likely to be effective. For best results, dietary adjustments recommended for each individual pregnant woman should take into account her usual practices and preferences.
a The MyPyramid Plan for Moms shown here is for a 32-year-old female, 5 feet 6 inches tall, 130 pounds before pregnancy, who is physically active for 30 to 60 minutes a day. She is in her second trimester of pregnancy.
Table 4.31 MyPyramid Food Guide for pregnant womena
Food Group Ounces/Cups Recommended per Day Examples of Equivalent Measures Grains 8 oz (includes 4 oz whole grain products) • 1 slice bread 5 1 oz
1 c cold cereal
• 5 1 oz
1 c cooked rice, pasta, or cereal
• 5 2 oz
Vegetables 3 c (includes dark green and orange vegetables) • 2 c tossed salad 5 1 c
Fruits 2 c • 1 c fruit juice 5 1 c
Milk 3 c • 1⁄3 c shredded cheese 5 1 c
2 slices American cheese
• 5 1 c
1
• 1⁄2 oz hard cheese 5 1 c 1
• 1⁄2 c ice cream 5 1 c
Meat and beans 61⁄2 oz • 1 small egg 5 1 oz
1 Tbsp peanut butter
• 5 1 oz
1⁄4
• c dried beans 5 1 oz
1⁄2
• oz nuts 5 1 oz
Oils 7 tsp • 1 Tbsp mayonnaise 5 21⁄2 tsp oil
1 Tbsp salad dressing
• 5 1 tsp oil
a The MyPyramid Plan for Moms shown here is for a 32-year-old female, 5 feet 6 inches tall, 130 pounds before pregnancy, who is physically active for 30 to 60 minutes a day. She is in her second trimester of pregnancy.
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recommended for each food group can be compared to that recorded by a pregnant woman and the results used to iden-tify the general quality of the diet. Table 4.32 shows how closely the example of a day’s diet based on MyPyramid recommendations matches recommended levels of nutri-ent intake for pregnancy. With the exception of vitamin E and iron (which are supplied in rather low amounts by the example diet), nutrient levels correspond to recommended intakes for pregnancy.
Computerized analysis, given accurate records and entry of dietary intake and a high-quality nutrient data-base, provides results useful for estimating the quantity of calories and nutrients consumed. Detailed knowledge of dietary intake is particularly useful for women at risk of nutrient inadequacies or excesses, and for women with conditions such as gestational diabetes, food intolerances, and multifetal pregnancy.
Nutrition Biomarker Assessment
Nutrition assessment of pregnant women usually includes laboratory tests of iron status, and will include tests to de-termine the status of other nutrients as indicated. Due to the normal physiological changes occurring during preg-nancy, such as hemodilution, that affect blood nutrient concentrations, assessment of nutrition biomarkers should
employ standards developed for pregnancy.202 Blood nu-trient concentrations change with time during pregnancy, so no one value per nutrient for all of pregnancy accu-rately reflects status.
Studies reporting reference values for nutrition biomar-kers during pregnancy are beginning to appear in the scien-tific literature. These values are shown in Table 4.33. The concentrations listed by week of gestation consists of values from the 2.5 percentile to the 97.5 percentile of the distri-bution of values within a sample of well-nourished women with healthy, uncomplicated pregnancies. These values are assumed to reflect normal ranges of nutrition biomarker concentrations during pregnancy. They are intended to assist clinicians in distinguishing between physiological changes and pathological states during pregnancy.202