Chapter 4 Nutrition During Pregnancy

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Chapter 4Nutrition During Pregnancy
Nutrition Through the Life Cycle Judith E. Brown
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Introduction

• Topics covered include
• Status of pregnancy outcome
• Reducing infant mortality and morbidity
• Physiology of pregnancy
• Embryonic fetal growth and developmen
• Pregnancy weight gain
• Nutrition and course/outcome of pregnancy
• Nutrient needs during pregnancy

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Introduction

• Topics covered include
• Exercise and Pregnancy
• Food Safety issues during pregnancy
• Common Health Problems during pregnancy

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Time-related Terms Before, During, and After
Pregnancy
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The Status of Pregnancy Outcomes

• Infant mortality
• Reflects general health status of a population
• Decreases in mortality related to improvements in
  social circumstances, safe nutritious food
  supply, infectious disease control

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Natality Statistics Rates, Definitions, and
Trends in the Rates in the United States
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Differences by Race

• http//www.cdc.gov/nchs/data/databriefs/db09.htm

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Chronology of Events Related to Declines in
Infant Mortality in the United States
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Low Birthweight, Preterm Delivery, and Infant
Mortality

• Low birth weight or preterm infants at high risk
  of dying in 1st year of life
• 8.2 of births are LBW yet comprise 66 of infant
  deaths
• 12.7 are born preterm yet account for high
  incidence of infant deaths

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Reducing Infant Mortality and Morbidity

• Improve birth weight of newborns
• Desirable birth weight 3500-4500 g (7 lb. 12
  oz.-10 lb.)
• Infants born with desirable wt are less likely to
  develop
• Heart and Lung diseases
• Diabetes
• Hypertension

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Health Objectives for 2010 for the Nation
Related to Pregnant Women and Infants

• The Health Objectives for 2010 in relation to
  pregnant women and infants focus on
• The reduction of low birth weight,
• Preterm delivery
• Infant mortality
• A number of the objectives are related to
  nutrition

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Health Objectives for 2010 for the Nation
Related to Pregnant Women and Infants

• Nutrition related objectives
• Reduce anemia in pregnant females
• Reduce incidence of spina bifida
• Increase abstinence form alcohol use and reduce
  the incidence of fetal alcohol syndrome
• Increase appropriate weight gain during pregnancy

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Physiology of Pregnancy

• Key terms
• Gestational age
• Assessed from date of conception
• Average pregnancy is 38 weeks
• Menstrual age
• Assessed from onset of last menstrual period
• Average pregnancy is 40 weeks

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Maternal Physiology

• Changes in maternal body composition functions
  occur in specific sequence

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Normal Physiological Changes during Pregnancy

• Two phases of changes
• Maternal anabolic changes
• Takes place in the 1st half of pregnancy
• Maternal catabolic changes
• Takes place in the 2nd half of pregnancy

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Maternal Anabolic and Catabolic Phases of
Pregnancy
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Body Water Changes

• Body water
• Increases from 7 L to 10 L
• Results from increased blood and body tissues
  extracellular volume amniotic fluid
• Edema
• Swelling due to accumulation of extracelluar fluid

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Key Placental Hormones and Examples of their Roles
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Maternal Nutrient Metabolism

• Changes can be seen in the first few weeks after
  conception.
• Ensures that nutrients will be available to the
  fetus when needed.

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Carbohydrate Metabolism

• Glucose is preferred fuel for fetus
• Diabetogenic effect of pregnancy results from
  maternal insulin resistance

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Carbohydrate Metabolism

• Early pregnancy
• High estrogen progesterone stimulate insulin
  which increases glucose? glycogen fat
• Late pregnancy
• Human chorionic somatotropin (hCS) prolactin
  inhibit conversion of glucose to glycogen fat

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Protein Metabolism

• About 925 g of protein accumulate during
  pregnancy
• Protein amino acids conserved during pregnancy
• No evidence the body stores protein early in
  pregnancy
• Needs must be met by mothers intake of protein

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Fat Metabolism

• Fat stores
• Accumulate in first half of pregnancy
• Enhanced fat mobilization in last half
• Blood lipid levels increase
• Increased cholesterol is substrate for steroid
  hormone synthesis

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Mineral Metabolism

• Calcium
• Increased bone turnover reformation
• Sodium
• Accumulation in mother, placenta, fetus
• Restriction of sodium potentially harmful

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The Placenta

• Functions
• Hormone enzyme production
• Nutrient gas exchange
• Remove waste from fetus
• Structure
• Double lining of cells separating maternal
  fetal blood

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Structure of the Placenta
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The Placenta

• Nutrient Transfer
• Factors that affect the transfer
• Size and charge of molecules
• Small molecules pass through most easily
• Lipid solubility of particles
• Concentration of nutrients in maternal and fetal
  blood

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The Placenta

• Nutrient Transfer
• The fetus is not a parasite
• Nutrients first used for maternal needs, then for
  placenta last for fetal needed
• The fetus is harmed more than the mother by poor
  maternal nutrition

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Embryonic and Fetal Growth and Development

• Growth and Development
• Is at the highest level during the 9 months of
  gestation
• If rate gain continued at this level, at 1 year
  of age the infant would be 160 lbs.
• Table 4.12 provides an overview of embryonic and
  fetal development during pregnancy

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Critical Periods of Growth and Development

• Differentiation
• Cellular acquisition of one or more
  characteristics or functions different from that
  of the original cell
• Critical Periods
• Preprogrammed time periods during embryonic
  fetal development when specific cells, organs
  tissues are formed integrated or functional
  levels established

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Critical Periods of Growth and Development

• Four periods of growth development
• 1) Hyperplasia(? cell multiplication)
• 2) Hyperplasia hypertrophy
• 3) Hypertrophy(? cell growth)
• 4) Maturation (stabilization of cell number
  size)

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Fetal Body Composition
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Variation in Fetal Growth

• Variations linked to
• Energy, nutrient, oxygen availability
• Genetically programmed growth development
• Insulin-like growth factor (IGF-1) is main fetal
  growth stimulator

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Newborn Weight Classifications

• Terms to describe newborn size
• SGA (small for gestational age)
• dSGA (disproportionately small for gestational
  age)
• pSGA (proportionately small for gestational age)
• LGA (large for gestational age)
• Ponderal Index (similar to BMI)
• Calulated by wt in g divided by cube of lt times
  100
• PI for normal wt 23-25

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Nutrition, Miscarriages and Preterm Delivery

• Miscarriages
• Thought to be caused by genetic, uterine, or
  hormonal abnormalities
• Preterm Delivery
• Infants born preterm are at risk for death,
  neurological problems, congenital malformations,
  chronic health problems

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Fetal-Origins Hypothesis of Later Disease Risk

• Theory that exposures to adverse nutritional
  other conditions during critical or sensitive
  periods of growth development can permanently
  affect body structures functions
• Changes may predispose individuals to CVD, type 2
  diabetes, hypertension, other disorders in
  later life

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The Fetal-Origins Hypothesis

• Mechanisms underlying the fetal origins
  hypothesis
• Influenced by genes
• Also influenced by environmental exposure (in
  utero)
• AKA developmental plasticity
• Concept that the development can be modified by
  particular environmental conditions experienced
  by a fetus or infant

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The Fetal-Origins Hypothesis

• Environmental Exposures
• Modify development
• Epigenetic mechanisms
• Epigenetics (epiover, above)
• Biological mechanisms that change gene function
  without changing the structure of DNA.
  Epigenetic mechanisms are affected by
  environmental factors.

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The Fetal-Origins Hypothesis

• Nutrition programming
• Fetal exposure to certain levels of energy
  nutrients modify function of genes in ways that
  affect metabolism development of diseases in
  later life
• Limitations of the fetal-origins hypothesis
• Unanswered questions
• What levels are related to changes?
• What exposures?

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Pregnancy Weight Gain

• Weight gain during pregnancy is related to the
  weight and health status of the newborn infant
• Recommendations for weight gain during pregnancy
  is found in Table 4.17
• Recommendations for weight gain are influenced by
  the pre-pregnancy status of the mother

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Pregnancy Weight Gain Recommendations
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Rate of Pregnancy Weight Gain

• 2-5 pounds in first trimester
• Gradual consistent gains thereafter

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The Institute of Medicines Prenatal Weight-gain
Graph
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Composition of Weight Gain

• The fetus is only about 1/3 of the total weight
  gain
• The balance of the weight gain is related to body
  fat changes, placenta, amniotic fluid, increase
  of extracellular fluids, and blood supply of the
  mother

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Postpartum Weight Retention

• Much concern over pregnancy weight gain and
  long-term obesity
• 15 pounds lost at delivery
• Wt loss difficult in women who gained gt45 pounds
  or with low activity levels
• Women with recommended wt gain in pregnancy are
  2 pounds heavier at 1 yr postpartum
• Lactating women lose slightly more

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Nutrition and the Course and Outcome of Pregnancy

• Famine and pregnancy outcome
• The Dutch Hungerwinter, 1943-1944
• Decline in pregnancy rates
• Lower birth weights
• The siege of Leningrad, 1942
• Increase in infertility low birth weights
• Infant death rates increased
• Food shortages in Japan
• Similar to the outcomes found in Holland and
  Leningrad above

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Nutrition and the Course and Outcome of Pregnancy

• Contemporary prenatal nutrition research results
• Good nutritional status maintained before and
  throughout pregnancy decreases the risk of birth
  defects, suboptimal fetal growth and development,
  and chronic health problems later in life.

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Nutrient Needs During Pregnancy

• Nutrient needs vary during the course of the
  pregnancy
• Overall, nutrient needs can be met with well
  balanced, adequate and healthful diets consisting
  of basic foods

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Nutrient Needs During Pregnancy

• Energy requirements in pregnancy
• 300 additional cal/d
• 340/d in 2nd trimester 452/d in 3rd trimester
• Assessment of caloric intake
• Most easily assessed by pregnancy weight gain
• As long as there is no noticeable edema

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Carbohydrates, Artificial Sweeteners and Alcohol

• Carbohydrate intake (50-65)
• Basic foods such as
• vegetables, fruits, and whole grains with fibers
  best choice
• Artificial sweeteners
• No scientific evidence of harm
• Alcohol ingestion
• Strongly advised to avoid during pregnancy

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Protein

• Protein requirements
• 25 g/day or 71 g
• Average intake of typical female 78 g

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The Need for Fat

• Pregnant women consume 33 of total calories
  from fat
• Fat consumed in food is used as an energy source
  for fetal growth and development
• Fat serves as a source of fat-soluble vitamins
• Fat provides essential fatty acids

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Maternal Intake of Omega-3 Fatty Acids and
Pregnancy Outcome

• Adequate EPA DHA during pregnancy lactation
  linked to higher intelligence, better vision
  more mature CNS
• Dietary intake recommendations for EPA DHA
• Do not exceed 3 grams per day

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Other Nutrient Needs

• The need for water during pregnancy
• Met by increased levels of thirst
• Average consumption 9 cups fluid per day
• Recommend water, diluted fruit juice, iced tea,
  and other unsweetened beverages

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Other Nutrient Needs

• Folate and pregnancy outcome
• Folate background
• Known to be associated with anemia and reduced
  fetal growth
• Folate requirements ? - extensive organ and
  tissue growth
• Functions of folate
• Metabolic reactions
• Deficiencies lead to abnormal cell division and
  tissue formation

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Other Nutrient Needs

• Folate and pregnancy outcome
• Folate and congenital abnormalities
• NTDs Neural Tube Defects
• Malformations of the spinal cord and brain
• Three major types
• Spina bifida
• Anencephaly
• Encephalocele

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Other Nutrient Needs

• Folate and pregnancy outcome
• Folate status of women in the United States
• Have improved with fortified cereals and
  supplements
• Recommended intake of folate
• 600 mcg DFE (dietary folate equivalents)

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Other Nutrient Needs

• Dietary sources of folate
• Fruits, vegetables, whole grains

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A Newborn Child with Spina Bifida
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Other Nutrient Concerns

• Vitamin A
• Needed for cell differentiation
• In U.S. more concern re toxicity
• Vitamin D
• Supports fetal growth
• Supports immune system
• Fluoride
• Teeth begin to develop
• Not recommended to supplement

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Other Nutrient Concerns

• Calcium requirements in pregnancy
• Needed for fetal skeletal mineralization and
  maintain maternal bones
• Calcium and release of lead from bones
• Low intakes of calcium are related to increased
  release of leadharmful to fetus
• Needs can be met with 3 cups of milk or
  calcium-fortified soymilk or other adequate
  sources of calcium.
• (See Table 1.14 in Chapter 1)

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Iron Status and the Course and Outcome of
Pregnancy

• Additional iron needs for pregnancy
• 300 mg for fetus placenta
• 250 mg lost at delivery
• 450 mg for increased RBC
• Iron-deficiency anemia in pregnancy
• Early pregnancy-risk of preterm delivery
• Late pregnancy-lower scores on intelligence,
  language, gross motor and attention tests

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Iron Status and the Course and Outcome of
Pregnancy

• Assessment of iron status
• Iron deficiency A condition marked by depleted
  iron stores with weakness, fatigue, short
  attention span, poor appetite, increased
  susceptibility to infection and irritability
• Iron deficiency anemia a condition marked by low
  hemoglobin with signs of iron deficiency plus
  paleness, exhaustion and rapid heart rate

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Iron Status and the Course and Outcome of
Pregnancy
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Iron Status and the Course and Outcome of
Pregnancy

• Pros Cons of Iron Supplementation
• Iron is absorbed better from supplements
  containing iron only than when mixed with other
  minerals
• Amount absorbed depends on the need and the
  amount of iron in the supplement
• Side effects-nausea, cramps, gas constipation

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Iron Status and the Course and Outcome of
Pregnancy

• Pros Cons of Iron Supplementation
• New concern free radicals in GI tract-gtcause
  inflammation mitochondrial damage to cells
• May interfere with zinc absorption

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Iron Status and the Course and Outcome of
Pregnancy

• Recommendations related to iron supplementation
  in pregnancy
• Supplement with 30-mg iron daily after the 12th
  week of pregnancy
• Recommended intake of iron during pregnancy
• Upper limit is set at 45 mg per day

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Other Mineral Concerns

• Iodine
• Required for thyroid function energy production
  and for fetal brain development
• Sodium
• Restriction not indicated in normal pregnancy or
  for control of edema or high blood pressure
• Plays a critical role in maintaining bodys water
  balance

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Bioactive Components of Food

• Bioactive food components are foods or dietary
  supplements other than those needed to meet basic
  human nutritional needs that are responsible for
  changes in health status
• Are not considered essential nutrients but
  influence health

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Caffeine Use in Pregnancy

• No apparent long-term consequences for children
  of coffee intake during pregnancy
• Generally concluded-intake of up to 4 cups of
  coffee per day is safe

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Healthy Diets for Pregnancy
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Healthy Diets for Pregnancy

• Effect of taste and smell changes during
  pregnancy on intake
• May lead to changes in taste and smell
• Pica may result
• Pica
• Eating disorder Eat non-food substances

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Healthy Diets for Pregnancy

• Assessment of dietary intake
• Cultural considerations
• Evaluation of
• Dietary intakes
• Weight status
• Biomarkers of nutrient status
• Vitamin mineral supplementation
• Herbal remedies

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Dietary Supplements During Pregnancy

• Multivitamin and Mineral Prenatal Supplements
• Nutrient needs should be met by a well-balanced
  diet
• Iron is considered to be the exception
• Recommended for inadequate diets, multifetal
  pregnancy, smokers, drinkers, vegans, or
  diagnosed nutrient deficiencies

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Herbs to Avoid in Pregnancy
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Exercise and Pregnancy Outcome

• No evidence that moderate or vigorous exercise
  undertaken by healthy women is harmful
• Exercise recommendation for pregnant women
• 3-5 times each week for 30 minutes at 60-70 VO2
  max

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Food Safety Issues during Pregnancy

• Foodborne illness
• Listeria monocytogenes
• Toxoplasma gondii
• Mercury contamination
• High levels in large, long-lived predatory fish
• Lower content in bottom feeders
• Avoid shark, swordfish, king mackerel and tile
  fish

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Common Health Problems during Pregnancy

• Nausea and vomiting
• Hyperemesis gravidarum
• Severe N/V during most of pregnancy
• Management of nausea and vomiting
• Separate liquid food intake
• Avoid odors and foods that trigger N/V
• Dietary supplements for the treatment of nausea
  and vomiting
• Vitamin B6, multivitamins, ginger

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Common Health Problems during Pregnancy

• Heartburn
• Management of heartburn
• Ingest small meals frequently
• Do not go to bed with a full stomach
• Avoid foods that make heartburn worse
• Constipation
• Prevention
• Consume dietary fiber
• Drink water along with the fiber
• Laxative pills are not recommended