Transcript Pregnancy and Lactation

Chapter 15
Pregnancy
& Lactation
Prior To Pregnancy
• Goals-essential to conception &
healthy infant development
–Achieve and maintain a healthy
body weight
–Choose an adequate and balanced
diet
–Be physically active
–Avoid harmful influences
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Fetal Growth & Development
• Ovum + sperm  zygote
• Zygote – the first 2weeks after fertilization
– Implantation
• Embryo – 2 to 8 weeks after conception
• Fetus – from 8 weeks after conception to
full-term
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Critical
Periods-
if cell division
and number
are limited
during a
critical period
full recovery is
not possible
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Copyright 2005 Wadsworth Group, a division of Thomson Learning
Critical Periods
• Neural tube defects
–Anencephaly-the neural tube fails
to close so the brain is either
missing or fails to develop
–Spina bifida-incomplete closure of
the spinal cord and its bony
encasement
• Folate supplementation reduces the
risk
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Weight Prior To Conception
• Increased medical risks if a woman is
under- or overweight prior to pregnancy
• Prepregnancy weight affects development
of healthy support tissues – placenta,
amniotic sac, etc.
• Prepregnancy weight affects infant
birthweight
– Infant birthweight is the most potent
predictor of infant’s future health &
survival
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Weight Prior To Conception
• Underweight
– Preterm
• Overweight and obesity
– Post term
– Cesarean section
– Dieting is dangerous because ketosis
from fasting/low-CHO
diets impairs fetal brain
development
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Weight Gain
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Weight Gain
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Weight Gain
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Nutrient Needs
Energy – Extra food energy needed
1. No additional allowance is provided
during the 1st trimester
2. During the 2nd & 3rd trimesters RDA +
350-450 kcals/day
3. More if teenager, underweight, very
active, or multiple gestation
Protein – RDA +25 grams/day (~70 gms);
usually not a problem since most
diets already exceed recommendation
Nutrient Needs
Vitamins – Folate & Vitamin B12 needed in
large amounts for rapid cell proliferation
Folate needed for increased red blood cells
and to help prevent neural tube defects
1. Recommendation increases from 400
micrograms/day during childbearing
years to 600 micrograms/day during
pregnancy usually from supplements
Vitamin B-12 – RDA during pregnancy is
2.6 mcg/day; supplements
recommended for vegans
Nutrient Needs
• Minerals needed for:
1. Bones & teeth – calcium, phosphorous,
magnesium & fluoride involved in
building the skeleton
2. Blood – iron necessary for 50%
increase in maternal blood volume and
accumulation of fetal iron stores
during the 3rd trimester
3. Protein synthesis- zinc vital for DNA &
RNA synthesis
Nutrient Needs
Calcium – 1200 mg/day recommended to
conserve maternal bone mass while
supplying fetal needs
Flouride – supplements not recommended
if water flouridated
Iron – increased need cannot be met by
diet or existing stores so supplements
(30 mg/day) recommended during 2nd &
3rd trimesters
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High-Risk Pregnancies
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High-Risk Pregnancies
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Food Assistance Programs
WIC Program – helps low income
pregnant women & their children (<5
years) obtain needed food and
nutrition education for growth &
development and to reduce the risks
of preterm or low-birth weight
infants
Maternal Health
Preexisting Diabetes or Gestational Diabetes –
high blood glucose can lead to fetal
(macrosomia) & delivery complications
1. Usually dx’d in 2nd or 3rd trimester by
glucose tolerance test; screening at 24-28
weeks gestation
2. Dietary control involves avoiding simple
sugars, eating small, frequent meals/snacks,
and preventing excessive weight gain
3. 1/3 of women will go on to develop diabetes
in future
Maternal Health
Preexisting Hypertension or Preeclampsia–
high blood pressure may be preexisting
condition or may be pregnancy-induced
signaling onset of preeclampsia (condition
characterized by high blood pressure,
generalized edema, & proteinuria)
1. Control involves good nutrition (esp.
calcium) & bedrest
Nutrition-Related Concerns
•
•
•
•
Nausea
Constipation and hemorrhoids
Heartburn
Food cravings and aversions- due to
hormone-induced changes in sensitivity to
taste and smell instead of reflecting true
physiological needs
• Nonfood cravings – laundry starch, clay,
soil, ice
– Pica is associated with iron deficiency
anemia
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Maternal Discomforts
Nausea/Morning Sickness – caused by
hormonal changes early in pregnancy
(increased levels of hCG)
• Ways to Alleviate
1. On waking, rise slowly
2. Eat dry toast or crackers in morning
3. Eat small, frequent low-fat meals
4. Avoid strong or offensive food odors
• Severe cases – hyperemsis gravidarum;
usually require rehydration &
hospitalization
Maternal Discomforts
Heartburn – as baby grows, pressure on
mother’s stomach increases causing reflux
• Ways to Alleviate
1. Eat small, frequent meals slowly
2. Drink liquids between meals
3. Avoid spicy or greasy foods
4. Avoid lying down for right after eating
and elevate the head while sleeping
Maternal Discomforts
Constipation – slower GI motility
• Ways to Alleviate
1. Increase fluid intake to8 glasses a day
2. Eat foods high in fiber (fruits,
vegetables, whole-grain cereals)
3. Exercise regularly
4 Use laxatives only as prescribed by a
physician; do not use mineral oil
because it interferes with the
absorption of fat-soluble vitamins
Practices Incompatible
with Pregnancy
1. Cigarette smoking – restricts blood
supply to fetus, impairing fetal nutrition
& increases risk of low birth weight and
SIDS infants
2. Caffeine – limit to 1 cup “coffee”/day
or may lower infant birthweight
3. Medicinal Drugs – prescription meds
only with M.D. approval due to risk of
birth defects
Practices Incompatible
with Pregnancy
4. Illicit drugs, such as cocaine or
marijuana, also pass through placenta
causing toxicity & central nervous
system damage
5. Herbal supplements
6. Vitamin/mineral megadoses are toxic
7. Sugar substitutes in moderation
8. Alcohol may cause fetal alcohol
syndrome (severe mental & physical
retardation) & interferes with transport
of nutrients across placenta
Fetal Alcohol Syndrome
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Lactation
• Mammary glandssecrete milk
• Prolactin – hormone
responsible for milk
production
• Oxytocin-hormone
that causes milk to
eject
• Let-down reflex
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Copyright 2005 Wadsworth Group, a division of Thomson Learning
Copyright 2005 Wadsworth Group, a division of Thomson Learning
Copyright 2005 Wadsworth Group, a division of Thomson Learning
Mother’s Nutrient Needs
During Lactation
• Energy Needs – additional 500
kcals/day needed to produce
~25 oz. milk/day provided by
food & fat reserves (stored energy)
1. Breastfeeding can facilitate
maternal weight loss
2. Avoid diets - <1200 kcals/day
compromises milk production
Mother’s Nutrient Needs
During Lactation
• Fluids - >2 qts./day to prevent
dehydration
• Prenatal vitamin supplements
routinely prescribed
- RDAs same or slightly higher for
most nutrients except iron until
menstruation resumes
Mother’s Nutrient Needs
During Lactation
• Recommendation for protein the
same as during pregnancy
• Vitamins & Minerals – supplements
generally recommended to replete
maternal stores; prolonged
inadequate intakes reduce the
quality of the milk
• Water – 3 L/day to prevent
dehydration
Lactation
• Certain foods, esp. with strong or spicy
flavors, are avoided only if baby seems
sensitive
• Caffeine may cause irritability & difficulty
sleeping
• Alcohol easily enters breast milk
• Smoking decreases milk production
• Medicinal Drugs – most are compatible but
need to check with physician for those
contraindicated
• Illicit Drugs – high doses delivered in
breast milk
Lactation
• Breastfeeding considered the “gold
standard” for infant feeding due to
immunologic, health & social benefits
• Contraindications – Communicable
diseases (TB, hepatitis, HIV, etc.)
and certain meds/drugs that
adversely affect infant
Energy & Nutrient Needs
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Nutrient Needs
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