chapter 16 - pregnancy, lactation, infants Flashcards
full-term gestation
gestational period lasting 38-42 weeks
pre-term
birth prior to 37 weeks gestation
LBW
low birth weight = under 5.5 lbs
small for gestational age
infants that weigh less than expected for their gestational age
gestation
begins when sperm & egg unite
embryonic & fetal development
zygote = conception to 2 weeks
embryo = 2 weeks to 8 weeks
fetus = 9 weeks to birth (period of very rapid development)
critical periods of development
limited windows of opportunity for a tissue or organ to develop
most of these are during the embryonic stage
zygote nourishment
nourishes itself by absorbing secretions from glands in the uterus
placenta formation
forms in uterus as the zygote develops into an embryo
umbilical cord provides connection from placenta to fetus
placenta function
placenta is a living organ that:
- synthesizes fatty acids, cholesterol, & glycogen for fetus
- produces hormones which direct nutrients to fetus, control fetal metabolism, & promote changes in mom’s body to support pregnancy
importance of nutrition in pregnancy
- ensures appropriate fetal growth
- improves likelihood of full-term development
- increases mental, physical, & physiological capabilities
calories’ effects on pregnancy
deficiency = slow growth, low birth weight
excess = delivery complications, high birth weight
energy needs during pregnancy
needs additional kcal & nutrients for:
- fetal & placental growth
- maternal stores
- increased maternal metabolism
energy requirements by trimester
1st trimester EER + 0 kcal
2nd trimester EER + 340 kcal
3rd trimester EER + 452 kcal
nutrients of concern
- protein
- EAAs
- zinc
- folate
- B12
- iron
folate deficiency risk in pregnancy
folate deficiency = neural tube defects
pregnancy weight gain
for underweight people: 28-40 lbs
for normal people: 25-35 lbs
for overweight people: 15-25 lbs
for obese people: 11-20 lbs
obese pregnancy risks for baby
increased risk of:
- birth defects (neural tube defects, oral clefts)
- being stillborn/dying first few weeks after birth
- having high birth weight
- childhood obesity
obese pregnancy risks for mom
increased risk of:
- high blood pressure
- gestational diabetes
- cesarean delivery
underweight pregnancy risks for baby
increased risk of:
- low birth weight
- premature birth
- lower nutrient stores
factors that complicate pregnancy outcomes
- young mom
- mom’s eating patterns (restriction, vegetarian/vegan, EDs)
- mom’s health (# of pregnancies, time between pregnancies, gestational diabetes)
pregnancy-induced hypertension risks
impairs delivery of oxygen & nutrients to fetus
can lead to preeclampsia (edema, headaches, blurred vision) & eclampsia (coma, death of mom & fetus)
gestational diabetes
occurs in 9% of pregnancies, more common in those with family history
increased risks:
- infant is too large
- infant has low glucose levels at birth
- obesity later in life for infant
- mom & baby develop T2DM later in life
sociocultural factors for inadequate diet in mom
limited income, limited education, lack of social support
nutrition-related physiological concerns in pregnancy
physical & hormonal changes can cause:
- heartburn
- constipation
- nausea & vomiting
- edema
foods to limit in pregnancy
- environmental contaminants (mercury in fish)
- foodborne pathogens
- caffeine (limit to 200mg/day = 2 cups coffee or 3 sodas)
- food additives
foods to completely avoid in pregnancy
- drugs & alcohol
- herbal teas
- smoking
FAS
fetal alcohol syndrome
- smaller-than-normal head circumference
- reduced size of eye opening
- thin upper lip
pregnancy & physical activity guidelines
physical activity carries minimal risks and benefits most pregnant women
to measure exertion, use perceived exertion (talk test) instead of HR
lactation
physiological process in female mammals where postpartum mom’s breast secretes milk
let-down reflex
suckling stimulates nerves in nipple/areola that travel to hypothalamus
brain releases oxytocin & prolactin
oxytocin stimulates lobules in breast to release milk, prolactin stimulates additional milk production
colostrum
thin, yellow, early (‘immature’) breast milk
less lactose & calories
colostrum contains
rich in protein, minerals, vit A
contains antibodies & immune system cells
lactobacillus bifidus factor
transitional milk
breast milk from a few days post-delivery to 1 week
contains more fat, lactose, water-soluble vitamins, and calories than colostrum
mature milk
replaces transitional milk, thin & watery
20 calories/oz
nutritionally complete for infant EXCEPT Vit D & iron
food needs during lactation
500 calories above pre-pregnancy requirements (300 of these calories come from food sources, 200 come from fat stores)
the 500 calories vary depending on BMI & length of breastfeeding
fluid needs during lactation
additional 32 oz of fluid each day
fluid = main component of breast milk
nutrient needs during lactation
iron needs decrease
insufficient calcium consumption = common
peak growth during infancy
this is the period when nutrient needs per unit of body weight are the highest
baby = double their birth weight by 2-6 months, triple their birth weight by 1 year old
tracking infant growth
spurts & lags are normal
head circumference is measured to assess brain growth
indicators of development problems
birth to 2 years: head circumference < 5th percentile or >95th percentile
indicators of stunted growth
birth to 2 years: length < 5th percentile
2 to 20 years: BMI <5th percentile
indicators of underweight
birth to 2 years: weight < 5th percentile
2 to 20 years: BMI <5th percentile
indicators of overweight
birth to 2 years: weight > 95th percentile
2 to 20 years: BMI >85th percentile and <95th percentile
indicators of obesity
2 to 20 years: BMI > 95th percentile or BMI >30 (whichever is smaller)
infant energy needs
infants have the greatest pound-for-pound need
BMR increases from birth to age 2 (by the pound, infant needs are 2-4x greater than adults)
rises slowly until puberty (large increase) & 30 (then declines)
children protein needs
infants: 1.5g protein /kg per day
children/adolescents: 1.1g protein /kg -er day (20-40% greater than adult needs per pound)
children fat needs
infants: fats = 40-55% of calories
- meet energy requirements without being overfull
children over 2 = same recommendations as adults
children carb needs
infants: primarily lactose
recommendations = the same across age groups
fiber is always important (AI = 14g/1,000 kcal for children less than 1 year old)
baby water needs
needs = met by breastmilk or formula
water intoxication = low requirement, limit supplemental fluids to 4 oz/day
nutrients of concern for children
- iron
- potassium
- calcium
- fluoride
- zinc
- folate
- Vit D
- Vit K
Infant feeding practices
human milk and/or formula meet all requirements until 6 months old
breastmilk benefits
most ideal source of nutrients
composition & bioavailability = engineered to meet infant requirements
contains:
- antibodies
- hormones
- immune factors
- growth factors
- enzymes
infant formulas
iron-fortified formulas are safe, nutritious alternatives
- attempt to match breastmilk as closely as possible
introduction of solid foods
infants must show signs of interest (watches spoon, able to self-support head, able to close mouth over spoon)
there is no benefit to early introduction of solid food
solid foods nutrition
nutrient needs = increased bc breastmilk is depleted & insufficient for growth
iron-containing foods = important (pureed meats, iron-fortified infant cereals)
solid food introduction sequence
introduce 1 single food ingredient at a time & wait 5-7 days before adding a new food
Iron & Vit C = first nutrients required
first foods = protein-rich with iron & Vit C (pureed meat, fish, chicken, beans, egg yolk, tofu)
avoid egg whites & cow’s milk (when cow’s milk is introduced, use whole milk until 2 years old, then 2% after that)
introduce lumpy foods when teeth appear
weaning
should be weaned from bottle by 18 months to prevent overconsumption of beverages & dental caries
self-feeding timetable
starts in late infancy & continues to develop until preschool years
- by age 1, drink from cup
- by age 2, lift, tilt, & lower cup, and use spoon
- by ages 3-4, use fork
- by ages 4-5, use knife
division of responsibility in feeding
infants: parents = responsible for what, infants = responsible for how much
solid food: parents = responsible for what, when, & where
toddlers through adolescents: parents = responsible for what, when, & where; child = responsible for whether & how much
