Exam 3- Lactation Flashcards
Lactiferous sinus function
Storage of milk
Functional unit of breast
alveoli
Estrogen increase during puberty causes
duct growth and branching
Progesterone increase during puberty causes
alveoli growth
During pregnancy estrogen ______ and progesterone _____ causing the breasts to double in size
increases, increases twice as much
During lactation the breast increase to ___ times there adult size because of a decrease in ___ and ___ and an increase in ____ and ___.
estrogen and progesterone
prolactin and oxytocin
The first milk is called ____, first few days: 2-10 mL per feeding in first 2-3 days
colostrum
Milk in days 7-14
Transitional- rapid changes in composition and volume
Mature human milk
2 wks to 6 months, fully developed and supports healthy full term infants
Extended lactation milk
Beyond 6 mo, declining conc of vitamins and minerals
Milk is made ____in the ____
de novo synthesis, mammary gland
Lactose is made of ___ and ___ and its synthesis requires ___
glucose and galactose, a-lactalbumin
Protein comes from ____ and _____ and fats are ____ and _____ chain
casein and lactalbumins (amino acids)
short and medium chain
Nutrients are transferred (uptake) from the
maternal plasma
Nutrients from maternal plasma
- long chain fatty acids
- all vitamins and minerals
- immunoglobulins, enzymes
- harmful substances: drugs, alc, caffeine
Milk synthesis and secretion
most active during feeding
Milk release: infant suckling stimulates sensory neurons and initiates neural loop in the _____
hypothalamus
The anterior pituitary releases _____ which stimulates______
prolactin, milk production
The posterior pituitary releases ______ which stimulates
oxytocin, milk ejection (let-down reflex)
Milk ejection: Primary stimulus is ______
infant suckling (artificial pumping is less effective)
Factors affecting let down
- infant: proper position, adequate latch-on
- psychological: baby crying, embarrassment (e.g., nursing in public), fatigue/stress
Signs of successful letdown
- milk dripping
- tingling
- uterus contraction
Breastfeeding Benefits for Mom
- prolactin inhibits ovulation and menstruation
- oxytocin promotes uterine contraction, thereby reducing postpartum blood loss
- promote postpartum weight loss & return to pre-pregnant weight
- lower risk of breast and ovarian cancer
- increase maternal self-confidence and maternal-infant bonding
- convenient and cheap
Breastfeeding benefits to baby
- nutrient content matches human infant need
- many components of breast milk have immunologic benefits
- reduction in acute and chronic illness
- may help to prevent obesity later in life
- increased IQ
Barriers to breastfeeding in US
- Lack of knowledge
- social norms
- Poor family and social support
- Embarrassment
- Lactation problems
- employment and child care
- Barriers related to Health Services
Breastfeeding common problem: sore nipples
very common
- prevention: proper position and latch-on
- treatment: letting breasts air-dry, rubbing expressed milk
- reducing feeding frequency doesn’t help
Breastfeeding common problem: engorgement
- breasts overfilled with milk, difficult for infant to latch-on - common in 1st time mothers; peak time: 2-3 d postpartum
- treatment: warm compress; express milk until breast not hard
Breastfeeding common problem: Plugged duct
- localized blockage of milk resulting from milk stasis
- prevention: complete emptying of breasts
- treatment: warm compress, gentle massage
Breastfeeding less common problem: Low milk supply
- most likely due to not breastfeeding enough (i.e., frequency & duration)
- insufficient milk syndrome is uncommon, occurs only in 5% of women, caused by inadequate breast development
Breastfeeding less common problem: Flat/inverted nipples and let-down failure
- seek lactation consultant’s help
Breastfeeding less common problem: Mastitis
- inflammation of the breast, accompanied by fever and pain
- engorgement -> plugged duct -> mastitis
- treatment: antibiotics + effective removal of milk: keep nursing (antibodies=protective)
Alcohol consumption during breastfeeding
Effects on infant
best to avoid alcohol
-odor, decreased milk consumption, disrupt sleep and cognitive development
How long does it take to clear alcohol?
1 drink: 2-3 hrs
2: 4-5 hrs
3: 6-8 hrs
Caffeine consumption during breastfeeding
Moderate intake okay - only 1% goes into milk
Caffeine accumulates in young infants because
- ability to metabolize caffeine not fully developed until 3-4 mo
- symptoms: wakeful, hyperactive, fussy
Studies show that most infants can tolerate maternal consumption of caffeine up to
3-4 cups a day (can test by avoiding all caffeine-containing beverages for 2-3 weeks)
Breastfeeding maintenance: Supply and demand principle
- daily production is governed primarily by frequency & duration of breastfeeding (BF)
- critical in lactogenesis stages I and II when trying to establish BF; less influential after stage III
- pumping/expression: less efficient than nursing; wait until BF is established (after stage III)
Breastfeeding maintenance: size of breast
- determined by the amount of fat, not number of alveoli cells
- affects storage, not total amount produced
Breastfeeding maintenance: Breast surgery
- reduction/augmentation, implants
reduction: usually can’t breastfeed
implants: usually can
When not to breastfeed
-Infants with galactosemia
-Maternal infections : -HIV - human T-cell lymphotropic virus - untreated active tuberculosis (TB)
Maternal medications
- many medications are safe, e.g., Tylenol
- chemotherapy or radiation
- check LactMed database
- consult with physicians
Steps to successful breastfeeding (10 but just main)
- policy
- education
- support
- breastfeeding on demand (every 2-3 hours)
DRI for lactation: Requirement for non-pregnant, non-lactating (NPNL) woman plus
requirement to produce breast milk
Breast milk production: average daily amount
- 0-6 mo postpartum: 780 ml/day (in exclusive breastfeeding- solids at 4-6 mo)
- 7-12 mo postpartum: 600 ml/day
average caloric density of breast milk:
20 kcal/oz or 667 kcal/liter
- 0-6 mo: 500 kcal
- 7-12 mo: 400 kcal
Macronutrient content in breast milk
- CHO: ~80 g/liter
- protein: ~9 g/liter
- fat: ~35 g /liter
breast milk contains ___% of calories from fat and ___% of calories from protein
47, 5
Energy expenditure during lactation- Major components of energy expenditure
BMR, PA, cals needed to make milk
BMR: little change
PA: slightly decrease in early postpartum but variable among women
Calories needed to produce milk can be supplied by
- Energy mobilized from normal, postpartum weight loss (1/3 at delivery, 1/3 0-6 mo postpartum, 1/3 >6 mo postpartum)
- Energy intake from the diet
Energy mobilized from postpartum weight loss
- 0-6 mo postpartum: average ~5 kg = 0.8 kg/mo
- 7-12 mo postpartum: not all women continue to lose weight and the amount of weight loss highly variable among women; so, cannot count on this for milk production
Calories needed for milk production
-0-6 mo postpartum: 170 kcal can be supplied from normal weight loss, only 330 kcal need to be supplied from the diet
-7-12 mo postpartum: 400 calories from diet
Avg: 365 kcal/day
Energy need for pregnancy compared to lactation
Lactation: 365
Preg: 264
*energy requirement for lactation is higher than pregnancy and lactation needs more nutrients
Fat soluble vitamins that RDA increases in lactation
E and A
T/F: Protein requirement increases for both pregnancy and lactation
True
The water soluble vitamins have a higher requirement for lactation than pregnancy except for
Folate
The requirement for calcium
never changes
The requirement for iron increases in pregnancy and _____ in lactation
decreases
Iron requirement for lactation:
Exclusive breastfeeding before menstruation resumes EAR = (basal need + Fe needed in milk) / (% absorption)= (0.9 mg + 0.27 ) / 18%= 6.5 mg/day
RDA = 9 mg/day
*Although Fe-deficient anemia is common in lactating women, this is primarily due to blood loss during delivery and not increased Fe requirement for breast milk production
Why doesn’t calcium requirement change when 210 mg is needed to produce 780 ml of milk? Sources of Ca
- diet, bone and renal retention
Maintenance of calcium homeostasis:decreasing ca levels= increased absorption, ca release from bones, and increased ca retention in kidneys
What is the primary source of Ca for milk production?
Ca retention
Hypothesis in study of lactation
Ca supplement will decrease bone loss, greater benefit for lactating
Hypothesis in study of weaning
Ca supplement augments bone gain, benefit greater for lactating women
Purpose of?
Randomiziation
double blind
Placebo
decrease likely hood that results are due to something else
Treatment in lactation study
2, 500mg doses a day for 6 months, adequate vita D and iron
Treatment in weaning study
same as lactation but with no extra iron
Primary outcome measure in lactation and weaning study
Total body bone mass and lumbar spine bone density and radius
secondary outcome measures in lactation study
breast milk Ca increase?
What methods were used to estimate participants dietary Ca intake before and during study
Before: food frequency questionarre over past 3 months (retrospective= bias)
During: Pill counts, 3 day food records (portion size estimate)
How were subjects Ca intake compared to EAR and RDA
Most were lower than EAR
Results for lactating study
Ca supplement did not significantly increase bone density of lumbar spine in lactating women but helped non lactating women increase their bone density. The supplement was of greater benefit to lactating women.
Results for weaning study
Ca supplement increased bone augmentation in both lactating and non lactating groups but did not help lactating women more than non lactating
Does Ca supplementation increase Ca content in breast milk?
No
How does Ca content in breast milk change over time
Decreases
A dietary Ca supplement during lactation isnt needed bc
- doesnt increase intestinal Ca absorption
- doesnt prevent bone loss
Ca needs are met by ___ during lactation
-mobilizing bone Ca
-decreasing urinary Ca excretion
(in preg by increased rate of absorption)
