NTRN 328 Exam 1: Breastfeeding and Lactation

What are the functional units of the mammary glands?

Alveoli are the functional units of
mammary glands
• Each is composed of a cluster
of secretory cells with a duct
in the center

What line the alveoli?

Myoepithelial cells line the
alveoli
• Contract during letdown =
milk ejection

• Action of contraction is letdown → when it moves through the cells, duct, nipple, to baby 

What are the stages of lactogenesis?

• Lactogenesis 1

  • Duration: last trimester → 2-5 days after birth 

  • Milk formation begins; lactose and protein content of milk is very high 

    • Lactose is a type of carbohydrate → want it very concentrated because babies cannot take in a lot of volume at 5 days olds → very nutrient dense so they can get a lot within a few ml 

• Lactogenesis 2

  • Duration ~2-5 days after birth - ~10 days postpartum 

    • Increased blood flow to the breast; onset of copious milk secretion

    • Women do not produce lots of milk within the first days after birth 

      • Abt 1 oz → can be discouraging for women 

• Lactogenesis 3

  • Duration: begins at ~10 days after birth 

  • Milk composition is stable 

What two hormones are necessary for establishing and maintaining a milk supply? What do they do?

• Prolactin and oxytocin are necessary for establishing and maintaining a milk supply

• Prolactin 

  • Stimulated milk production 

    • Suckling of nipple → stimulated secretion of prolactin 

  • Tells alveolar cells to produce milk and it will then me housed in the cells 

• Oxytocin 

  • Enables milk in the cells to be pushed out of breast 

    • Contraction of myoepithelial cells surrounding alveoli leading to milk ejection 

  • Ejection of milk from the mammary gland 

    • Also stimulated by suckling 

Breast milk synthesis is related to what factors?

• Breast milk synthesis is related to:

  • How vigorously an infant nurses

  • How much time the infant is at the breast 

  • How many times per day the infant nurses

• The size of the breast does not limit a woman's ability to nurse 

• Rate of synthesis is variable between breasts and between feedings

Stimulation of adequate milk may require how many expressions a day?

8-12

When does a fetus begin to suckle?

• Suckling - fetus begins sucking at 18 weeks gestation

  • BUT By 34 weeks gestation, has adequate pace and rhythm to be nutritive 

    • Enough strength and stamina to do this at this point 

What reflexes are important for breastfeeding?

• Gag reflex: prevents infant from taking food and fluid into lungs

• Oral search reflex: infant opens mouth wide when close to breast while thrusting tongue forward 

• Rooting reflex: infant turns to the side when stimulated on that side 

• We want to get a good seal → around whole areola not just nipple → not a good seal leads to air coming in → causes baby to throw up shortly after eating 

• Like suckling, reflexes require appropriate positioning, adequate letdown, and milk production

How does a baby attach to the breast?

• Attachment 

  • Mother stimulates oral search reflex 

    • Holds breast so nipple is directly in front of the infant's mouth 

    • Touches lower lip with nipple → open mouth widely 

  • Mother brings infant to the breast

How do we identify hunger and satiety in an infant?

• Identifying hunger and satiety 

  • Hunger is signaled by infant by bringing hands to mouth, suckling on them, and moving head from side to side 

  • Crying is a late sign of hunger 

  • Allow infant to nurse on one breast as long as they want to ensure they get hindmilk 

what is hindmilk?

Hindmilk is the end of the milk supply which is more nutrient dense it has high fat content → provides satiety

what is the feeding frequency of a newborn?

• Feeding frequency 

  • Newborns: ~10-12 feeding/day

    • Stomach emptying occurs in ~1 ½ hours 

      • Babies are weak and get tired when feeding so they need to be fed often 

Discuss human milk and infant consumption

• Human milk is the only food needed by the majority of healthy infants for ~6 months

  • Nurtures and protects infants from infectious diseases

milk composition changes:

• Milk composition changes
– Over a single feeding
– Over a day
– Based on age of the infant
– Based on presence of infection in the breast
– With maternal nutrition status

What is colostrum?

• Colostrum 

  • First milk that is secreted in the first few days postpartum 

    • Very high in proteins 

    • Looks yellow because there is a lot of vitamin a content 

      • Fruits and veggies high in vitamin a are red, orange, and yellow 

  • Colostrum is so nutrient packed and dense and helpful and beneficial for infants to get in those first few days of life

Discuss water and energy content of human milk?

Water
• Major component in human milk
Energy
• ~0.65 kcal/mL
– Varies slightly - fat, protein & carbohydrate composition
• Lower in calories than human milk substitute (HMS)

Lipids in Human Milk

• Lipids in human breast milk 

  • Provide ½ of the calories in human milk 

    • Lower in foremilk and higher in hindmilk 

  • Effect of maternal diet on fat composition 

    • Fatty acid profile reflects dietary intake of mother

Fat composition of human milk

• Fat composition of human milk 

  • DHA (docosahexaenoic acid)

    • Influence by maternal DHA dietary intake 

    • Essential for brain and retinal development

      • Associated with higher IQ scores 

  • Cholesterol

    • Essential component of all cell membranes → needed for growth in development 

    • Higher in human milk than HMS

Protein in human milk

• Total proteins 

  • Decreased protein content than whole milks cow

    • 0.32g/fl oz vs 0.96 g/fl oz

  • Antiviral and antimicrobial effects 

  • Do not consume cows milk prior to 1 yo because of the high protein content → kidneys are still developing and not strong enough to process the high protein content

Casein in human milk

• Casein

  • A major protein in mature human milk 

    • ~40% of the protein content of human milk 

  • Facilitates calcium absorption

Whey in human milk

Whey
• Major protein in mature human milk
– ~60% of the total protein content of human milk
• Component of several mineral-, vitamin- & hormone-
binding proteins
• Antimicrobial activity

carbohydrates in human milk

• Lots of fat and lots of carbs in breast milk

• Lactose 

  • Dominant carbohydrate

  • Enhances calcium absorption

Vitamin A in human milk

Vitamin A
• Colostrum content is ~double that of mature milk
– Mature milk adequate to meet infant needs
• Some in the form of beta-carotene (yellow color)

fat soluble vitamin

Vitamin D in human milk

Vitamin D
• Adequate maternal dietary intake  mature milk
content should be adequate to meet infant needs
• Content reflective of mother’s exposure to sun

fat soluble vitamin

Vitamin E in human milk

• Vitamin E

  • Content adequate to meet the needs of term infants 

    • Not adequate for preterm infants

      • Fortify breastmilk → add supplement to moms milk → makes it more energy dense with more calories 

• Fat soluble vitamin

Vitamin K in human milk

• Vitamin K 

  • Infants not receiving a vitamin K injection at birth may be deficient 

    • Vitamin K is important for clotting 

    • When baby is born baby's blood and skin are very thin so we want that injection at birth

fat soluble vitamin

water soluble vitamins in human milk

Water-Soluble Vitamins
• Content reflective of maternal dietary/supplemental intake
• Milk of well-nourished women in the U.S.  provides
adequate nutrient quantities to meet infant needs

Minerals in human milk

• Bioavailability 

  • Most have increased bioavailability 

  • Exclusively breastfed infants have very low risk of anemia, despite low iron content of human milk because infants can absorb the little iron in human milk very well 

    • Formula fed is more likely to be anemic bc the iron in formula is not as bioavailable → even though they are putting more in the formula 

• Zinc 

  • Bound to protein and highly available 

    • Availability of human milk = 49%

    • Availability of cow’s milk and cow's milk HMS = 10%

• Trace Minerals 

  • Copper, selenium, chromium, manganese, molybdenum, nickel and fluoride 

    • Not altered by mother’s diet, except fluoride

What supplementation is recommended for breastfed infants

• Vitamin K 

  • All us infants receive injections at birth 

  • No injection = increased risk of deficiency

• Vitamin D

  • Supplementation recommended by American Academy of Pediatrics from birth - 18 years old → help prevent chronic disease

How do we identify breastfeeding malnutrition?

• Normal weight loss for newborns 

  • ~7% of birth weight in 1st week 

    • Normal to lose weight in first week of life 

    • Babies are able to now move which uses up a lot more energy 

    • No longer connected to the placenta and constantly receiving those nutrients 

  • Weight loss of 10% needs evaluation by lactation consult 

    • No intervention but close observation 

• Malnourished infants become sleey, non-responsive, have a weak cry, and few wet diapers 

  • By day 5-7: nourished infants should have 6 wet and 3-4 soiled diapers

What does human milk taste like?

• Taste of Human Milk 

  • Flavor of foods in mothers diet influences taste of breast milk

    • Infants seem more interested in mothers milk if flavor is new 

  • Exposure to a variety of flavors may contribute to infants interest and acceptance of new flavors in solid foods

What are the maternal benefits of breastfeeding?

• Hormonal benefits 

  • Increases oxytocin stimulates uterus to return to pre-pregnancy status 

• Physical benefits 

  • Delay in monthly ovulation resulting in longer intervals between pregnancy 

  • Suppresses secretion of FSH and LH 

• Psychological Benefits 

  • Increased self confidence and bonding with infant

What are the breastfeeding benefits to the infant?

• Immunological benefits 

  • Decreases infant mortality in developing countries

  • Fewer acute illnesses

• Reductions in chronic illness 

  • Decrease risk of celiac, IBS, allergies, and athmatic disease 

• Childhood weight status 

  • Childhood obesity is lower in those breastfed than those not 

• Cognitive benefits 

  • Studies show an increase in cognitive ability even after adjusting for family environment 

• Analgesic effects 

  • Decreased infant pain 

• Socioeconomic benefits 

  • Decreased need for medical care 

  • Decreased direct cost of feeding infant (not having to purchase HMS)

• Tooth decay 

  • Caries can occur in children who are breastfed and formula fed 

  • Risk factor is frequent nursing at night after 1 year 

  • All children should be seen by a dentist 6 months after 1st tooth erupts or at 1 year of age 

  • Formula and human milk have a lot of carbohydrates which has a lot of sugar

What are the energy needs for lactation?

• Less than 6 months of age → mom needs an addition 500 calories 

• More than 6 months of age → mom needs an addition 400 calories because solid foods are being introduced 

• Dietary reference intakes for women who are breastfeeding a baby less than 6 months is only 330 kcal and 400 kcal after 6 months 

• DRI is promoting weight loss in mom → accounts for discrepancy between two values

What does protein calorie malnutrition do to milk production?

• Protein calorie malnutrition 

  • Results in decreased milk volume but not quality 

    • Body will do its best to keep the quality but will reduce quantity

How does weight loss affect breastfeeding?

• Weight loss during breastfeeding
– Caloric DRI assumes a loss of 0.8 kg/month
(+330/+400)
• Most women do not reach pre-pregnancy weight by 1
year postpartum
– Modest or short-term energy reductions do not
decrease milk production

What other things about the maternal diet could affect breastfeeding?

• Other facts of maternal diet 

  • Vitamin and mineral supplements

    • Not needed in well nourished women 

  • Functional foods 

    • No adverse effects based on studies to date 

  • Fluids 

    • Women should drink to thirst 

    • Fluid intake is higher when mom is breast milk 

    • Not enough intake → quantity of milk decreases

  • Alternative diets 

    • Type of diet determines supplement that may be needed

What is infant colic?

• Infant Colic: crying for more than 3 hours/day - no medical cause 

  • Components of maternal diet may be related to infant colic 

  • More likely with: 

    • Cows milk, onions, cabbage, broccoli and chocolate 

  • Mothers should exclude foods that seem to cause problems 

    • Replace nutrients lost with the exclusion

How does exercise affect breastfeeding?

• Modest energy restriction combines with increased exercise may help women lose weight and body fat 

• Exercise does not inhibit milk production or infant growth 

  • As long as caloric intake sufficient

How does breastfeeding help with allergies?

• Allergies 

  • Exclusive breastfeeding for > 4 months protects against: 

    • Allergies, dermatitis, and respiratory complications 

  • Development of food allergies influenced by many factors 

    • Duration of breastfeeding 

    • Timing of introducing of other foods 

    • Genetics 

    • Exposure to infectious disease 

    • Maternal diet 

    • Immune system 

What is the optimal breastfeeding duration?

• Optimal breastfeeding duration
– WHO and U.S. Surgeon General recommendation:
exclusively breastfeed for first 6 months
• Breastfeeding goals for the U.S.
–  the proportion of infants breasted, as well as the
duration
– Breastfeeding rates in the U.S. are continuing to slowly
rise (81% initiation; 25.4% exclusive at 6 months)

What are some US disparities that exist when it comes to breastfeeding?

US Disparities with Breastfeeding

• Geography: some of the lowest rate among southern states 

  • Alabama, louisiana, mississippi

• Race/ethnicity: highest among asian and hispanic women and lowest among black women 

• SES: rates increasing with income level 

• Education and age: initiation and duration increased with education and age of mother 

• Marital status: rates higher among married women

What are some barriers to breastfeeding initiation?

• Embarrassment
• Time & social constraints
• Lack of support from family & friends
• Lack of confidence
• Concerns about diet & health
• Fear of pain

What types of support can be provided to help promote breastfeeding?

Prenatal Breastfeeding Education and Support
• Effective in  number of women who choose to
breastfeed
Lactation Support in Hospitals and Birthing Center
• Hospital practices can influence breastfeeding
– Baby Friendly Hospitals (1992)
• Distribution of free formula samples is discouraged

What kinds of things in the workplace make it difficult for breastfeeding to occur?

• Breastfeeding support is essential in the first few weeks
after delivery, as lactation is being established
• The workplace
– Lack on-site day care, rooms for pumping
– Insufficiently paid maternity leave
– Rigid work schedules
– Lack of knowledge by employers

What are some barriers to breastfeeding?

Barriers to breastfeeding may include:
– Lack of access to reliable & culturally appropriate
sources of information & social support
– Cultural perceptions of bottle feeding as norm
– Aggressive marketing by formula companies
– Laws that prohibit breastfeeding in public

Sore Nipples

Common when initiating breastfeeding
(Should subside by end of first week)
• Potential Causes:
– Poor positioning of infant at the breast; improper latch;
pumping with too much force; infection
• Prevention: proper positioning of baby on breast may help
– Areola should be in the baby’s mouth with tongue extended
against lower lip
• Treatment:
– NOT limiting breastfeeding; warm compress; air dry nipples
after nursing; rub expressed milk on nipples

Letdown Failure

• Occurs when milk does not eject from the breast

• Very uncommon
  • Oxytocin nasal spray may be prescribed
  • Relaxation techniques may help reduce problem

Hyperactive letdown

Streams of milk come from the breast
• More common among first time mothers
• If too active, may cause infant to choke while nursing
• Management:
– Mother may express milk until flow slows, then allow infant
to nurse
• Hindmilk
• Prevents gas and colic because of large volume of
relatively low-fat milk

Engorgement

Engorgement
Breasts are overfilled with milk
• Common in first week of birth and first time mothers
– Can  milk flow because swollen tissue compresses
breast
• Potential causes:
– Supply-and-demand not yet established  milk is abundant
– Mother-infant separation
– Sleepy baby

• Best prevention:
– Nurse frequently – newborns often nurse every 1½ hours
• Either at the breast or using a pump

Plugged Duct

Localized blockage of milk resulting from milk remaining
in the duct
• Painful knot may form in breast
• Prevention: complete emptying of breasts and changing
position of infant while feeding
• Treatment: massage, warm compress

Mastitis

Inflammation of the breast
• Most common at 2-3 weeks postpartum
– Occurs in up to 33% of breastfeeding women
• May be infective or non-infective
• Potential Causes:
– Sore and cracked nipples
– Missing a feeding  engorgement
– Plugged duct  engorgement

Low Milk Supply

• Most common reason for cessation of breastfeeding
– May be real or perceived
• Potential Causes:
– Insufficient breastfeeding or pumping
– Ineffective emptying
– Stress
• Management:
– Nurse/pump every 2-3 hours during the day, once at night
– Galactogogue may be prescribed

Breastfeeding Multiples

Breastfeeding Multiples
• Breastfeeding twins, triplets & quadruplets is possible
– Main obstacle is the time & fatigue of mother
• Frequent nursing  milk supply
• Parents of multiples need support in:
– Organization
– Feeding
– Individualization
– Stress management

What are some medical contraindications to breastfeeding?

Few medical problems in the mother or baby are
absolute contraindications to breastfeeding
• Some exceptions:
– Galactosemia diagnosis (infant)
– HIV (mom)
– Active TB (mom)
– Illicit drug use (mom)
– Chemotherapy or radiation treatment (mom)
• The theoretical risk must be measured against the
projected benefits of breastfeeding