WCS22 Physiology Of Lactation, Breast Feeding And Infant Feeding 2 Flashcards
(40 cards)
Normal newborn parameters
Term (37-42 week postmenstrual age):
- Birth weight:
<37 week: Premature baby
37 week: 2.8 kg
40 week: 3.4 kg (male), 3.2 kg (female) - Body length: 48-53 cm
- Head circumference: 33-37 cm
Prematurity and Growth parameters:
- AGA (Appropriate for Gestational Age): 10-90%
- SGA (Small for Gestational Age): <10% symmetrical / asymmetrical
- LGA (Large for Gestational Age): >90%
Low birth weight: <2.5 kg
Average birth weight of premature delivery:
- 28 weeks: 1.1 kg
- 32 weeks: 1.8 kg
- 34 weeks: 2.2 kg
Fluid requirement and body weight
Postnatal weight loss of up to **7% of birth weight due to **fluid loss
Start gaining weight from day ***5-7
Day 1: 60 ml/kg/day
Day 2: 90 ml/kg/day
Day 7 onwards: 150-180 ml/kg/day
Developmental maturation in utero
- Fetal swallowing as early as 11 weeks
- GIT anatomically complete by 24 weeks
- Peristalsis at 28 weeks
- Coordinated suckling and swallowing at 33-36 weeks
- Functional development continues into infancy - Digestion + Absorption
SpC OG:
Digestion:
- Lactase induction after birth
- Protein digestion efficient
- Fat - malabsorb 10-30% fat in preterm infants
Goal of nutritional support
- Achieve appropriate growth and development
- Compensate additional demand during disease state
- Prevent complications of nutritional deficiency / excess
Measuring growth standards in Chinese children
Growth charts
Which one to use?
- Local growth charts were derived from population with mixed feeding regimens e.g. formula, breast etc.
- WHO formulated a standard growth chart from solely breast fed infants from a healthy cohort
Nutritional requirement
- Energy
- basal metabolic rate
- activity
- thermoregulation
- costs of digestion and metabolism
- energy loss by fecal, urine
- heat loss by radiation and evaporation - Protein
- growth
- human milk adequate for normal term infants (2-2.5 g/kg/day)
- but **NOT adequate for preterm (3.5-4 g/kg/day)
- **Essential amino acids (in ***whey component of human milk) - Fat
- **40-52% of total caloric intake
- >=3% of total calories as Linoleic acid
- **LC-PUFA important for growth / development of Retina + Brain
—> n-3, n-6 essential fatty acid (LA, DHA, ARA) - Carbohydrates
- glycogen stored from start of 2nd trimester
- storage exhausted within 12-24 hours
- normal glucose utilisation rate in term infant = 4-6 mg/kg/min - Minerals
- Ca
- Fe - Vitamins
- ***Vit D - Water
Casein and Whey
Casein micelles
- complexes of proteins + salts
- 20-40% of proteins in human milk
- 80% in bovine milk
- acidification —> precipitates
***Whey proteins
- portion that remains soluble on acidification
—> α-Lactalbumin
—> Lactoferrin
—> Immunoproteins
—> Enzymes (lipase, lyzozyme)
Daily requirements in diseases
Respiratory distress syndrome (RDS)
- Water: ↓
- Energy: ↑
- CHO: ↑
- Protein: —
- Fat: —
Chronic lung disease (CLD)
- Water: ↓
- Energy: ↑↑
- CHO: ↓
- Protein: ↑
- Fat: ↑
Cyanotic heart disease
- Water: —
- Energy: ↑
- CHO: ↑
- Protein: ↑
- Fat: ↑
Heart failure
- Water: ↓
- Energy: ↑↑
- CHO: ↑
- Protein: ↑
- Fat: ↑
Sepsis
- Water: ↑
- Energy: ↑↑
- CHO: ↑
- Protein: ↑↑
- Fat: —
Necrotising enterocolitis (NEC)
- Water: ↑
- Energy: ↑↑
- CHO: ↑
- Protein: ↑
- Fat: ↑↑
IUGR
- Water: ↑
- Energy: ↑
- CHO: ↑
- Protein: ↑
- Fat: ↑
Breast is best
- Provide optimal source of nutrition
- **Composition + **Volume adjusted to meeting growing need of individual infants
- premature delivery —> high conc. of **Fat + **Protein
- Fat conc. ↑ during an individual feeding
- change of content as baby grows
- formula can only gear to infants with highest possible needs —> **metabolic excess
- Growth velocity, Protein and Fat accretion —> **Highest at birth and ↓ with age - Unique immunologic protection
- matches with sequence of postnatal development of immune system
- help adaptation of GI tract in switch from fetal to postnatal life
- 3 overlapping groups of bioactive agents
—> **Direct acting antimicrobial agents (against infection)
—> **Anti-inflammatory agents (against inflammation)
—> **Immunomodulating agents (against atopy)
—> little known about how bioactive agents produce effects
—> interactions between defence agents in human milk?
—> dynamic changes in immune systems of infants and mother?
—> simple addition of one component to formula unlikely to achieve real health benefits
- Reduce risk of illness: **GE, respiratory, UTI, etc.
- Long term protection against respiratory tract, GI infection, sudden infant death, obesity, CVS risk factors
- ***Higher intelligence
***Human milk vs Cow’s milk
More:
- Whey
- Vit A
- Vit C
- Vit E
- Lactoalbumin
- Lactoferrin
- IgA
Less:
- Vit B1, B2, B6, B12
- Vit D
- Vit K
- Fe (but is in much more absorbable form)
- Ca, PO4 (more in Cow’s milk but much lower absoption)
- Lactoglobulin
Bioactive factors in human milk
Antimicrobial agents
1. **Lactoferrin (Fe chelation, bacterial killing)
2. **Lysozyme (bacterial cell wall)
3. ***Secretory IgA (bacterial adherence sites, toxins)
4. Antimicrobial Mucin (S-fimbriated E coli)
5. Lactadherin (Rotavirus)
6. Oligosaccharides (enteric / respiratory pathogens)
Anti-inflammatory agents
1. Growth factors, EGF, TGF
2. Enzymes that degrade mediators (Platelet activating factor - acetylhydrolase, glutathione peroxidase)
3. Uric acid, Vit A, E, C
4. Cortisol
5. PGE2
6. Modulators of leukocytes (e.g. IL-10)
Immunomodulating agents
1. β-Casomorphin
2. Prolactin
3. α-Tocophrerol
4. Cytokines
5. Nucleotides
***Growth and nutrition of preterm infant
Achieve intrauterine growth rate (15-20 g/kg/day)
Preterm infant:
1. **↑ Energy expenditure
- temp loss, digestion, stress
2. **Disease conditions
- PDA, RDS
3. Low intake of protein and energy
4. Fecal loss
Problem:
1. **Highest growth needs
2. **Immature gut
3. ***Immature immune system
4. High risk of infection
Breastfeeding:
1. Prevention of NEC (Necrotising enterocolitis)
2. Improve feeding tolerance
3. Cognitive development
4. Mother infant bonding
Growth retardation
Failure of normal fetal growth caused by multiple adverse effects on the fetus / premature baby
Preterm formula
- ***Whey / Casein = 60:40
- Higher protein content
- ***MCT
- Ca / PO4 ratio ↑
- Higher Vit contents
- ***Less lactose
- Calorie 20-224 Cal/oz
Improve feeding tolerance:
Human milk as ***Minimal Enteral Nutrition (Trophic feeding)
Minimal Enteral Nutrition (Trophic feeding):
- feedings given at small volumes to stimulate development of the immature gastrointestinal (GI) tract
Advantages:
1. Help **maturation + adaption of premature GI tract
2. **Full enteral feeding achieved earlier than formula milk
3. Mothers who initiate lactation earlier are more likely to sustain
4. Psychological well-being of mothers (bonding)
Additives in Infant formula
- Lack all bioactive factors
- Lack evidence on long term health benefits
Colostrum
First form of milk produced by the mammary glands immediately following delivery of the newborn, comes in **small volumes
- **Yellow to orange in color
- **Thick + sticky
- **Low in volume (suits baby’s small stomach) but **high in concentrated nutrition
- **Low in fat; **high in carbohydrate (to prevent hypoglycaemia) and protein
- **Large amount of immune factors (antibodies, secretory IgA; leukocytes, protective white cell) —> called “liquid gold”
- **Extremely easy to digest
- **Laxative effect and helps baby pass early stools (early meconium)
First 24 hours:
- 2-10 ml per feed
- 30-40 ml/day
2nd 24 hours:
- 7-15 ml per feed
- 70-80 ml/day
3rd 24 hours (milk start to come in):
- 15-30 ml per feed
Day 5:
- 500 ml/day
1 month:
- 750-1000 ml/day
Benefits:
1. Containing all necessary nutrients
2. Protects against infection
3. ***Laxative effect
Solution to decline in breastfeeding
- WHO international code and national legislation on marketing of breastmilk substitutes
- WHO/UNICEF 10 steps to successful breastfeeding to solve poor hospital practices
***Feedback Inhibitor of Lactation
Milk contains a small whey protein: Feedback Inhibitor of Lactation (FIL)
—> -ve feedback to Acini cell
—> slow milk synthesis when milk accumulates in the breast (and more FIL is present)
—> speeds up when the breast is emptier (and less FIL is present)
—> more often and effectively your baby nurses, the more milk you will make
Ensure plentiful breast milk production:
1. Remove milk from breast efficiently (every 3-4 hours)
2. More suckling from baby increase prolactin production
***Imbalance of fore-hind milk
Foremilk:
- Mainly **low-fat milk
- **Higher in volume
- More watery
Hindmilk:
- More **fat globules
- **Lower in volume
- More ***nutrient rich
Excessive foremilk:
- more water soluble constituents such as lactose then fat
—> **excess lactose —> loose, frothy, green stools + symptoms of **Colic
—> **low fat intake —> inadequate intake of **fat-soluble vitamins
Solution:
Ensure babies are allowed to empty one breast first before offered another
Insufficient milk
2 causes:
1. Ineffective attachment
2. Infrequent feeding
Consequences of ineffective attachment (1, 2—>4):
1. Pain and damage to nipples —> soreness, cracks, engorgement, stasis
2. Breastmilk not removed effectively —> engorgement, stasis, unsatisfied baby, wants to feed often
3. Apparent poor milk supply —> frustrated baby, refuse to suckle
4. Breast milk production declines —> baby fails to gain weight
Causes of infrequent feeding
- Delayed first feed
- Misunderstanding about demand feeding
- Supplements
- Separation of mother and baby
- Pacifiers
- Lack of support
Doctor’s role
- Encourage skin contact and early feeding after delivery: Kangaroo care
- Value colostrum
- Avoid unnecessary supplements
- Keep mother and baby together
- Encourage frequent feeding
- Discourage pacifiers
- Prescribe medications with care
- Supportive and encouraging
Counter-regulatory response in hypoglycaemia
If babies are healthy, term, breastfed but sleepy (hypoglycaemia)
—> will not develop symptoms of hypoglycaemia
—> ∵ Counter-regulatory response
- Inhibit insulin secretion
- Breakdown glycogen reserves
- Synthesise glucose from substrate in liver
- Generate alternative fuel e.g. ketone bodies
Caring for healthy, term, sleepy babies
1. Skin contact and early feed
2. Frequent, extended access to breast
3. Express and give colostrum
4. Frequent observation
5. Examination to exclude underlying illness
