Lactation Flashcards
lactation - general
- Following birth
- Provides milk of appropriate composition and quantity to fully sustain the growth and development of the young until weaning
- Breast changes are often the first subjective indication of conception
- Breast development during pregnancy = Secretory Differentiation
o Milk production after birth = Secretory Activation
secretory differentiation
- Breast growth during pregnancy occurs through terminal end buds
o Increasing Prolactin and Lactose levels during pregnancy linked to breast development - lactose secreted in the urine
o Terminal
pregnancy hormones that lead to breast growth
'lactogenic hormone complex' o oestrogen o progesterone o growth hormone o epidermal growth factor o fibroblast growth factor o insulin-like growth factor o parathyroid hormone related protein o human placental lactogen (hPL)
secretory activation
- Onset of copious milk secretion
- Day 1- 3 days - colostrum
o 7 - 123 mL per day
o Rich in protein - immunoglobulins, lysozyme and lactoferrin - Day 3 - 6 -> mature milk
o 400 - 900mL per day
o Change in milk composition
o inc lactose, inc water, inc protein - Following birth delivery of the placenta => dramatic fall in progesterone => Secretory Activation
- Progesterone withdrawal initiates Secretory Activation.
- Increase in Lactose associated with milk production.
- Initiation of copious milk secretion
hormones required for lactation
Permissive o Prolactin o Insulin o Adrenal Cortisol Trigger o Removal of progesterone Milk Ejection o Oxytocin Lactose synthesis determines milk volume (osmotic)
delayed secretory activation
May be caused by:
- Premature delivery
- Type1 Diabetes
- Obesity
- Prolactin insufficiency
- Delayed progesterone withdrawal (**retained placental fragments)
- Hormone therapy
- Anaesthetic agents (caesarean)
milk ejection reflex (MER)
stimuli can be conditioned and can be inhibited by stress - invasive procedures can reduce MER
stimulus: Sensory nerves, spinothalamic tract –> brain stem –> brain stem –> hypothalamus –> post pituitary –> oxytocin release –> maternal circulation –> receptor binding –> myoepithelial cell contraction –> milk ejection
autocrine control of milk synthesis
supply vs demand (appetite) and inhibition
local control of milk synthesis
short term: hours
medium term: days - weeks
long term: weeks - months
frequency of breastfeeding, in part, explain many problems such as
mastitis sore nipples reflux colic unsettled baby low supply over supply
brestmilk as a functional food - milk composition
contains nutrients and substances that confers health benefits
- lactose, protein, fat
benefits of breastfeeding for mother
- Recovery from childbirth
- Body weight loss
- Suppression of maternal fertility
- Bone mineralization
- Cholesterol clearance
- Diabetics – glucose control
- Decreased risk of breast & ovarian cancer
- Self esteem
benefits of breastfeeding for baby
- ‘Gold Standard’ Infant Food
- Ideal nutrition
- Species specific
- Facilitates Growth & Development
- Increased IQ
- Better eyesight
- Protect against illness
protein, fats, CHO, vitamins and minerals adapted to the infants digestive capacity and metabolic requirements
non-nutritional components of breastmilk
- Antimicrobial factors
- Growth factors
- Cytokines and anti-inflammatory factors
- Digestive enzymes
- Hormones
Complement Infant’s Immature Metabolic Capacity
- Digestive, Hepatic, Renal, Visual, Skeleton, Endocrine,
- Vascular, Immune, Central Nervous System
benefits for the immature digestive system
Breastmilk contains:
- Digestive Enzymes
- Glutamate/Glutamine (as free amino acids)
- Oligosaccharides
- Influences normal gut flora
- Enzymes promote gut maturation and gut repair
- Enzymes increase bio-availability of trace elements
- Promotes intestinal growth
o Taurine, ethanolamine, interferon
nervous system
components unique to human breastmilk to enhance brain development: +7 IQ points, dose dependent effect, visual and motor development
immune system
Specific defence - sIgA: generated by Mothers
response to environment
Non Specific Defence - Protective Molecules
- B12 binding proteins: Reduces B12 for bacterial growth
- Bifidus Factor: Promotes growth of good bacteria
- Fatty acids: Disrupts virus membranes
- Fibronectin: Activates macrophages, tissue repair
- Gamma-Interferon: Activates immune cells
- Hormones & Growth Factors: Promote maturation of GI tract
- Lactoferrin: Binds Fe, active peptide
- Lysozyme: Disrupts bacterial cell walls
- Mucins: Immobilises bacteria
- Oligosaccharides: Bind to bacteria prevents attachment
immune cells in milk
- B lymphocytes: Produce specific antibodies
- Macrophages: Kill microbes and produce lysozyme
- Neutrophils: May act as phagocytes
- T lymphocytes: Kill infected cells, mobilize defences
physiology of the preterm infant
- Premature infants body systems are even more immature than the term infant
- Glycine every 3rd AA in collagen, required for growth
- Non essential nutrient requirements may become conditionally essential eg: glycine*
- Alternate metabolic pathways eg: glucose phosphorlyation
- Preterm infants cannot suckle
- Mothers must express milk
- Milk must be supplemented to meet nutritional demands
- Many mothers of preterm infants cannot produce enough milk
breastmilk cells
- Breastmilk contains a diverse range of cells:
o Immune cells, e.g. Leucocytes, macrophages, neutrophils, T-cells, B-cells, (white blood cells)
o Epithelial cells, lactocytes and myoepithelial cells from the glands and ducts
during infection
- In healthy mothers and infants: < 1% immune cells
- Mother or Infant with an infection: Up to 20% immune cells
