Lecture 24: Lactation II

Question 2

The Stages of Lactation: stage 1

Answer 2

Lactogenesis Stage I: preperation

• Mid gestation to day 2 postportum (breast capable from mid gestation but lactation doesn’t usually occur to post-partuition)
• Withdrawal of the Placental steroids is responsible; as this removes the inhibitory affect of E₂ and P₄ on breast response to prolactin

Question 3

The Stages of Lactation: stage 2

Answer 3

Lactogenesis Stage II: start of larger-scale milk production

• PostPartuition days 3-8 first week
• Changes in Milk composition: Increase a-lactalbumin; decreased sodium and chloride in milk (less salt)
• Due to tight junctions in alveolar epithelium stopping salt getting through

Question 4

The stages of Lactation: Glactopoiesis

Answer 4

Maintainence of established milk secretion, main phase of large scale milk production

Question 5

The stages of Lactation: Involution

Answer 5

Approx 40 days after last feed; due to buildup of inhibiting substances, loss of prolactin secretion as no longer stimulated

Question 6

The stages of lactation: Summarised

Answer 6

1. Lactogenesis I: preperation
2. Lactogenesis II: start of production
3. Glactopoiesis: milk production
4. Involution: stopping

Question 7

What is the milk produced initially called, and how is it different to mature milk?

What is its very special purpose?!

Answer 7

Thick product called Colostrum

• Contains less sugar and less fat (less energy focus) then mature milk
• Colostrum contains more total protein and is rich in Antibodies, especially IgA
  
  • IgA is the immunoglobulin of your secretory immune system: link between GALT (gastric assoc. lymphoid tissue) and MALT (mammary assoc. lymphoid tissue) so when mums being exposed to something in gut, she produces an immune response mediated by IgA of secretory IS, will also be product in mammary glands → Antibodies transferred to baby and protecting them again organisms mums exposed to
  • This is essential to buiding the babies immune system which is poorly developed at birth

Question 8

Whats in Human Milk?

Draw out the full table of components and their functions

Answer 8

These components all work together to not just feed the baby but to protect it from pathogenic advances!

Question 9

What are the difference between Bovine and human milk?

Answer 9

• Humans take 4-6 months to double birth weight; most mammals do this quickly
• Therefore this tells us human milk must be specifically adapted for humans!

Lactose: for energy and melin production (we have 1.5x more0

• *Casein**: major protein
• *a-Lactalbumin**: part of the enzyme that produces lactose synthesis by promoting activty of galactocidal transferase enzyme (we have more)

Linoleic Acid: essential fatty acid that must be present in the diet (we have more)

Question 10

Why is it important to know there’s a significant difference between bovine and human milk?

Answer 10

Because formula is dervied from cow’s milk, so we need to realise no matter how much we modify it it’s not the same as being breast feed!

Question 11

What are the personal benefits of breasting feed for mum?

Answer 11

1. Spacing of offspring
   
   • exclusive BF for 6 months → lactational amenorrhea
   • May also → weight loss
2. Bonding to offspring
   
   • eye contact
3. enhances involution of the uterus
   
   • ​500-600 micron long myoepithelial cells need to shrink back to normal size
4. Protects against Type II Diabetes
5. Protects against Post-partum depression
6. Protects against breast cancer and ovarian cancer (if BF >12 months)

Question 12

How does breast feeding affect babies atopy (allergies)

Answer 12

• Exclusive breastfeeding is protective against developy atopy
  
  • 60% of infants who develop atopic eczema do so in first 12 months of life
  • Infant intestinal mucosa is permeable to proteins in the first 6-9 months
  • The protective IgA system that later soaks up allergens is also poorly functional at this point: babies IS bad at this point, not fully developed to 3-5 yrs
• Exclusive breastfeeding is protective against developy asthma
  
  • reduces risk to 0.7 of risk of non-BF infant

In those with family members with issue, risk is Halved

Question 13

What is the major Downside of Breast feeding?

Answer 13

Disease/drug Transmission from mum → baby

• HIV: accounts for 1/2 all infanct HIV infections worldwide
• Mastitis
• Hep B
• Alcohol
• caffiene
• Nicotine

You need to weigh up the pros/cons of breast feeding to formula feeding! Easier in NZ as formula feeding is a viable option

Question 14

Mastitis risk and breast feeding?

Answer 14

Mastitis: infection of a lactiferous lobe; often a bacterial infection

Symptoms: a red triangle on the breast

This is not an indication to stop breastfeeding, we want to avoid stasis in the ducts.

Treatment: antibiotics