Lactation

Question 1

What is the primary form of protein in breast milk and what advantage does this provide?

Answer 1

Whey – rapid gastric emptying, forms softer “curd”, enhances mineral absorption;

Question 2

What kinds of fat are present in breast milk?

Answer 2

long-chain polyunsaturated fatty acids, including ω-3’s.

Question 3

Five immune or bio-active factors in breast milk

Answer 3

Lactoferrin
SIgA
Bioactive lipids and carbohydrates
Bifidus factor
Cellular elements (macrophages, lymphocytes, neutrophils, epithelial cells)

Question 4

What are the effects of lactoferrin?

Answer 4

• Antimicrobial activity when not conjugated to iron (apolactoferrin);
• binding excess iron prevents iron uptake and bacterial growth;
• bacterial and viral killing effects in combination with other host defense proteins

Question 5

Where does IgA come from and what are its effects?

Answer 5

• most prominent immunoglobin in human milk;
• synthesized by maternal intestinal lymphoid tissue in response to challenge by specific antigens
• rapidly transferred into milk
• neutralizes foreign antigens (within 3-4 days after maternal exposure).
• Levels highest in colostrum, then decline over first month, but persist through 2 yr of lactation; IgM, IgG, IgD, IgE also are present in human milk.

Question 6

What are bioactive lipids and carbohydrates and what effects do they have?

Answer 6

• Oligosaccharides and glycoproteins

- prevent attachment of pathogenic agents to epithelial lining of mucosal surfaces.

Question 7

What is Bifidus factor and what does it do?

Answer 7

• N-containing carbohydrate which supports growth of non-pathogenic Lactobacillus.
• Results in intestinal microbiome in BF infants is high in commensal/protective organisms & limited in pathogenic strains

Question 8

What comprises the cellular elements in breast milk and what effect do they have?

Answer 8

• macrophages, lymphocytes, neutrophils, epithelial cells, nucleotides; hormones & growth factors
• impact GI flora, immune function, intestinal integrity and function.

Question 9

What is the impact of malnourishment on maternal milk production?

Answer 9

Maternal malnutrition results in reduced milk supply but minimally alters macronutrient content. In adequately nourished women, additional energy and fluid intake does not affect volume.

Question 10

What is the daily energy requirement (in calories) for milk supply?

Answer 10

Lactation is a very energy and nutritionally demanding process; an additional 500 kcal/d is recommended during the first 6 mo of lactation (vs 300 kcal/d for late pregnancy); this figure is less than actual energy cost of full milk production and assumes utilization of maternal fat stores laid down during pregnancy.

Question 11

How does maternal intake of vitamins and minerals affect milk contents of each?

Answer 11

• Maternal diet affects content of vitamins in human milk

- most minerals content is independent of maternal intake (exceptions = selenium & iodine);

Question 12

How is milk volume influenced by maternal fluid intake?

Answer 12

• Fluid consumption is important for milk synthesis but fluid consumption above maintenance needs does not enhance milk production.

Question 13

What are the advantages of breastfeeding for the infant?

Answer 13

Immunologic protection:

• Acute illness: reduced rates of gastrointestinal infection, respiratory illness (LRI, wheezing), otitis media, sepsis, necrotizing enterocolitis (premature infants)
• Chronic conditions: obesity, ? celiac disease, childhood cancer
• Immune priming

Neurodevelopmental benefits: bonding; enhanced cognitive performance

Exclusive breastfeeding through ~ 6 mo has been identified as the single most important factor in prevention of deaths of children

Question 14

What are the advantages of breastfeeding for the mother?

Answer 14

• Prevention of postpartum hemorrhage
• Weight loss (average return to pre-pregnancy weight after ~ 6 mo of lactation)
• Lactational amenorrhea/birth spacing; amenorrhea also spares nutrients, esp Fe
• Reduced risk of some chronic conditions (e.g. pre-menopausal breast cancer, osteoporosis)
• Bonding/stress reduction
• Economic benefit: savings in medical expenses due to reduced incidence of acute illness in breastfed infants; formula costs $650-2400/yr. N.B. Breastfeeding is not be “free,” esp if mother needs pump to maintain milk supply during separations from infant; purchase price of “hospital grade” pumps $150-350; rental costs $30-75/month.

Question 15

What are the WHO recommendations regarding breastfeeding for HIV+ women?

Answer 15

Women (& infants) should receive antiretroviral therapy (ART) and BF x 12 mo; exclusive BF more protective than mixed BF. If ART not available, must carefully consider alternatives to BF (e.g. formula availability, affordable, safety, etc)

Question 16

What is the Baby Friendly Hospital Initiative and what are the required steps?

Answer 16

The BFHI promotes, protects, and supports breastfeeding through 10 Steps to Successful Breastfeeding for Hospitals, as outlined by UNICEF/WHO. www.unicef.org

10 Steps:

1. Maintain a written breastfeeding policy that is routinely communicated to all health care staff
2. Train all health care staff in skills necessary to implement this policy
3. Inform all pregnant women about the benefits and management of breastfeeding
4. Help mothers initiate breastfeeding within 30 minutes of birth
5. Show mothers how to breastfeed and how to maintain lactation, even if they are separated from their infants
6. Give infants no food or drink other than breast milk, unless medically indicated
7. Practice “rooming in” – allow mothers and infants to remain together 24 hr a day
8. Encourage unrestricted breastfeeding
9. Give no pacifiers or artificial nipples to breastfeeding infants
10. Foster the establishment of breastfeeding support groups and refer mothers to them on discharge from the hospital or clinic.

Question 17

Why do the AAP and WHO recommend nursing infants within one hour of birth, and what steps should be taken to encourage this?

Answer 17

Infants placed on the abdomen and “self-attach” to the breast and nurse within 1 hr have better breastfeeding outcomes: ↑ number who continue BF at 2-4 mo postpartum:
o Delay routine procedures as possible: weighing, Vit K shot, eye prophylaxis
o Skin-to-skin contact in delivery room helps maintain body temp
o Infant typically alert & active x ~ 1 hr after delivery, then ↑ sleepiness

Question 18

What hospital practices have a positive effect on breast feeding?

Answer 18

Baby to breast in delivery room			
“Rooming-in”; BF assistance			
Staff initiate BF support w/ mo			
Mother seeing other mothers BF			
Ad lib nursing/feeding schedules

Question 19

What hospital practices have a negative effect on breast feeding?

Answer 19

Mother-infant separation at birth
Mother-infant housed on separate floors 
Mother encouraged to “get your rest,” “take it easy”
Pictures of bottle feeding 
Formula feeding  
Discharge packs w/ formula kit

Question 20

Because milk “comes in” – 3-4 days after birth, how are infant’s nutritional needs met from birth - 4 days?

Answer 20

Colostrum (from breasts), Glycogen, Low blood glucose, Epinephrine, & Fat stores

• Colostrum: high protein and antibodies, cells (esp neutrophils); low volume
• Glycogen (synthesis stimulated by intrauterine glucocorticoids; glycogenolysis utilizes glycogen stores x ~ 12 hr;
• “Low” blood glucose (40-50 mg/dl) → ↓ insulin & ↑ glucagon → gluconeogenesis
• Epinephrine stimulated by hypoglycemia, hypothermia, hypoxia; ↑ epi → tissue lipase →TG → Glycerol & FFA; +ketones
• Fat stores: brown & white fat provide substrate for energy intake; glucagon → hormone sensitive lipase in adipose tissue → oxidation of fatty acids (& glycerol → glucose)

Question 21

What are the weight parameters that indicate possible feeding deficiencies?

Answer 21

Weight loss greater than 7%, or weight under birth weight by 2 weeks.
• ↓ weight x 2-4 days = normal (diuresis); wt loss should not continue once milk comes in; weight loss greater than 7% may indicate inadequate milk intake; by day 4-5, should start gaining weight (15-30 g/d) & birth weight re-achieved by day 7-10.
• Weight loss greater than 7% and/or weight under birth weight at 2 wk: insufficient milk syndrome;

Question 22

What are the possible causes of feeding deficiencies?

Answer 22

Most commonly due to inadequate milk removal → inadequate milk production (Primary insufficient milk rare: ~ 5% of women)
o Maternal causes (e.g. emotional stress, medical problems, older maternal age, mixed feeding, breast surgery, separation from infant)
o Infant causes (e.g. low birth weight or prematurity, problems with latching on, neurologic problems, excessively sleepy, formula supplementation)

Question 23

How does newborn weigh loss differ in bottle fed infants?

Answer 23

• Formula fed infants generally don’t have same degree of weight loss
• Rapid rate of weight gain in first week of life is correlated with BMI at age 7 yr!

Question 24

What are infant formulas based on, and what modifications have been made?

Answer 24

Modern standard infant formulas are based on cow milk, which has been modified to mimic composition of human milk; (↓ protein, alter fat blend, nutrient fortified, etc)
• Recent trials suggest intact cow milk protein may cause increased risk of atopic disease (eczema, asthma, allergy); possible benefit of partially hydrolyzed cow milk protein to prevention of atopic disease, Type1 diabetes, et al