Breastfeeding Education for Physicians: The Road to Baby-Friendly Designation

Breastfeeding Education

for Physicians: 

The Road to Baby

Friendly Designation

Jennifer Amrol, MD

Assistant Professor of Clinical Pediatrics

University of South Carolina School of Medicine



Review the anatomy and physiology of breastfeeding.



Examine the composition of human milk and the

significance of individual components.

Objectives

Breast Anatomy



Exterior breast



Located between 2nd rib and 6th intercostal space



Main blood supply: 60% from internal mammary artery and 30% from

lateral thoracic artery



Innervated primarily by 4th intercostal nerve



Mammary tissue



Alveoli



Ducts



Nipple and Areola



Supporting connective tissue and fat, blood and lymphatic vessels,

nerves



Adipose tissue distribution greatly differs among women and is not

related to milk production

Breast



Mammary tissue



Alveoli



Small sacs of milk secreting and storing cells clustered into lobules



Surrounded by myoepithelial cells which contract in response to

oxytocin for milk ejection



Ducts



Connect lobules to form distinct mammary lobe



Then connect lobes to end at the galactophore



Ducts beneath areola become fuller due to oxytocin during a feed



Number is not related to milk production

Breast Anatomy



Areola



Circular and pigmented



Contains smooth muscle and elastic connective tissue



Darkens and enlarges during pregnancy



Contains Montgomery tubercles (or glands) which provide lubrication

which is bacteriostatic; may produce a scent to help infant find the nipple



Shape and size vary between women



Nipple



Has an average of 9 milk ducts passing to outside (range 4-18)



Has smooth muscle fibers and sensory nerves



Shape and size vary between women

Breast Anatomy



Women with inverted nipples can breastfed but they many need more help

postpartum.



She should request assistance with breastfeeding as soon as possible after

her baby is born.



After delivery, a breast pump might be useful to help evert the nipples.  If a

pump is not available, a 20ml syringe with the adaptor end cut off and the

plunger inserted backwards is used to help draw out a nipple.



Avoid bottle and pacifier use so the baby does not become accustomed to

the longer artificial nipple which feels and flows differently.



When all else fails, an ultra-think silicone nipple shield can be tried

temporarily.



Nipple preparation during pregnancy is not recommended

.

Inverted Nipples



Mammogenesis



Growth of the breasts



In utero, prepubertal, pubertal



Lactogenesis



Functional change of the breasts so that they can secrete milk



Occurs during pregnancy and initial postpartum period



Galactopoiesis



Maintaining the production of milk



Begins 9 days postpartum



Involution



Termination of milk production



With weaning

Stages of Lactation



In utero



Mammary bulb is seen at 18-19 weeks gestation



Fat pad precursor develops



Rudimentary ductal system is present at birth



After birth/before puberty



Small set of branching ducts grows with child



Remains inactive

Mammogenesis



Puberty -Thelarche



Takes 3 to 3 ½ years



Occurs 2 ½ to 3 years prior to menarche



Initial stages



Increase in size and pigmentation of areola



Development of breast bud

Mammogenesis



Puberty -Thelarche



Estrogen



Breast tissue enlarges



Stimulates growth of mammary ducts into preexisting fat pad



Progesterone



Effect begins with onset of menses and ovulation



Secreted by ovary during luteal phase (second half of

menstrual cycle)



Stimulates lobulo-alveolar development



Alveolar clusters grow with each luteal phase and regress with

onset of menses and loss of hormones

Mammogenesis



Mammary gland develops capacity to secrete milk



Includes all steps needed to transform undifferentiated breast

tissue in early pregnancy to fully differentiated state after

pregnancy



Two stages



Beginning at the twelfth week of pregnancy (Lactogenesis Stage 1)



Beginning shortly after delivery (Lactogenesis Stage 2)

Lactogenesis



Occurs by mid pregnancy



Pregnancy hormones



Progesterone



Lactogenic hormones



Prolactin and Human placental hormone



Stimulate nipple and areolar growth



Breast changes



Double in weight



Increased blood flow



Growth in lobules and alveoli (progesterone effect)



Increased secretory activity



Mammary gland becomes competent to secrete milk



Alveoli accumulate colostrum



Colostrum is secreted immediately postpartum when the newborn feeds



Milk secretion is prevented by elevated levels of estrogen and progesterone

Lactogenesis Stage 1



Occurs whether or not the newborn breastfeeds



Day 2 or 3 to day 8 after birth



Average of 40 hours postpartum



Earlier in multiparous women



Tight junction in alveolar cell closes



Onset of copious milk secretion



Drop in levels of estrogen and progesterone



Relative increase in prolactin levels



Breasts are full and warm



Switch from endocrine to autocrine control



Continued milk production depends on regular milk removal

Lactogenesis Stage 2



Blood flow, oxygen, and glucose uptake increase



Progesterone



Removal of placenta with its progesterone is required for milk

secretion



Progesterone receptors appear to be lost in lactating tissues so that

the inhibitory effect of circulating progesterone is decreased once

lactation is established



So progesterone only birth control can be used once lactation is going well



Insulin, GH, cortisol, and PTH



Maternal secretion allows for mobilization of nutrients and minerals

required for lactation

Lactogenesis Stage 2



Begins 9 days after birth and continues until weaning



Established milk secretion/production is maintained



Continued autocrine system of control



Prolactin



Required to maintain milk secretion



Oxytocin



Required to produce let-down to allow milk extraction

Galactopoesis



Begins at weaning



Regular milk extraction ceases



Prolactin is withdrawn



Is completed ~40 days after last breastfeeding



Milk secretion decreases due to the buildup of inhibitory

peptides



Mammary gland returns nearly to pre-pregnancy state

Involution



The cyclical process of milk synthesis and secretion



Occurs with the help of prolactin and oxytocin



Regulation of milk synthesis



Quite efficient



Average of ~800 ml/day but volume secreted may vary depending on

infant’s requirement



Milk production



Improves with relaxation



Decreases with maternal stress and fatigue



Increased dopamine and/or norepinephrine inhibit prolactin synthesis



Stress and fatigue inhibit oxytocin release



Effect of Alcohol



Lower levels may enhance milk letdown due to decreased stress but higher

doses inhibit oxytocin release thereby inhibiting letdown

Lactation

Physiology of Lactation



Prolactin



Polypeptide hormone synthesized in the anterior pituitary



Positive regulation of secretion



Released from anterior pituitary with the peak determined by the

intensity of suckling by the infant



Negative regulation of secretion



Main control is from hypothalamic inhibitory factors (dopamine

acts through the D2 receptors in lactotrophs)



Stimulates mammary gland ductal growth and epithelial cell

proliferation



Stimulates milk synthesis in mammary gland epithelial cells



Suppresses ovulation

Physiology of Lactation



Prolactin



Levels increase from 10-20 ng/ml in prepregnant state to ~200-

400 ng/ml at term



Levels slowly decline but continue to rise and fall in proportion to

frequency, intensity, and duration of nipple stimulation



Will remain elevated as long as mother breastfeeds



Prolactin concentration in blood doubles in response to infant

suckling and peaks ~45 minutes after initiation of feed



More feeds lead to higher serum prolactin levels



Makes mother feels relaxed and sleepy

Physiology of Lactation



Prolactin



Levels follow a circadian rhythm (ie levels are higher at

night)



Nocturnal feeds are helpful in keeping up supply initially



Levels drop with cigarette smoking



Levels are lower in mothers with depression



If lidocaine is applied to nipples, the loss of sensation results

in absence of increased prolactin levels in response to

suckling

Physiology of Lactation

Physiology of Lactation



Oxytocin



Synthesized in hypothalamus and stored in the posterior pituitary



Release is stimulated by suckling



Neuroendocrine reflex has a significant psychological component



Oxytocin release may be stimulated by thought, sight, or sound of infant



Stimulates myoepithelial cells in alveoli to contract and expel milk



Forcible milk removal is called milk ejection or let-down



Variation in perception of let-down



Increases temperature of mother's breast to provide warmth for

infant



Increases calmness, social responsiveness, and enhances bonding



Aids in uterine involution after delivery



Uterine contractions may be associated with “after pains” that indicate

oxytocin release

Physiology of Lactation



Signs of Oxytocin Release



Tingling sensation in breast before or during a feed



Milk flowing when mother thinks of baby or hears crying

baby



Milk flowing from other breast during feeding



Milk streaming from breast if latch is interrupted



Slow deep sucks and swallows by the baby during feed



Uterine pain during feed



Thirst during a feed

Physiology of Lactation



Milk production



Positive local regulation by demand

1.

Increased suckling

2.

Increased emptying

3.

Increased milk secretion/production



Skin to Skin (SSC) supports successful breastfeeding



Partial milk removal sets a new, lower rate of milk production



Negative local regulation of milk production



Feedback Inhibitor of Lactation



Accumulates in milk between feeds so without removal of milk, secretion/production

is inhibited



Explains why an empty breast makes milk faster than a fuller one



Distention or stretch of the alveoli



Local effect to inhibit milk secretion/production



Once milk removal stops, involution begins

Physiology of Lactation



Feedback Inhibitor of Lactation



Inhibitory whey protein present in breast milk



Builds up as milk accumulates in the mammary gland



Without milk removal, the inhibitor stops epithelial cells from

secreting/producing more milk



Protects breast from harmful effects of overfilling



Once milk is removed, secretion restarts



Allows production of milk to be determined by infant’s needs



Especially important regulatory mechanism once lactation is

established since prolactin does not control milk volume

produced

Physiology of Lactation



Mothers make nourishing milk for their infants from all kinds of food.

There are no foods that must be avoided, unless mother or baby

develops an allergic reaction.



Breastfeeding mothers have an increased thirst that usually maintains

an adequate fluid intake; no data support the assumption that

increasing fluid intake will increase milk volume.



Mothers do not need to drink milk to make milk; thirst can be satisfied

from a variety of nourishing beverages, including water.



Calcium is available not only in milk and milk products but in many other

foods, such as broccoli, spinach, kale, bok choy, collards, mustard and

turnip greens, almonds, and canned fish.



Poor maternal nutrition is not a contraindication to breastfeeding.



Mothers following a vegan diet should take a B12 supplement.

Maternal Diet and Milk Supply



Metoclopramide — most commonly used



Domperidone — not approved in USA. Similar to

metoclopramide but less side effects as little crosses

blood brain barrier



Fenugreek and other herbal medicines — no scientific

data except anecdotal reports



Goat’s rue, milk thistle, anise, basil, blessed thistle, fennel

seeds and marshmallow



Need more high quality studies to assess affect

Galactagogues



Effect is to increase prolactin level



Benefit  shown in small placebo controlled crossover study with

increase of 50 cc per feed with dose of at least 30 mg per day



Side effects



gastrointestinal, anxiety, sedation, and rare dystonic reactions



No documented neonatal reactions



Short term: 1–3 weeks is common



No evidence supporting long-term use



Usually wean after 10–14 days



Common dosing regimen



10 mg po qd first day



Then 10 mg po bid



Then 10 mg po tid

Metoclopramide



Most commonly recommended herbal galactogogue



Usual dose is 1-4 capsules (580-610mg) tid to qid



No standard dosing



May also be taken as one cup of strained tea tid



¼ tsp seeds steeped in 8oz water for 10 minutes



Increases supply within 24 to 72 hours



Side effects in mother



Maple like odor to sweat, milk, and urine



Diarrhea



Increased asthmatic symptoms



Lower blood sugar



Contraindicated during pregnancy due to uterine stimulant effects

Fenugreek

Human Milk Composition



Colostrum



Denser milk provided for the first 2-3 days after birth



Facilitates the passage of meconium to decrease enterohepatic circulation and

thus encourage elimination of bilirubin



Aids in establishment of 

Lactobacillus bifidus

 flora in infant’s gut



Milk Volumes



Day 1 40-50 ml 

(range of 7-123ml)



Day 3 300-400 ml



Day 5 500-800 ml



Low volumes encourage frequent feeds to stimulate milk synthesis



Colostrum Energy Value



67 kcal/100ml



Colostrum components



Higher concentrations of Na, K, and Cl than mature milk



Higher percentage of protein, minerals, and fat soluble vitamins than mature

milk

Human Milk Composition



Colostrum



Denser milk with 

higher concentration of proteins



White cells and antibodies (especially sIgA)



Important immune protection from exposures to environmental micro-

organisms



40-60% of cells are macrophages



Epidermal growth factor



Prepares gut lining to receive nutrients in milk



Lactose



Prevents hypoglycemia and facilitates meconium passage and therefore

bilirubin excretion



Vitamin A



Protects the eyes and epithelial surfaces



Beta carotene, its precursor, provides yellowish color of colostrum

Human Milk Composition

Immunoglobulins in Human Milk

(levels decrease over time)

Output - mg/24 hours

Day Postpartum

IgG

IgM

IgA

1 

   80     

120   

11,000

3 

   50      

40     

2,000

7 

   25       

 10      

1,000

8 – 50 

   10       

 10      

1,000

Human Milk Composition

Human Milk Composition

Note the 

increases in calories, lactose, and fat 

while the protein

decreases

 from colostrum to mature milk

.



Transitional Milk



Milk produced from days 5-14



Intermediate composition between

colostrum and mature milk



Volume continues to increase



Macrophage as percentage of WBCs

increases to 80-90%



Concentration is 10

4

 to 10

5

 per ml of milk

Human Milk Composition



Mature Milk



Milk produced after ~14 days



Contains all the nutrients an infant needs for the

first 6 months of life and is uniquely specific for

humans



Fat (3.8%), protein (0.9%), carbohydrates (7.2%), vitamins,

minerals, and water (87%)



Is easily digested and efficiently used



Composition varies through lactation: over a day,

within a feed, and between women



Calories



20 calories per ounce (65-

75

 kcal/100ml)

Human Milk Composition

Formula 

 Breast

Milk

               Milk

Note the substantial structure

of human milk under a

microscope; this is due to the

compartmentation of the

various components such as

the nutrients and bioactive

substances. This image

demonstrates that milk is a

living tissue containing about

4000 cells/cubic mm including

neutrophils, macrophages,

and lymphocytes.



Water



Human milk is 87% water



Provides sufficient fluid to maintain hydration even in

hot climates

Human Milk Composition



Fat content



3.5-3.8g/100ml provides 50% of energy/calories in milk



Most variable component of human milk



Separates on standing



Contains cholesterol, triglycerides, short-chain fatty acids, and

long-chain polyunsaturated fatty acids



Foremilk



Milk that accumulates in breast since previous feed



Lower fat content (1.5 to 2%) and looks bluish-gray



Hindmilk



Milk that is secreted during a feed



Higher fat content (2-3x more than foremilk- 5 to 6%) and

looks creamy white

Human Milk Composition

Fat



Fat content increases from the start of a feed (~1.7%)to

the end of a feed (~5.5%).



Protein content decreases from the start (0.9%) of a

feed to the end (0.7%).



Foremilk has less fat

but mor

e protein 

than

    hindmilk.

Human Milk Composition



Lipid Component



Milk fat globule



Forms with lipid secretion from apical mammary

epithelial cell and envelopment in its plasma membrane



Also contains proteins, growth factors, and vitamins



Mucins on the globule membrane adhere to viruses and

bacteria to aid in elimination from body

Human Milk Composition

Fat



Lipid Component



Bile salt-stimulated 

lipase



Acts on triglycerides to produce free fatty acids and 2-

monoglycerides



Prevents fatty acids from forming soaps with minerals



Results in superior absorption of fat and minerals



Not present in formula

Human Milk Composition

Fat



Lipid Component



Abundance of essential fatty acids (linoleic and linolenic

acids)



Most exist as triacylglycerols and phospholipids



167 fatty acids have been identified in human milk



Unique long chain polyunsaturated fatty acids (including omega-

3 fatty acids DHA and ARA)



Term infants are able to convert long chain polyunsaturated fatty

acids to DHA and ARA so the addition of these to term formulas

may be unnecessary but is likely useful for preterm infants who

cannot convert them.



Cholesterol is also present in significant quantities

Human Milk Composition

Fat



Human milk contains 9g protein/L (whey and casein)



Less than in other animal milks



Whey proteins consist primarily of 

α

-lactalbumin

without 

β

-lactalbumin



Cow milk whey contains 

β

-lactalbumin to which infants can

become intolerant



Contains less casein than other milks



Provides 80% of milk’s nitrogen



Protein content declines over 2-4 weeks but then is constant

until weaning

Human Milk Composition

Protein



Colostrum



90/10 ratio of whey/casein



Mature Milk



70/30 ratio of whey/casein



Late Lactation



50/50 ratio of whey/casein



Cow Milk



18/82 ratio of whey/casein

Human Milk Composition

Protein



Whey (70%)



Contains water, electrolytes, and proteins



α

-lactalbumin, albumin, lactoferrin, immunoglobulins,

enzymes (e.g., lysozyme), growth factors, and hormones



Remains in solution after acidification



Lactoferrin, lysozyme, and sIgA resist proteolytic

digestion and line the GI tract to provide host

defense



Present only in human milk



Generally more easily digested and associated with

more rapid gastric emptying

Human Milk Composition

Protein



Lactoferrin



Transports and promotes the absorption of iron



Inhibits the growth of iron-dependent bacteria in the

gastrointestinal tract such as coliforms and yeast



Lysozyme



Enzyme that protects the infant against E. Coli and Salmonella



Promotes the growth of healthy intestinal flora and has anti-

inflammatory functions



Secretory IgA



Primary Ig in breastmilk



Protects the infant from viruses and bacteria, specifically

those to which the baby, mom, and family are exposed



Helps protect against E. Coli

Human Milk Composition

Protein- Whey



Casein (30%)



β

-casein forms a soft curd in the infant’s stomach if pH<5



Curd is an insoluble calcium caseinate-calcium phosphate

complex



Low solubility in acid



Human milk casein curds are more easily digested than

those in other milks

Human Milk Composition

Protein



Non-protein nitrogen containing compounds



Provide 20% of nitrogen in milk



Epidermal growth factor



Contributes to the development and function of intestinal mucosa



Taurine



Free amino acid associated with bile acid conjugation and

neurotransmission



Nucleotides



Have metabolic and immune functions



Carnitine



Used for lipolysis of long-chain fatty acids



Somatomedin-C, Insulin and other peptides

Human Milk Composition



When is lactase present in the infant gut?



Present in maximal amounts in the intestinal

brush border of full term infants



Deficient before 34 wga

Human Milk Composition

Carbohydrates



Lactose (90%) 7.2g/L



Disaccharide of galactose and glucose synthesized in the breast



Important source of glucose



Important source of galactose for galactolipids used in infant brain

development



Monosaccharides, oligosaccharides, and glycoproteins (10%)



Oligosaccharides prevent bacteria from adhering to mucosal surface



Oligosaccharides plus glycoproteins = “bifidus factor”



Stimulate growth and colonization of newborn’s gut with 

Lactobacillus bifidus

(beneficial bacteria that creates an acidic gut where harmful bacteria cannot

survive)

Human Milk Composition

Carbohydrates



Minerals



Content is similar between mammal milks but

concentrations, ratios, and bioavailability are species

specific



Lower quantities results in lower solute load for

immature renal system



Iron, sodium, potassium, calcium, magnesium, zinc,

and small amounts of copper, selenium, chromium,

manganese, molybdenum, and nickel



Zinc and Iron



Well absorbed from human milk



Zinc deficiency is rare in breastfed infants whose

mothers have adequate Zn intake

Human Milk Composition



Iron



100mcg/L versus formula with 12mg/L



50-100% of human milk iron is absorbed



4% of iron fortified formula iron is absorbed



Absorption is enhanced by high lactose and vitamin C

concentrations in human milk



Lactoferrin in whey binds iron



Increasing digestion and absorption of iron



Also makes iron unavailable to iron dependent bacteria in gut



Normal full-term infants can be exclusively breastfed for

6 months without becoming iron deficient

Human Milk Composition



Vitamins



Vitamin A, beta carotene, and vitamin E



Plentiful in colostrum and early transitional milk



Vitamin A protects against infection and aids early retinal development



Vitamin E protects red cells against hemolysis



Vitamin D



Sufficient only with adequate maternal diet and maternal and infant sun exposure



AAP recommends 400 IU/d for all breastfed infants until they are ingesting or

exposed to sufficient Vitamin D from other sources



Vitamin K



Poorly transported prenatally and also limited in human milk



All newborns must receive Vitamin K at birth



Vitamin B12



Mothers on vegan diets may produce B12 deficient milk so supplements are

recommended

Human Milk Composition

Examples of the Non-nutritional

Components of Human milk



Antimicrobial factors



secretory IgA, IgM, IgG

lactoferrin

lysozyme

complement C3

leukocytes

bifidus factor

lipids and fatty acids

antiviral mucins, GAGs

oligosaccharides



Cytokines and anti-inflammatory factors



tumour necrosis factor

interleukins

interferon-g

prostaglandins

a1-antichymotrypsin

a1-antitrypsin

platelet-activating factor: acetyl hydrolase



Transporters



lactoferrin (Fe)

folate binder

cobalamin binder

IgF binder

thyroxine binder

corticosteroid binder



Others



casomorphins

d -sleep peptides

nucleotides

DNA, RNA



Growth factors



epidermal (EGF)

nerve (NGF)

insulin-like (IGF)

transforming (TGF)

taurine

polyamines



Digestive enzymes



amylase

bile acid-stimulating esterase

bile acid-stimulating lipases

lipoprotein lipase



Hormones



feedback inhibitor of lactation (FIL)

insulin

prolactin

thyroid hormones

corticosteroids, ACTH

oxytocin

calcitonin

parathyroid hormone

erythropoietin



Potentially harmful substances



viruses (e.g., HIV)

aflatoxins

trans

-fatty acids

nicotine, caffeine

food allergens

PCBs, DDT, dioxins

radioisotopes

drugs

http://www.unu.edu/unupress/food/8F174e/8F174E04.htm



Passive Immunization  via the Enteromammary Pathway

Human Milk Composition

Maternal exposure

Maternal gut

Antigens

Lymphoblasts

Mesenteric node

Thoracic duct

Blood stream

Other mucosal surfaces

Breast tissue and breastmilk

Infant

gut

Lymphoblasts mature into

lymphocytes that produce

immunoglobulins that

move into the

bloodstream

Milk Composition Differences



Thank you for completing Section 2 of Breastfeeding

Education for Physicians. To obtain CME credit, please

click on the link below, provide your information and

complete the post-test

https://www.surveymonkey.com/s/BreastfeedingSectio

n2