This lecture is fundamentally about why breast milk is the ideal food for infants, how the breast makes and delivers milk (the physiology), what goes wrong (breast problems during lactation), and what to think about when prescribing drugs to a breastfeeding mother. It bridges O&G (puerperium, maternal health) and Paediatrics (infant nutrition, growth, infection prevention). Everything connects back to five principles of infant feeding, and the physiology explains why breastfeeding satisfies all five.

1. Principles of infant feeding
2. Benefits of breast feeding (infant, mother, socioeconomic)
3. Promotion of breast feeding (blocks, WHO 10 steps)
4. Physiology of lactation (anatomy, initiation, maintenance, weaning, ovulation suppression)
5. Breast problems (sore nipples, engorgement, ductal narrowing/mastitis spectrum, abscess)
6. Medication during breast feeding

Energy requirement: ~110 kcal/kg/day for infants 0–12 months ^[1]

• ~20% for growth, remainder for basal metabolism, thermoregulation, and activity
• Compare with adults: only ~40 kcal/kg/day (sedentary)
• Nitrogen requirement: 120 mg/kg/day in infants (similar to adults at 100 mg/kg/day, but per-kg it's higher – reflecting greater protein synthesis for growth)

Why does this matter clinically? If you miscalculate an infant's caloric needs or if feeds are inadequate, growth faltering (failure to thrive) happens rapidly because reserves are small and demand is proportionally huge. ^[1][2]

Specific amino acids (taurine, cysteine) and fatty acids (LC-PUFA, MCT) in breast milk are critical for brain and retinal development ^[1]

Carbohydrate:

• Main energy source (lactose is the predominant carbohydrate in breast milk)
• Lactose also promotes calcium absorption and supports healthy gut flora

Protein:

• Growth and tissue repair
• Taurine: deficiency causes irreversible retinal damage (demonstrated in growing kittens) – breast milk is rich in taurine
• Cysteine: newborns lack the enzyme to convert methionine → cysteine, so cysteine is an essential amino acid for neonates (it's conditionally essential). Breast milk provides it directly

Fat:

• Energy-dense (9 kcal/g) and supplies essential fatty acids
• LC-PUFA (long-chain polyunsaturated fatty acids): DHA and ARA are critical for brain and retinal development
• MCT (medium-chain triglycerides): absorbed more easily because they don't require bile salts for emulsification – important for the immature neonatal GI system
• Human milk supplies lipases, including bile-salt-stimulated lipase, that assist fat digestion in the immature gut; this is the physiological point behind the slide's “lipase in the fat globule” shorthand ^[1]

Minerals and vitamins:

• Especially iron and calcium ^[1]
• Note: breast milk iron is low in absolute quantity but has very high bioavailability (~50% absorbed vs ~10% from formula). Despite this, iron stores from birth deplete by ~4–6 months, which is why iron-fortified complementary foods are introduced ^[7]

The newborn's digestive system is not fully developed ^[1]

• No teeth, low gastric acid, low pepsin, low pancreatic lipase and amylase
• Casein curds form in the stomach and are harder to digest compared to whey protein ^[1]
  • Breast milk: whey:casein = 60:40 in mature milk (90:10 in colostrum) ^[2]
  • Cow's milk: whey:casein = 20:80 → much harder for infants to digest
• Human milk lipases supplement the infant's relatively immature pancreatic and bile-salt-dependent fat digestion ^[1][3]

In developing countries, the commonest cause of infant death is gastroenteritis ^[1]

• Formula feeding requires clean water, sterilised bottles, correct dilution – all of which may be unavailable
• Direct breastfeeding avoids water, bottle and mixing contamination and supplies anti-infective factors (sIgA, lactoferrin, lysozyme). Human milk is not literally sterile; it contains a microbiome
• Infection increases energy requirement → recurrent infection → stunted growth (vicious cycle) ^[1]

The deck states that early exposure to foreign protein increases eczema and asthma risk ^[1]. That reflects an older "allergen avoidance" model and needs qualification:

• Breastfeeding remains recommended for its nutritional and infectious-disease benefits, but it does not guarantee prevention of food allergy.
• Do not deliberately delay allergenic complementary foods. Complementary feeding generally begins at about 6 months (not before 4 months), once the infant is developmentally ready ^[20].
• In infants at high risk of peanut allergy (severe eczema and/or egg allergy), early age-appropriate peanut introduction is protective when performed according to risk assessment and, where indicated, supervised evaluation ^[21].
• The useful distinction is therefore: avoid unnecessary replacement of breast milk with intact cow's-milk formula, but do not turn that into prolonged allergen avoidance.

Preterm infants have higher energy needs (120 kcal/kg/day), are more susceptible to LC-PUFA and cysteine deficiency ^[1]

Breast milk perfectly matches all five principles of infant feeding ^[1]

Fertility control, bonding, uterine involution ^[1]

• Fertility control: via lactational amenorrhoea (prolactin suppresses GnRH → suppresses LH → no ovulation). Detailed criteria below.
• Bonding: oxytocin release during let-down promotes maternal-infant attachment
• Uterine involution: oxytocin causes uterine contraction → reduces postpartum haemorrhage and speeds return to pre-pregnancy uterine size

Additional maternal benefits from other sources ^[4]:

• Reduced risk of type 2 diabetes, breast cancer, ovarian cancer
• Promotes postpartum weight loss

Birth control, spacing pregnancies, decreased maternal death, prevention of infant infection/death, much less costly than bottle feeding ^[1]

• In resource-limited settings, these benefits are massive public health interventions
• Breastfeeding costs nothing vs formula (which is expensive and requires infrastructure)

Seven blocks identified in the lecture ^[1]:

1. Home and work environment – lack of maternity leave, no facilities at work
2. Attitude of society – stigma around public breastfeeding
3. Lack of public facilities – no nursing rooms
4. Lack of family support – pressure from family to use formula
5. Lack of support from health professionals – doctors/nurses not trained in lactation support
6. Promotion from formula milk companies – aggressive marketing
7. "A lost tradition" – urbanisation and formula availability have eroded breastfeeding culture

This is the framework for the Baby-Friendly Hospital Initiative (BFHI) ^[1]

Critical Management Procedures (Steps 1–2):

Key Clinical Practices (Steps 3–10):

The image-heavy policy slide shows the 10 steps translated into ward practice ^[1]:

• a written infant-feeding policy and staff training;
• antenatal discussion of benefits and practical management;
• immediate skin-to-skin contact and early initiation;
• teaching positioning, attachment and maintenance of supply during separation;
• no food or fluid other than breast milk unless medically indicated;
• 24-hour rooming-in and cue-responsive feeding;
• counselling on artificial teats/pacifiers and linkage to community/hotline support after discharge.

The poster also records QMH's Baby-Friendly Hospital designation in 2018. The key exam point is not the historical phone numbers or badge—it is how institutional policy removes barriers at each stage of the breastfeeding pathway.

Key structures: alveoli, adipose tissue, mammary/lactiferous ducts, areola, nipple ^[1]

• Alveoli: grape-like clusters of secretory epithelial cells surrounded by myoepithelial cells. This is where milk is actually produced.
• Myoepithelial cells: contractile cells that squeeze milk out of alveoli when stimulated by oxytocin
• Mammary ducts (lactiferous ducts): transport milk from lobules to nipple openings. Modern ultrasound found about 9 main ducts on average, branching close to the nipple ^[17]
• Areola: contains Montgomery's tubercles (sebaceous glands that lubricate nipple during lactation) ^[6]
• Nipple: contains the orifices of the lactiferous ducts
• Adipose tissue: determines breast size (but NOT milk-producing capacity)
• Cooper's ligaments: fibrous septae between lobules; not directly relevant to lactation but important in breast pathology ^[6]

Puberty: oestrogen → duct proliferation; progesterone → alveolar development ^[1]

Pregnancy: oestrogen + progesterone → further alveolar hypertrophy BUT inhibit milk production; prolactin (+ hPL) stimulate secretory activity ^[1]

Key concept: During pregnancy, prolactin levels are rising enormously, but actual milk secretion is suppressed by the high oestrogen and progesterone from the placenta. This is why delivery (and loss of the placenta) is the trigger for lactation.

Elevated prolactin + reduced GnRH → reduced LH → suppressed ovulation ^[1]

LAM is effective as contraception ONLY if all THREE criteria are met: ^[1]

1. Amenorrhoea
2. Fully or nearly fully breastfeeding (no interval > 4–6 hours between feeds)
3. < 6 months postpartum

Why does this work?

• High prolactin from frequent suckling suppresses pulsatile GnRH release from the hypothalamus
• Without GnRH pulses, the anterior pituitary cannot produce adequate LH surges
• Without the LH surge, no ovulation occurs

When protection ends:

• If menses returns, feeding intervals exceed 4 hours by day or 6 hours at night, breastfeeding is no longer full/nearly full, or the infant reaches 6 months, another contraceptive method is needed ^[15].
• Ovulation can precede the first recognised menstrual period, so amenorrhoea without the other two criteria is insufficient.

Early and frequent suckling, correct positioning, avoid artificial teats, avoid fatigue and anxiety ^[1]

• Early suckling: ideally within 1 hour of birth (skin-to-skin contact per WHO Step 4)
• Frequent suckling: drives prolactin reflex → more milk production. Typically 8–12 feeds/day in the first weeks
• Avoid unnecessary supplementation or artificial teats while breastfeeding is being established, and counsel on their use and risks as BFHI Step 9 states; if supplementation is medically indicated, protect milk supply and choose a safe feeding plan.
• Support rest, comfort and confidence: pain and acute stress can hinder let-down, but difficulties require skilled assessment rather than blame.

Key points of position: ^[1]

• Support baby's whole body with head and body in a line
• Baby close to mother
• Support the whole body
• Nose to nipple

The illustrated positions are laid-back, transitional/cross-cradle, side-lying, and underarm (football hold). Whichever is used, keep the infant's face, chest, and knees facing the same direction, hold the infant close with the head slightly extended, and support the whole body ^[1].

Key points of attachment: ^[1]

• Chin leads (baby approaches breast chin-first)
• Wide open mouth
• Bottom lip touches breast well away from base of nipple
• Nipple towards rear of roof of mouth
• Cheeks are round during suckling (not dimpled/sucked in)

Additional visual checks are that the chin touches the breast, the lower lip is everted, more areola is taken into the mouth from below than above, and feeding is not painful ^[1].

How to read the two slide diagrams: the useful contrast is deep versus nipple-only attachment. The older labels "whole areola" and "tongue presses the milk ducts/lactiferous sinuses" are anatomically too literal. Areolar size varies, and modern imaging does not support a large subareolar milk sinus ^[17]. Assess comfort, swallowing, milk transfer, output and growth—not areola coverage alone.

The slide's visual pattern is high yield: gradual onset around days 3–5, bilateral and generalised ^[1]. The breast may be firm, warm and painful because both milk volume and interstitial vascular oedema rise.

Current practical management ^[16]:

• Check positioning, attachment and milk transfer; feed according to infant cues.
• If the areola is too tense to latch, use reverse-pressure softening and hand express or pump only a small volume for comfort/attachment.
• Use cold packs and a compatible analgesic/anti-inflammatory such as ibuprofen when appropriate.
• Avoid repeated “pumping to empty,” which drives oversupply and can worsen oedema.

Exam bridge — 2025 MCQ Q9: among the options given, expressing milk is the correct answer for early breast fullness/tenderness; formula, cabergoline and antibiotics are inappropriate ^[9]. In practice, express enough to restore comfort and latch rather than repeatedly emptying the breast.

The deck describes a localised tender lump without systemic illness ^[1]. Modern interpretation is microscopic ductal inflammation/narrowing plus surrounding oedema, not a discrete milk clot that must be forced out ^[16].

• Continue normal, on-demand feeding; the infant's usual intake is the target.
• Use ice and an NSAID if not contraindicated; rest and supportive care.
• Do not use deep massage, vibration, forceful squeezing, repeated hot compresses or extra pumping. These can traumatise tissue, increase production and worsen inflammation.
• Gentle lymphatic-style sweeping may be used for oedema; changing position can improve comfort but does not mechanically “aim suction” at a plug.

Increasing segmental erythema, oedema and pain with fever, chills or tachycardia is inflammatory mastitis; systemic inflammatory features do not by themselves prove bacterial infection ^[16]. Bacterial mastitis is a progression that warrants antimicrobial treatment.

Shared management:

• Support continued breastfeeding; milk from a breast with bacterial mastitis is safe for the infant ^[16]. Feed physiologically rather than trying to “empty” the breast.
• Ice, compatible NSAID/analgesia, rest, hydration to thirst and skilled lactation review.
• If severe retroareolar oedema prevents any transfer, temporarily feed from the other side and return to the affected breast as swelling settles; avoid repeated traumatic attempts.
• Reassess promptly if the patient is systemically unwell or deteriorating.

Antibiotics and cultures:

• Reserve antibiotics for bacterial mastitis rather than uncomplicated ductal inflammation. First-line examples are dicloxacillin/flucloxacillin 500 mg four times daily for 10–14 days or cephalexin 500 mg four times daily for 10–14 days, adjusted to local guidance and allergy history ^[16].
• Plain amoxicillin and erythromycin, although listed in the older slide, are not reliable modern empiric anti-staphylococcal choices.
• If there is no symptomatic improvement after 48 hours of first-line treatment, obtain milk culture and assess for MRSA/resistant or less common organisms. Earlier culture is reasonable for recurrent disease, high-MRSA-risk settings or milk intended for an immunocompromised infant ^[16].
• Second-line options in the ABM protocol include clindamycin or trimethoprim–sulfamethoxazole; the latter needs caution in premature, jaundiced, very young or G6PD-deficient infants ^[16].

Suspect a collection when focal symptoms persist or worsen despite appropriate treatment. Confirm with ultrasound, then achieve source control ^[16].

• Send aspirated material for culture and sensitivity.
• Needle aspiration is often first-line, but repeated aspiration may be needed; catheter/drain placement can provide more definitive management. Incision and drainage remains an option where percutaneous drainage is unsuitable or unsuccessful.
• Continue breastfeeding from the affected breast where feasible; position the infant so the mouth does not contact purulent drainage or the drain/incision. Continue the unaffected side.
• Treat bacterial infection according to culture/local susceptibility and ensure interval clinical or imaging follow-up until resolution.

Drug → Maternal gut/liver (oral bioavailability varies) → Maternal plasma (concentration varies) → Milk (non-protein-bound drugs can pass) → Infant gut (oral bioavailability varies) → Infant plasma (usually very low level) ^[1]

This staircase diagram explains why drug present in milk is not the same as clinically important infant exposure:

1. Maternal oral bioavailability: only a fraction of the oral dose reaches maternal plasma
2. Protein binding: only unbound (free) drug can cross into milk
3. Milk transfer: lipid solubility, molecular size, ionisation, half-life and the milk-to-plasma ratio influence the milk concentration
4. Infant intake and oral bioavailability: exposure depends on milk volume and whether the drug survives and is absorbed from the infant gut
5. Infant handling: prematurity, neonatal age, illness and immature renal/hepatic clearance increase vulnerability

Only use medication when needed ^[1] Medications that can be used in infants are safe ^[1] Medications safe for pregnancy may NOT be safe for lactation ^[1]

Anti-cancer and anti-metabolic drugs should NOT be given ^[1]

These are slide heuristics, not stand-alone prescribing rules. Direct paediatric use at an age-appropriate dose is reassuring, but it does not automatically prove safety for a premature or medically fragile neonate. Likewise, many—though not every—cytotoxic antineoplastic/antimetabolite regimens require interruption; check the exact drug and the post-dose interval in a current lactation reference ^[18].

1. Confirm that the drug is needed and choose the best-studied effective option; do not undertreat serious maternal illness.
2. Check maternal dose/route/duration, infant age and gestation, proportion of milk feeds, expected RID, oral absorption, half-life, active metabolites, toxicity and possible effect on milk supply ^[18][19].
3. Decide whether the plan is compatible, needs infant observation/laboratory monitoring, requires temporary interruption, or needs an alternative drug.
4. Give a specific feeding/expressing plan if interruption is necessary; “pump and dump” is not a universal solution.

The final reference slide points to LactMed (free NIH database), UKDILAS/SPS, and Hale's Medications & Mothers' Milk ^[1]. LactMed provides milk and infant blood levels, reported infant effects, effects on lactation and suggested alternatives, with referenced peer review ^[18].