BREASTFEEDING

Introduction

Physiology of Lactation

Stages of Milk Production

• Estrogen promotes ductal proliferation; progesterone promotes alveolar development.
• High estrogen and progesterone during pregnancy suppress prolactin's lactogenic action.

• Colostrum begins to form in alveoli.

• Delivery of the placenta removes the inhibitory progesterone/estrogen influence.
• Prolactin from the anterior pituitary now acts unopposed on mammary alveoli, triggering copious milk secretion.
• Requires co-support from growth hormone, cortisol, parathyroid hormone, and insulin (for substrate supply).

• With each suckling episode, afferent nipple impulses travel to the hypothalamus, causing a 10-20 fold surge in prolactin lasting ~1 hour - keeping alveoli secreting milk.
• If suckling stops, milk supply fails within ~1 week.
• (Guyton & Hall Textbook of Medical Physiology)

Milk Ejection (Let-Down) Reflex

• Suckling impulses travel via somatic nerves to the hypothalamus, triggering oxytocin release from the posterior pituitary.
• Oxytocin contracts myoepithelial cells surrounding alveoli, ejecting milk into ducts at +10-20 mmHg within 30-60 seconds of suckling.
• Emotional stimuli (hearing the baby cry, fondling) can trigger let-down; conversely, psychogenic stress and sympathetic activation inhibit oxytocin and suppress let-down.
• Suckling on one breast induces milk ejection in the contralateral breast as well.
• (Guyton & Hall Textbook of Medical Physiology)

Prolactin Inhibitory Hormone (Dopamine)

• Dopamine (from arcuate nuclei) is the primary prolactin inhibitory factor.
• Hypothalamic or pituitary damage may increase prolactin (galactorrhea) by removing this inhibition.

Lactational Amenorrhea

• Suckling-induced prolactin surge suppresses GnRH from the hypothalamus, inhibiting the ovarian cycle.
• Provides ~98% contraceptive protection during the first 6 months if: exclusively breastfeeding + amenorrheic + <6 months postpartum (Lactational Amenorrhea Method, LAM).

Composition of Human Milk

Colostrum

• Thick, yellowish fluid secreted for the first 3-5 days.
• Rich in secretory IgA, lactoferrin, white blood cells, growth factors, and protein.
• Lower in fat and lactose than mature milk.
• Acts as a "first vaccine" - coats neonatal gut mucosa, preventing pathogen adherence.

Foremilk vs. Hindmilk

• Foremilk (beginning of feed): watery, high in lactose, quenches thirst.
• Hindmilk (end of feed): richer in fat, provides satiety and calories. Infant should empty one breast before switching to ensure adequate hindmilk intake.

Benefits of Breastfeeding

For the Infant

• Nutritional: perfectly bioavailable; lactose concentration is 50% greater than cow's milk for brain development.
• Immunological: secretory IgA, lysozyme, lactoferrin, macrophages - protect against respiratory tract infections, otitis media, necrotizing enterocolitis (NEC), diarrhea.
• Developmental: associated with higher IQ scores; reduces risk of type 1 DM, obesity, celiac disease, inflammatory bowel disease, and atopic disease.
• Reduces SIDS risk.

For the Mother

• Promotes uterine involution via oxytocin.
• Reduces postpartum bleeding.
• Accelerates return to pre-pregnancy weight.
• Reduces lifetime risk of breast cancer, ovarian cancer, and type 2 diabetes.
• Provides lactational amenorrhea (contraceptive benefit).
• Promotes mother-infant bonding.

Practical Guidelines

Initiation

• Skin-to-skin contact immediately after delivery.
• First feed within 30-60 minutes of birth.
• Feed on demand: 8-12 times per 24 hours (every 2-3 hours).
• Offer both breasts at each feeding; alternate the breast offered first.
• Milk production established in first 2-4 days; dramatic increase day 3-5.
• (Textbook of Family Medicine 9e)

Correct Latch

• Wide-open mouth with everted lips.
• High position on areola (not just nipple).
• Chin touching breast.
• Inadequate latch = lips near base of nipple, small amount of areola in mouth - causes nipple pain and insufficient milk transfer.

Duration

• Exclusive breastfeeding for 6 months.
• Continue with complementary foods until at least 12 months (WHO recommends up to 2 years).

Supplementation

• Vitamin D: 200-400 IU/day from the first 2 months (human milk is deficient in vitamin D - risk of rickets).
• Iron-rich complementary foods from 6 months.
• Water, juice, and glucose water should NOT be given in the first 6 months.

Contraindications to Breastfeeding

Absolute Contraindications

Conditional/Special Situations

• Active HSV lesions on breast: may give expressed milk from unaffected breast.
• Maternal varicella (5 days before to 2 days after delivery): expressed breast milk may be given.
• Methadone/buprenorphine in a stable maintenance program: NOT a contraindication.
• Most maternal medications are compatible with breastfeeding - consult LactMed database.
• In developing countries, WHO recommends breastfeeding even in HIV-positive mothers (if safe, affordable alternatives are unavailable) with antiretroviral coverage.

Common Breastfeeding Problems and Management

WHO Ten Steps to Successful Breastfeeding (Baby-Friendly Hospital Initiative - BFHI)

1. Written breastfeeding policy
2. Train all health care staff
3. Inform all pregnant women about breastfeeding benefits
4. Help initiate breastfeeding within 30-60 minutes of birth
5. Show mothers how to breastfeed and maintain lactation
6. Give no food or water other than breast milk unless medically indicated
7. Practice rooming-in 24 hours a day
8. Encourage breastfeeding on demand
9. Give no artificial teats or pacifiers
10. Foster breastfeeding support groups

Key Points for Exam

• Exclusive breastfeeding for 6 months - then complementary foods with continued BF to 12 months+.
• Prolactin maintains milk secretion; oxytocin drives milk ejection.
• Dopamine is the prolactin inhibitory factor.
• Colostrum = rich in sIgA; critical immunological protection in the first days.
• LAM = 98% effective if all 3 criteria met (<6 months, exclusive BF, amenorrhea).
• Vitamin D supplementation is required for all breastfed infants.
• HIV in developed countries = absolute contraindication. In resource-limited settings = relative (with ART).
• Do NOT stop breastfeeding in mastitis or plugged ducts.