Page 3 of 32
OG17.1 | Physiology of Lactation and BFHI — SDL Guide (Part 3)
Clinical Implications: Supporting, Inhibiting, and Contraindications to Breastfeeding
A working knowledge of the factors that support or inhibit lactation — and of the clinical situations that require modification or cessation of breastfeeding — is essential for postnatal counselling.
Factors that support lactation:
Frequent, effective suckling is the single most important determinant of milk supply. Positioning and attachment are critical — a well-latched infant who takes a large mouthful of areolar tissue applies effective peristaltic pressure with the tongue, stimulating both the prolactin and oxytocin reflexes maximally. Skin-to-skin contact (kangaroo mother care) increases oxytocin in both mother and infant and regulates neonatal temperature and cortisol. Maternal nutrition (an additional 500 kcal/day is recommended), hydration, adequate rest, and psychological support all contribute. Some women experience genuine hypogalactia despite optimal technique; in this setting, a galactagogue (a drug that promotes lactation) may be prescribed. The most evidence-supported galactagogues in current use are domperidone (a dopamine antagonist that raises prolactin by blocking the inhibitory dopamine pathway) and metoclopramide (a second choice due to its central nervous system side effects).
Drugs that inhibit lactation (lactation suppressants):
Historically, bromocriptine (a dopamine agonist) was used to suppress lactation pharmacologically, for instance after stillbirth or when breastfeeding is contraindicated. However, bromocriptine has been associated with serious adverse effects (hypertension, stroke, seizure) and is no longer recommended for routine lactation suppression. Cabergoline (a longer-acting dopamine agonist) is the current recommended agent where pharmacological suppression is clinically indicated. Oestrogen-containing oral contraceptives can suppress milk production and should be deferred until lactation is fully established or avoided altogether in breastfeeding mothers; progestogen-only methods are preferred. Certain antipsychotics (haloperidol, risperidone) raise prolactin and may paradoxically over-stimulate galactopoiesis.
Absolute contraindications to breastfeeding:
The situations in which breastfeeding is contraindicated include:
- Maternal HIV infection where safer feeding alternatives are available (WHO guidelines; in resource-poor settings where formula is unsafe, this balance changes).
- Active untreated pulmonary tuberculosis (until the mother has been on effective treatment for at least 2 weeks and is no longer infectious).
- Infant with classical galactosaemia (inability to metabolise galactose, a lactose component).
- Certain maternal medications that are contraindicated in breastfeeding — notably cytotoxic drugs (methotrexate, cyclophosphamide), radioiodine therapy, and some antiretrovirals. (The LactMed database provides up-to-date guidance.)
- Maternal illicit drug use (heroin, cocaine) — infant exposed via milk.
Relative considerations: Hepatitis B infection is NOT a contraindication to breastfeeding if the neonate receives hepatitis B immunoglobulin and vaccination at birth. Hepatitis C is not a contraindication unless nipples are cracked and bleeding. CMV seropositivity in the mother is generally not a contraindication in term infants (term infants have partial maternal antibody protection); it may be a concern in very preterm infants.
| Indication | Drug | Mechanism | Notes |
|---|---|---|---|
| Galactagogue (hypogalactia) | Domperidone | Dopamine antagonist → raises prolactin | Preferred; minimal CNS penetration |
| Galactagogue (second choice) | Metoclopramide | Dopamine antagonist → raises prolactin | CNS side effects limit use |
| Lactation suppression | Cabergoline | Dopamine agonist → lowers prolactin | Preferred over bromocriptine |
| (Avoid) Lactation suppression | Bromocriptine | Dopamine agonist | Withdrawn from routine use — cardiovascular risk |
SELF-CHECK
A lactating mother on postpartum day 5 is stressed and unable to let milk down despite the baby latching well. Which hormone's release is most likely being inhibited by her psychological stress?
A. Prolactin from the anterior pituitary
B. Oxytocin from the posterior pituitary
C. Human placental lactogen from the placenta
D. Progesterone from the corpus luteum
Reveal Answer
Answer: B. Oxytocin from the posterior pituitary
The let-down (milk-ejection) reflex depends on oxytocin released from the posterior pituitary in response to suckling. Psychological stress activates the sympathetic system, releasing adrenaline which causes vasoconstriction and directly inhibits myoepithelial cell contraction. Prolactin (anterior pituitary, responsible for milk synthesis) is less immediately affected by acute stress. The practical implication is that creating a calm, private, supported environment dramatically improves let-down.
SELF-CHECK
Which of the following is the PRIMARY reason for recommending that a breastfeeding mother on a progestogen-only contraceptive pill is preferred over a combined oral contraceptive pill?
A. Combined pills raise prolactin levels and cause over-galactopoiesis
B. The oestrogen component of combined pills suppresses milk production
C. Progestogens are teratogenic if the infant ingests them via milk
D. Combined pills cause galactosaemia in the breastfed infant
Reveal Answer
Answer: B. The oestrogen component of combined pills suppresses milk production
Oestrogen in combined oral contraceptive pills suppresses milk synthesis. Progestogen-only pills (mini-pill, e.g. norethisterone) do not significantly affect milk supply and are the preferred hormonal contraceptive method while breastfeeding. WHO MEC classifies COCs as category 3 (risks outweigh benefits) within the first 6 months postpartum in breastfeeding women.
CLINICAL PEARL
Retained placental fragment delays lactogenesis II. If a mother on postpartum day 3–4 has no significant milk coming in despite frequent, effective breastfeeding, consider a retained placental fragment as a cause — circulating progesterone from retained placental tissue continues to block prolactin action at the alveolar cell. Ultrasound of the uterus may confirm the diagnosis; surgical evacuation restores the hormonal milieu and milk typically appears within 24–48 hours thereafter. This is a reversible cause of apparent lactation failure that should not be missed.
Self-Assessment: Integrating Lactation Physiology and Clinical Practice
Having worked through the physiology of lactation and the evidence base for the BFHI, this section consolidates your understanding by asking you to apply core concepts to clinical scenarios. The questions below represent the type of reasoning expected in viva voce and written examinations at the final MBBS level. As you attempt each question, consider not only the correct answer but also the underlying mechanism — final MBBS examinations increasingly test explanatory understanding rather than simple recall of isolated facts. The ability to trace a clinical observation back to its hormonal, cellular, or neuroendocrine basis distinguishes a competent clinician from one who has only memorised information. Apply the lactation physiology framework — mammogenesis, lactogenesis I and II, galactopoiesis, the oxytocin reflex, and milk composition changes — to each of the scenarios below before checking your reasoning against the module content.
Key self-assessment questions to work through:
- A woman delivers at 28 weeks gestation. Her milk comes in on day 3 postpartum. Is this expected, and what mechanisms drive this? What specific challenges exist for preterm milk and how does the BFHI address them?
- A woman on treatment for tuberculosis asks if she can breastfeed. She is 2 weeks into four-drug therapy and is no longer sputum-positive. What is your advice, and what is the physiological basis for your decision?
- A multipara on day 5 postpartum complains of bilateral breast engorgement, fever to 37.8°C, and difficulty with feeding. Outline the differential diagnosis, the role of effective milk removal, and when to escalate.
- A hospital administrator asks you to justify the cost of implementing BFHI. Using lactation physiology, health economics, and epidemiological evidence, construct a brief argument for three of the 10 Steps.
Review the BFHI 10 Steps against the physiology covered in this module and ensure you can explain the mechanistic rationale for each step before proceeding to the assessment questions embedded in this SDL.