Which hormone is essential for milk production?

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

Prolactin is the key hormone responsible for lactogenesis, which is the synthesis and production of milk within the breast's alveolar cells.
It is secreted by the anterior pituitary gland.
After delivery, the sharp decline in estrogen and progesterone levels allows prolactin to act on the breast tissue to initiate milk production.
The suckling stimulus from the infant causes surges in prolactin release, which maintains the milk supply for ongoing breastfeeding.

Option A: Thyroid hormones are supportive of lactation by regulating overall maternal metabolism, but they do not directly stimulate milk production.
Option B: Antidiuretic Hormone (ADH) is involved in water reabsorption by the kidneys and plays no direct role in lactation.
Option C: Oxytocin is essential for the milk 'ejection' or 'let-down' reflex, which moves milk from the alveoli into the ducts, but it does not produce the milk.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of lactation as background academic context rather than a clinical decision trigger.
It is crucial for nurses to educate new mothers on the difference between milk production (prolactin) and milk ejection (oxytocin). This helps them understand that frequent suckling is key to establishing and maintaining a good milk supply.
Understanding this physiology helps in troubleshooting breastfeeding issues. For example, if a mother has adequate milk but the baby isn't getting it, the issue might be with the oxytocin reflex (e.g., due to stress or pain), not with prolactin or milk supply.
What if? If a mother has a condition like Sheehan's syndrome (pituitary necrosis after postpartum hemorrhage), she would be unable to produce milk because of the lack of prolactin secretion. In this case, breastfeeding would not be possible, and alternative feeding methods would be necessary.

How to Approach the Question

First, identify the key phrase in the question: 'essential for milk production'.
Recall the primary hormones involved in lactation: prolactin and oxytocin.
Differentiate their specific roles. Remember the mnemonic: Prolactin = Production; Oxytocin = Out (ejection).
Evaluate the options based on this differentiation. Prolactin is directly responsible for producing milk.
Eliminate the other options. Oxytocin is for ejection, not production. Thyroid and ADH have other primary functions.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 3 p. 69-71

E6 Physiology Essentials Sembulingam 10e Part 2 p. 150-152

E6 Obstetrics Williams p. 48-68

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