Milk Production

Lactogenesis, or milk production, is divided into 3 stages:12

Stage I begins approximately 12 weeks before delivery with a notable increase in circulating pregnancy hormones:

  • Breast size increases as the alveoli begin to fill with colostrum, the rich, nutrient filled, first milk to be expressed after delivery.
  • Blood flow to the breast tissue and diameter of the areola increase.
  • High levels of progesterone prevent full milk production until after birth.

Stage II begins on average 2-3 days after birth when the milk “comes in.”

  • Progesterone levels drop while prolactin levels remain high.
  • Volume of milk produced increases each day.
  • Milk’s composition changes to mature milk, still full of nutrients for the infant’s needs.
  • The breasts produce milk whether a mother is breastfeeding or not.
  • Frequent breastfeeding in the first week after birth increases number of prolactin receptors in the breast.
  • Increased sensitivity to prolactin leads to more milk produced.

Stage III is also known as “galactopoiesis.”

  • Milk production switches from endocrine control to autocrine control.
  • Production becomes more dependent on continual removal of milk from the breasts and less dependent on the circulating hormones.
  • Essentially, the more a mother nurses, the more milk she will produce (Supply and Demand).
  • Milk removal also depends on the quality of an infant’s latch and quantity of suckling.