IBCLC Practice Exam 2026 – Complete Preparation Guide

During Lactogenesis II, there is a significant transformation in the composition of breast milk as it transitions from colostrum to mature milk. One of the key changes involves an increase in both lactose and lipid content. Lactose, which is vital for providing energy and supporting the growth of beneficial bacteria in a baby's gut, sees a rise as the body prepares to meet the nutritional needs of the growing infant. At the same time, lipids (fats) also increase, providing essential fatty acids and bolstering the caloric value of the milk, which is important for infant growth and development.

As for sodium and protein, these components often decrease during this stage, while the proportions of carbohydrates and fats adapt to better support the infant's nutritional requirements. This balance is crucial, ensuring that the milk becomes more suited for daily feeding and overall nourishment. The dynamic shifts in these components reflect the body's response to the baby’s needs, signifying the move toward a more mature milk stage that supports the infant's growth effectively.