Final answer:
Breast milk changes from colostrum in the first days postpartum to transitional milk and then to mature milk, offering the newborn tailored nutrition. Foremilk quenches thirst and the richer hindmilk satisfies hunger during feedings.
Step-by-step explanation:
The composition of breast milk changes significantly during the initial days of lactation and over the course of a single feeding to meet the evolving nutritional needs of the newborn. Initially, the mother produces colostrum, a milk rich in immunoglobulins which boosts the newborn's immune defenses and aids in expelling meconium, the early stool, from the infant's digestive system. Closer to approximately four to five days after birth, the colostrum transitions into what is known as transitional milk and eventually matures into what is referred to as mature breast milk. Mature milk consists of foremilk, which is watery and quenches the infant's thirst, followed by hindmilk, which is richer in fat content and provides satiety.