Final answer:
The nurse should educate the postpartum client on lactation, which involves the development of the breast's milk-producing structures and the hormonal response to suckling. They should explain the transition from colostrum to transitional milk and then to mature milk, which varies in composition during a feeding from foremilk to hindmilk.
Step-by-step explanation:
The nurse providing discharge teaching to a postpartum client should educate on the process of lactation and the optimal use and storage of breast milk. Lactation is the production and secretion of breast milk, which begins during pregnancy with the development of lactiferous ducts and alveoli in the breast. During lactation, hormonal signals, particularly the release of oxytocin triggered by suckling, cause the milk to be squeezed from the alveoli and drained toward the nipple for the infant to consume.
In the first few days postpartum, the breast produces colostrum, which is rich in immunoglobulins to boost the newborn’s immune system. Transitional milk follows, providing a balance between colostrum and mature milk over the subsequent days. This later shifts to mature milk, which changes in composition from foremilk at the beginning of a feeding (more watery to quench thirst) to hindmilk at the end of a feeding (richer in fat to satisfy hunger).