Final answer:
A woman who suddenly stops breastfeeding may experience breast engorgement and leakage because her body continues to produce milk due to the established positive feedback loop, based on previous breastfeeding demand, which takes time to adjust after breastfeeding stops.
Step-by-step explanation:
A woman experiencing breast engorgement and leakage after she has suddenly stopped breastfeeding is likely going through this because her body is still producing milk due to the previous demands of breastfeeding. When her infant suckled, sensory nerve fibers in her areola initiated a neuroendocrine reflex, causing milk secretion from the lactocytes into the alveoli. Oxytocin, released by the posterior pituitary, stimulated myoepithelial cells to contract, pushing milk into the lactiferous ducts, lactiferous sinuses, and finally out through the nipple pores.
This process is part of a positive feedback loop, where the infant's suckling leads to more milk production. The sudden cessation of breastfeeding disrupts this loop, yet the body still produces milk for some time, resulting in engorgement and leakage, similar to what happens in the first few weeks after birth. Over time, if not stimulated by feeding, milk production will decrease and engorgement will subside.