Lactogenesis - The transition from pregnancy to lactation

The most critical time in the establishment of lactation is during the tran sition from pregnancy to lactation, often termed lactogenesis stage II. Thi s transition consists of all orderly set of changes in the mammary,oland th at result in an immediate decrease in the sodium and chloride content of th e mammary secretion product, the secretion of scant amounts of a fluid high in immunoglobulins and other protective substances during the first 2 days post partum, and an increase in the volume of a product with a composition resembling true milk secreted usually starting about 40 hours post partum. These changes are triggered by the fall in progesterone, and possibly estr ogen, following parturition and require high levels of plasma prolactin. Th e role of milk removal in this process is unclear and prospective clinical studies are needed to assess this important parameter.