The initiation of lactation is primarily dependent on which of the following factors?

The initiation of lactation is primarily dependent on a cascade of hormonal changes that occur during and after pregnancy. This complex interplay involves several hormones, including estrogen, progesterone, and prolactin, which gradually prepare the breasts for milk production and secretion. During pregnancy, elevated levels of estrogen and progesterone stimulate the growth and development of milk-producing glands and ducts.

After childbirth, the levels of these hormones drop significantly, which allows prolactin, a key hormone produced by the pituitary gland, to take effect and stimulate milk production. Additionally, the act of the baby nursing triggers further hormonal responses, primarily through a feedback loop that promotes ongoing milk production and ejection.

While early nursing or milk removal plays a significant role in establishing and maintaining lactation and prolactin is crucial for milk production, it is the entire cascade of hormonal changes that fundamentally drive the initiation of lactation after the delivery of the placenta. Maternal hydration does contribute to overall health and the ability to produce milk, but it is not the primary factor influencing the onset of lactation itself.