How does the placenta prepare the breasts for milk production?

The placenta prepares the breasts for milk production primarily through the release of estrogen. Estrogen plays a crucial role in the development of mammary glands during pregnancy. It stimulates the growth and branching of the ductal system within the breast, enhancing the tissue's ability to produce milk after childbirth.

Additionally, estrogen works in conjunction with other hormones, such as progesterone, which contributes to the development of alveoli, the milk-producing glands in the breast. The combined action of these hormones ensures that the breast tissue is fully developed and ready for lactation once the baby is born.

While testosterone and progesterone are involved in various reproductive processes, testosterone is not typically associated with breast development, and although maintaining progesterone levels is important for pregnancy, it is not the primary mechanism through which the placenta prepares the breasts for milk production. Furthermore, milk production does not happen until after delivery, which is not the role of the placenta. Therefore, the release of estrogen is the key process that facilitates the necessary changes in the breast tissue in preparation for milk production.