Factors Causing Breast Changes

Menstruation and Menopause
Estrogen and progesterone cause the growth of milk ducts and stimulation of these milk ducts respectively. The former, according to experts, is increased in the first phase of the menstrual cycle, while the latter is at peak on the second phase of the cycle.
However, during the menopausal stage, the ovaries stop producing these two hormones. Consequently, this causes the breast to stop undergoing the cycle …