The primary driver of breast growth is estrogen, a hormone produced by the ovaries.
When the ovaries begin producing estrogen, fat deposits accumulate in the connective tissue within the breasts, leading to enlargement. This process often coincides with the onset of puberty, marked by the appearance of pubic and armpit hair. Estrogen also stimulates the growth of the duct system within the breasts.
Therefore, the increase in breast size is mainly attributed to:
- Fat Deposition: Estrogen signals the body to store fat in the breast tissue.
- Duct System Growth: Estrogen stimulates the development of milk ducts.
