development of the breast

Last reviewed 04/2023

The breasts develop as follows:

  • stage 1: prepubertal projection of nipple
  • stage 2: the breast bud
  • stage 3: similar to a small adult breast
  • stage 4: the areolar and nipple stand proud of the breast
  • stage 5: the nipple and breast have the same contour

Breasts appear at the start of puberty from 9 to 13 years. Breast development is complete by the end of puberty, after 1.5 to 6 years.

These stages are written in notes preceded with a B, ie B1, B2 etc.

Oestrogen-17beta is the main hormone determining breast development. In addition, progesterone is involved in the promotion of alveolar development.