Girls’ breasts stop developing around the age of 14-18, marked by the disappearance of the second bulge of the areola, but sometimes affected by race, region and other factors.
Girls’ breast development often mostly begins on the left side and is divided into five stages, ① Before the age of 9, the preparatory stage before puberty. ② Around the age of 11, the breast germ under the nipple begins to grow and the breast bulge is semicircular. ③ Adulting growth of the margins. ④ Breasts enlarge rapidly and nipples and areolas protrude. ⑤ Formation of breasts, nipples and areolas as in adults.
Generally by the age of 18, breast development stops. The sign is that the breasts develop to stage 5 and the second bulge of the areola disappears. Pubic hair has become similar in character and amount to that of an adult, and is distributed in an inverted triangle that reaches the upper thighs. Bone scales have closed and stopped growing, and height has become almost fixed. Menstruation has also become essentially normal.
The time when a girl’s breasts stop developing varies greatly among individuals and is influenced by factors such as race and environment.