Your breasts change over the course of your lifetime. These changes relate to a number of factors including age, hormones, medical conditions and lifestyle.
Breasts can keep developing and changing shape up to the age of 18, though many girls’ breasts tend to stop growing around two years after they have their first period, as puberty slows down. However, the full process can take four or five years.
The chest starts to develop a couple of years before the start of menstruation, and may not happen in a uniform way – one breast may begin to appear as long as six months before the other, and may continue to grow at different rates. It’s not uncommon for one to be larger than the other after they stop growing.