Breast development:

What can adolescent girls expect?

Just as sure as every girl will begin her period one day, her breasts will develop. And just like the start of the period, breast development progresses at different ages among different girls.

Breasts are very individual – they will grow to different sizes and shapes, which is why some girls will develop very large breasts, while others will have much smaller breasts, even once they have fully developed.

It doesn’t matter what size or shape breasts you have. Size really doesn’t matter! After all, breasts are there to play an important role for girls when they grow up and have babies. Breasts consist of milk glands and milk ducts (together with fat and connective tissue) to provide milk for babies. The size and shape of the breast makes no difference for this role.

Still, not all girls are happy with the development of their breasts. Some wish they had smaller breasts, while others worry that their breasts aren’t developing as quickly as they should. This is nature, and it’s all normal.

That’s why it’s so important to find a bra that best suits your size – whether that’s 32AA or 36C – and to feel confident and happy wearing that bra.

Development stages

There are no hard and fast rules when it comes to ages – some girls’ breasts start growing as young as age 8, while others may wait until they are at least 14 – but there are defined stages of breast development.

Some years ago a British paediatrician named James Mourilyan Tanner invented the ‘Tanner stages’ (also known as the Tanner Scale) to reflect the physical development of adolescents. For breasts among girls, he identified five stages, which show how the breast grows during a girl’s adolescent years.

Most girls reach stage 5 by the time they are 18 years old, but they may get there as young as 14 or 15.

• Stage 1 (usually under 10 years old). The development of the breasts is not yet seen. The areola, which is the darker skin of the breast surrounding the nipple, is just a brownish spot
• Stage 2. The breast buds – the small bumps behind the nipple – begin to form, in preparation for growth of the milk ducts and a very small mound can now be seen. The areola starts to widen
• Stage 3. Now the breasts are beginning to noticeably enlarge. They start to become wider and fuller. The areola also continues to widen
• Stage 4. The breasts are now forming mounds. The areola now also has its own mound, which projects from the breasts
• Stage 5. The breasts reach their full adult size. Except for changes that can affect the size of the breasts, such as pregnancy and weight gain, a girl’s breasts are likely to remain this size during her adult life.

It is also worth remembering that sometimes breasts do not develop evenly, and one breast may be a little bigger than the other. This is perfectly normal and healthy, and once the breasts have fully developed they will most likely be even.