Center for Young Women's Health

Breast Health


Intro Breast Cancer Risks
What's Normal? Buying a Bra
Lumps & Bumps Measuring for a Bra
Self Breast Exam


  • Breasts come in all shapes and sizes.
  • Although most lumps or changes in your breast are normal when you are a teen, check with your HCP if you have a new lump.
  • A well-fitting bra helps prevent breast discomfort, back pain, and shoulder pain.
Getting Treatment:
The Division of Adolescent/Young Adult Medicine at Boston Children's Hospital offers special services in the diagnosis and treatment of breast health problems.

Women's breasts come in all shapes and sizes. There is no perfect shape or size for breasts. Normal breasts can be large or small, smooth or lumpy, and light or dark.


Your breasts start growing when you begin puberty. During puberty the hormone levels in your body change. This causes your breasts to develop and your periods to start. Lots of things influence when you are going to begin puberty and develop breasts, including heredity (the way certain characteristics are passed down from generation to generation), weight, exercise, nutrition, stress, and chronic illnesses.


How do breasts develop?

The inside of your breasts is made up of fatty tissue and many milk-producing glands, called mammary glands. The dark area of your breast around your nipple is called the areola. As your body starts to develop, a small bump grows under the areola and nipple. This bump is called the breast bud. As the buds get larger and rounder, the breasts grow.


As your breasts develop, the areolae get bigger and darker. Areolae and nipples can range in color from light pink to purplish to light gray depending on your skin color.


When will I get breasts?

Your breasts start growing when you begin puberty. Puberty is the name for the time when your body goes through changes and you begin to go from being a child to an adult. During puberty the hormone levels in your body change, causing your breasts to develop and your menstrual periods to start. Heredity (the way certain characteristics are passed down from generation to generation) and nutrition determine when you are going to begin puberty and develop breasts. Most girls' breasts begin growing when they are about 9 or 10 years old, but some girls may start developing breasts earlier or later than this age.


How long will it take to get breasts?

It takes different people different amounts of time to develop breasts. The age when you start to develop does not have an effect on the final size of your breasts. For example, if you develop earlier than most girls, this doesn't mean that you will have bigger breasts than most girls.


Does everyone develop breasts at the same time?

No. It's normal for some girls to start to develop breasts when they're 7 or 8 years old, while others don't start until they're 12 or 13. Every girl has her own "clock" that her body follows. For example; girls who do gymnastics, dance, track, or some other very active sport may go through puberty at a later age. Even if your development is normal, it can be hard if you seem to be either the first or the last one to develop breasts. Talk to a parent or an adult that you trust and tell him/her how you are feeling. If you develop early, remember that other girls will soon catch up.

It's a good idea to talk with your health care provider if you haven't started any breast development by the time you're 13 years old.


Is there anything I can do to increase the size of my breasts?

Heredity is the most important factor in determining breast shape and size. No creams, special exercises, or clothing will permanently change your breast size. Your breasts may change with weight loss or gain or after a pregnancy, but for the most part the size of your breasts stays the same once you've finished puberty. Also, breast size has no effect on whether a woman will be able to breastfeed her baby.


When and how will my breasts make milk?

Inside a woman's breasts are tiny pockets called alveoli. After a woman gives birth, her brain's hormones tell the alveoli to produce milk. When her baby sucks on her nipple, the sucking draws milk from the alveoli through the milk ducts and out small holes in the nipple. When the mother stops breast-feeding her baby, her alveoli slowly stop making milk.


    Next: What's Normal


Written and reviewed by the CYWH Staff at Boston Children's Hospital


Updated: 2/27/2014

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