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Breasts - info for girls who are nearly teens

girls; breasts; bra; boobs; puberty;


What are breasts?

Look at any magazine or movie and you will be able to see straight away what breasts are!

  • trying on a braBreasts are two mounds of flesh which grow on the chest of girls as they reach puberty.
  • Inside the breasts are glands which will be able to make milk if a woman has a baby, and also cells containing fat.
  • They feel a bit soft and spongy and start to grow when a girl reaches puberty.
  • As the hormone oestrogen (say eest-tra-jen) begins to circulate round the body, a girl's ovaries start to make hormones and her breasts start to grow.
  • When a woman has a baby, her breasts produce milk to feed her baby. All sizes of breasts can produce milk for the baby.
  • Boys have breasts too, but usually they stay flat. Some boys develop tissue behind their nipples during puberty, but this flattens again when they have reached the end of puberty. Our topic 'Boys' breasts' can tell you more if you are worried.

Growing breasts

Breasts come in many sizes but they all start the same way.


  • At first the breasts start to 'bud' [like a flower] which means that a small bump appears behind each nipple. It is normal for your nipples to feel tender and a bit sore at this time.
  • Next, the nipple and the circle of skin around it [the areola] start to get darker and bigger.
  • Then the rest of the breasts start to grow.
  • At first they may look a bit 'pointy'.
  • As they grow they become rounder and fuller.
  • The size of breasts depends on two things.
    • Your genes. If mum, or your grandmothers, have large breasts then it is likely that you will too.
    • Your weight. If you are overweight then some of that extra fat will go to your breasts.
  • Breasts usually start growing some time between 8 and 13 years and can continue to grow into a girl's early twenties.
  • In your class you may have some girls who are still flat and others who are well developed. It all depends on when you start puberty and your genes.

Buying a bra

Why wear a bra?
No-one needs to wear a bra, but bras protect and support breasts, they help to make you feel comfortable when you are dashing around doing sport, they can help a girl feel good by giving a shape that she likes to her body and they can make a girl feel less self conscious when wearing tee shirts around those 'immature' boys in her class or friendship group.

(Boys can be such a pain sometimes, twanging bra straps and making silly comments - can't they? Make sure that you tell them right away that you do not appreciate their comments, and what they are doing and saying is harassment!)

changing room
So what kind of first bra will you buy?

Sports bras are a great first bra because they are comfortable, they don't dig in anywhere and they hold the breast firmly.

Many tops have a sort of 'built-in' bra so that you may not need to buy a bra at first.

Girls with large breasts may find that underwire bras provide more support.

Getting the right bra

The main thing to know is your bra size.

  • Your bra size has two measurements, one for the size of your chest and one for the size of your breast (cup size) eg. 10A would mean that the chest size is 80cm (32inches) and the cup size is A.
  • I know it could be a bit embarrassing, but it is a good idea to be measured for your first bra by the sales woman in the bra department.
  • If that sounds too-o-o embarrassing then you and mum, or a female carer, can work out your size using a tape measure.

This is what you do
Using a cloth or paper tape measure:

  • Measure round your body under your breasts - have the end of the tape at the front so that you can read it and be careful not to pull too tight or let the tape go too slack.
  • Write down the measurement. This gives your chest size.
    getting the right bra size
  • Now measure right round again, but this time bring the tape over the fullest part of your breast (bust size). Don't pull tight or let the tape go slack.
  • Write down this number and take away the first number to find the cup size that you need.

This chart will help you work out your chest size (under bust).

Size  cm
8 75 30
10 80 32
12 85 34
14 90 36
16 95 38

This chart will help you work out your cup size.

Difference [cm] 0 to 13 15 17 19
Difference [inches]  0 to 6 7  8 9
Cup size AA, A B C D

Here's an example
Chest size:   75 cm [30 inches]
Bust size:     80 cm [32 inches]
Difference:     5 cm [2 inches]
Bra size will be around 8A
This gives you an idea of what size to try.

Wearing a bra

How to put your bra on:

  • Put your arms through the bra straps and lean forward so that the breasts fall into the cups.
  • Fasten the back in the middle hook.
  • Stand up straight and move the breasts with your hands until they fit comfortably into the cup.
  • If the bra feels tight or loose, refasten on a different clip
  • Adjust the straps so that they feel comfortable but not tight.
  • Always try a bra on and make sure that it is comfortable before you buy it. Different styles fit in different ways and breasts are different shapes. You need a bra that fits your shape.
    trying on first bra
  • At first it will seem strange wearing a bra but you will soon get used to it.
  • Wash it often (put it in a washbag to stop it getting tangled up with other clothes if you put it into the washing machine.)
  • Take it off at night.
  • Feel happy that you are growing into a woman.

Answering your questions


  • Why do you have to wear a braquestion mark
    Well you don't. Most women choose to wear a bra to feel comfortable, give a shape they want and to give support to the breasts. Some women choose not to wear a bra, and this does not cause any problems with the health of their breasts.

  • Do all girls get breastsquestion mark
    All girls do get breasts, although some may be small. This can be because of genes, because the girl is a small person or very thin, or because the girl is an athlete and trains hard.

  • What is the stuff that comes out of breasts before the milk comesquestion mark
    When a woman has had a baby, the first fluid is called 'colostrum' and as well as being very good food for the baby, it contains lots of antibodies which protect the baby from disease.

  • developing breastsI'm bigger than most of the girls in my class. I get embarrassed and feel like people are staring at me. What can I doquestion mark
    Don't worry. You have probably developed early and your friends will soon catch up over the next few years. Tell people who are unkind that the word for what they are doing is harassment, and you should tell the teacher about it.
    If you are really worried, go and talk to your doctor. Your doctor can't change the size of your breasts - there are no drugs or hormones that will do that. But if you are feeling unhappy your doctor may be able to help you manage your feelings.

  • Is it normal to have one breast bigger than the otherquestion mark
    It is common for one breast to be different to the other.
    They may be different sizes or shapes. Our bodies may seem to be symmetrical (where one side is exactly the same as the other – only reversed) but they are often not symmetrical. For example one foot may be a different length to another, eyes may be slightly different shapes or colours and it is common for male testes to be different sizes too.
    This is nothing to worry about. Try different types and shapes of bra until you find one that suits your breasts and gives you the look and comfort that you want.

  • Why do long hairs grow around the nipplequestion mark
    It is fairly common for some long straight hairs to grow from the areola [the area of darker skin around the nipple]. This is caused by 'sex' hormones that are traveling around in your body. You will notice that you are getting more hair in other areas of your body too. If you are worried about it go and have a talk with your doctor.

  • Why do my nipples not stick outquestion mark They sort of sink in to my breast.
    This is called an inverted nipple. There is nothing wrong and it should not be a problem even if you want to have a baby who you want to breastfeed.
    In older women, if their nipples normally stick out but they then become inverted, and stay that way, they need to check it out with their doctor.

  • Mum says she checks her breasts every month by looking at them and feeling them to make sure that she has no lumps that could be breast cancer. Should I do the same or wait until I am olderquestion mark 
    Breast cancer is very rare in young women but it is still a good idea to get to know your breasts. Then if there are any changes you can go to see your doctor to find out what is happening.

  • My breasts feel sore sometimes. Is this normalquestion mark 
    Breasts may feel sore when they are starting to develop and before a period. Or it may be that you need a larger bra cup.

Dr Kate says:

Dr Kate"Breasts are signs that girls are developing into women. If you are worried about anything to do with your breasts, the good thing is that every woman knows what it is like to start growing breasts, so you have plenty of people to talk to!
Everyone grows at her own rate so don't worry if everyone else in your class has breasts and you don't - you will in time. If you are really worried then go and have a chat with your doctor."

If you want to know about the changes in your body then look at our topics on Puberty.

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We've provided this information to help you to understand important things about staying healthy and happy. However, if you feel sick or unhappy, it is important to tell your mum or dad, a teacher or another grown-up.


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