Puberty for girls

Puberty is a series of changes that your body goes through as you grow. These changes start between the ages of 8 years to 16 years of age.

Changes to your body will happen over time, and the speed of change will be different for each person. It’s normal for people to start developing at different times so try not to compare yourself to other people the whole time.

Your body starts to produce hormones which will change your body and can also affect your emotions. Getting used to all the changes can sometimes be stressful. You might feel like you can’t control your feelings, like feeling happy or positive one minute and irritable, grumpy or tearful the next.

Here are some of the physical changes that will happen during puberty:

  • You will grow taller
  • Your nipples and breasts will start to swell and fill out
  • Your body shape may grow more rounded and curvy and your hips may become broader
  • Hair will grow under your arms, on your legs and genitals
  • You may get spots
  • The sweat glands under your arms and between your legs will become more active
  • Your hair may get more greasy
  • Your periods will start.


Periods are a natural thing, and they happen to women and girls once a month. It is a normal part of growing up for most girls. During your period, you’ll lose a small amount of blood from your vagina. It’s nothing to be scared of, and it only will last for a few days.

You’ll get your period about once a month, and it’ll last between 3 and 8 days. You might have a stomach ache before or during your period, so ask your parent or carer about a hot water bottle or your usual painkillers to help the pain.

You can use sanitary pads, tampons or menstrual cups to collect the blood. If you don’t have one to hand when your period starts, you can put some tissue or toilet paper in your underwear until you can get one to use.

Sometimes periods aren’t regular, especially when they first start, and it might be difficult to plan exactly when you’ll get your period.

Period pain and mood changes

Throughout your period, you have different levels of hormones in your body. It’s natural to have some side effects from this. A good way to help is to undertake gentle exercise, you could use a hot water bottle to help ease the pain or take a bath or taking some pain relief tablets such as paracetamol can help

Why do periods happen

Periods are part of your menstrual cycle, which is all about your fertility and your body preparing for the possibility to be able to become pregnant. Each month, one of your ovaries (you have 2) releases an egg. The egg travels down 1 of 2 tubes called fallopian tubes and into your womb. The lining of your womb thickens for a short while during this time. If the egg is fertilised by sperm from a boy’s body, it will stick in this lining and grow. This is how you get pregnant. If the egg is not fertilised, then the lining of the womb breaks down and passes out of your body through your vagina as a small amount of blood.

Talking about periods can sometimes feel embarrassing. Remember that almost all women will have had periods, and they will remember what it was like the first time. You could try talking to your mum, aunt or another family member. Talking to friends can sometimes be helpful too.