Main Content Main Naigation
Need Emergency help? Click here
I am a:


Top angle image

If you’re starting your period for the first time, it can bring up a lot of questions. Get the information and advice you need on what’s happening and what to do if you’re worried. 

Most girls will start their periods around the age of 12, which is the time you change from primary school to secondary school, but some girls start their period as early as 8 or as late as 15. You will start noticing some changes in your body, usually about 1-2 years before the start of your periods. You will grow taller, have hair under your arms and pubic area, you might develop spots or acne, and start having breast development. 

The length of time between you being on your period is known as the menstrual cycle, and this is different for most women, but the average is to have a period every 28 days. Regular menstrual cycles that are longer or shorter than this, for example 23 to 35 days, are normal too. 

background squares

Things to know about your period: 

It’s good to be prepared for your period in case it starts unexpectedly. 

You might feel confused or embarrassed, but there is nothing to be ashamed of. 

Your period will usually come once a month, but it can be irregular when you first start. 

You can talk to a relative or another adult you trust about what’s going on.

speech boxoverlay image

Periods: Just the facts:

  • What are periods? Periods are part of the menstrual cycle where you will bleed from your vagina for a few days. 
  • Why do I have periods? During puberty, your female reproductive organs start to develop. Each month, these hormones cause an egg to mature and be released from your ovaries. In case the egg is fertilised by a sperm, the lining of your uterus becomes thick and soft with blood and tissue. If the egg isn’t fertilised by a sperm, this lining of the uterus isn’t needed so comes away and is released from the body through your vagina – this is your period. 
  • When will they start? Females usually have their first period between the ages of 9 and 14. They will probably be irregular at first, but will settle into a pattern after a few months. If you haven’t started your period by the age of 16, talk to your GP. 
  • How often will I have my period? Most females will have their period every 28 days or so. The menstrual cycle normally lasts about 28 days, which means there are 28 days between the start of your period and the start of the next one. It’s very common for periods to be more or less frequent than this though. 
  • How long will it last? Your period can last between three and eight days, on average they last for about 5 days. The bleeding will be heaviest in the first couple of days before it starts to slow down towards the end of your period. 
  • What sanitary products can I use? Sanitary products are used to soak up or collect the blood you release during your period. The main types of sanitary products are: sanitary pads, tampons, period pants and menstrual cups.

For further support and information... 

These links take you to other websites or services that are not provided by Teen Health. The pages have been selected to give you more information on this topic area. They will open another tab in your browser.   
Health for Teens

Health for Teens

Just the facts: periods

Read more
ChildLine logo


Information and advice on periods

Read more

BBC Bitesize

Changes that occur during the menstrual cycle

Read more

BBC Bitesize

Why we should all be talking periods

Read more


A Newsround special on periods

Read more
tellmi logo


Tellmi is a safe, anonymous app where you can talk about absolutely anything 

Read more
Teen Health Logo

Teen Health

Use the link on this page to contact Teen Health 

Read more
Close icon
Close icon
Close icon