Girls usually start their periods between 10 and 16 years of age. Most girls get their first period when they're around 12.
But everyone develops at different rates, so there's no right or wrong age to start having periods.
Your periods will start when your body is ready. This is usually about two years after the first signs of puberty appear. In girls, the first signs of puberty tend to be breasts beginning to develop and pubic hair starting to grow.
This page covers:
When to see your doctor
You should see your doctor if you haven't started your periods by the time you're 16. Your doctor can assess whether you're going through the normal stages of puberty.
It's also a good idea to see your doctor if you haven't developed any signs of puberty at all by the age of 14.
You may be advised to "wait and see". In many cases your periods will start naturally by the time you’re 18.
Your doctor may recommend having blood tests to check the levels of a number of different hormones.
You may be referred to a specialist (usually a gynaecologist – a specialist in women's health). They'll try to establish the cause and will be able to recommend any appropriate treatment.
The medical name for periods that haven't started by the expected age is primary amenorrhoea.
Possible causes of periods not starting include:
It depends on what's causing the problem.
Hormone therapy may be recommended if the cause is a hormonal imbalance.
If the underlying cause is an eating disorder, treatment will often involve a combination of therapy and advice about your diet.
If too much exercise is thought to be the cause, you may be advised to do less and, if you're underweight, to increase your calorie intake.
If the underlying cause for your lack of periods can’t be treated, you should be able to get NHS therapy or counselling to help you come to terms with what this means for you.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.