Girls usually start their periods between 10 and 16 years of age. Most girls get their first period around 12 years of age.
But everyone develops at different rates. There's no right or wrong age to start having periods.
Your periods will start when your body is ready. This is usually about 2 years after the first signs of puberty appear. In girls, the first signs of puberty are usually breasts beginning to develop and pubic hair starting to grow.
When to contact your GP
Non-urgent advice: Contact your GP if you have not:
- developed any signs of puberty at all by the age of 14
- started your periods by the time you're 16
Your GP can check if you're going through the normal stages of puberty.
Your GP may tell you to 'wait and see'. Often your periods will start naturally by the time you're 18.
Your GP may recommend having blood tests to check your hormone levels. They may refer you to a specialist. This is usually a gynaecologist, a specialist in women's health. Your gynaecologist will try to find the cause and can recommend treatment.
Causes of periods not starting
Causes of periods not starting include:
- a normal delay in development – this often runs in families. So if your mum or sister started their periods late, this may be why your first period is delayed
- a hormonal imbalance
- being underweight
- doing a lot of exercise – this can affect girls who do lots of athletics, gymnastics or dance
- eating disorders
- severe stress
- pregnancy – it's possible to get pregnant before you get your first period, your ovaries can start releasing eggs a few months before your periods start
- a problem with the ovaries, womb or vagina
Treating delayed periods
Treatment for delayed periods depends on what's causing the problem.
Your GP or gynaecologist may recommend hormone therapy if the cause is a hormonal imbalance.
If an eating disorder is the cause, treatment can be therapy and advice about your diet.
If your GP thinks it is caused by doing a lot of exercise, they may recommend doing less. If you're underweight, they may recommend increasing your calorie intake.
If the cause cannot be treated, your GP may recommend therapy or counselling.
Content supplied by the NHS and adapted for Ireland by the HSE