In many cases, absent periods aren't a cause for concern. However, sometimes an underlying medical condition can be responsible that will need to be investigated and treated.

Some girls won't start their periods by the expected age, and there are various reasons why periods might naturally stop at certain times.

For example, your periods will stop during pregnancy, while you're breastfeeding, or after the menopause. Some types of contraception can also cause you to temporarily stop having periods.

Underlying medical conditions

The medical name for absent periods is amenorrhoea. The lack of periods can sometimes be a sign of an underlying medical condition, such as:

  • polycystic ovary syndrome (PCOS) – a condition where the ovaries don't regularly release an egg (ovulate)
  • hypothalamic amenorrhoea – where the part of the brain that regulates the menstrual cycle stops working properly; this is thought to be triggered by excessive exercise, excessive weight loss, or stress
  • hyperprolactinaemia – where a person has abnormally high levels of a hormone called prolactin in their blood
  • premature ovarian failure – where the ovaries stop working properly in women who haven't yet reached the age of natural menopause (usually from the age of 50)

Read more about the causes of absent periods.

When to seek medical advice

You should see your GP if you're worried about any problems with your periods so they can try to find the cause.

Depending on what your GP thinks may be causing your absent periods, you may be referred to a specialist for further investigation and any necessary treatment.

Read more about diagnosing absent periods.

Who's affected?

It's relatively common to stop having periods after previously having them. This is known as secondary amenorrhoea, and it's estimated to affect around 1 in 25 women at some point in their lives.

It's more common in teenage girls and younger women, particularly in certain groups, such as professional athletes, dancers and gymnasts.

Not starting your periods by the expected age (primary amenorrhoea) is much less common. It's estimated to affect 1 in every 300 girls.

Treating absent periods

The treatment for absent periods will depend on the cause. For example, PCOS can often be controlled using hormonal treatments, while women with hypothalamic amenorrhoea will often start to have regular periods if they cut down on exercise and reach a healthy weight.

In some cases, your doctors may recommend waiting to see if your periods return or start on their own.

Sometimes it isn't possible for periods to be restored with treatment. This is usually the case with absent periods caused by premature ovarian failure.

Read more about treating absent periods.

The menstrual cycle

Periods are part of the menstrual cycle, which usually starts when a girl is around 12 years old, but it can be earlier or later than this.

Roughly every 28 days, a woman's ovaries will release eggs – as long as she hasn't had the menopause. This is known as ovulation.

The lining of the womb will thicken to prepare for the eggs. If the eggs aren't fertilised by sperm, the thickened lining will break down, resulting in bleeding from the vagina (a period).

Page last reviewed: 06/10/2015

Next review due: 06/10/2017