Irregular Periods

NHS

Irregular periods are not usually a sign of a problem. But speak to a GP if your periods are irregular or your normal pattern of periods changes.

Check if you have irregular periods

The average gap between periods starting (the menstrual cycle) is 28 days. It can sometimes be a bit shorter or longer. A woman's periods are irregular if the gap between them is less than 21 days or more than 35 days. Irregular periods can affect anyone who has periods. It's more likely for your periods to be irregular when they first start during puberty, and when you're nearing menopause.

Keeping track of your periods

Using an app or a diary to keep track of your periods can help you see if they're irregular. Day 1 of your menstrual cycle is the first day of your period. The last day of your cycle is the day before your next period.

Causes of irregular periods

Common causes of irregular periods include:

  • puberty, when you start your periods
  • the start of menopause (usually between the ages of 45 and 55)
  • pregnancy – a missed period is often an early sign of pregnancy
  • hormonal contraception like the progestogen-only pill, contraceptive injection and intrauterine system (IUS)
  • losing or gaining a lot of weight
  • stress and anxiety
  • exercising too much

Sometimes, conditions like polycystic ovary syndrome (PCOS) and an underactive thyroid gland can cause irregular periods.

Treatments for irregular periods

Treatment is not always needed for irregular periods. The GP may refer you to a specialist (gynaecologist) if you need tests to find out what's causing your irregular periods. If treatment is needed it will depend on the cause.

For example, if a condition like polycystic ovary syndrome is causing irregular periods, the combined pill may help make your periods more regular.

Trying for a baby

Getting pregnant can be more difficult if you have irregular periods because you might not release an egg (ovulate) regularly. It can help to have sex every 2 or 3 days throughout your cycle without using contraception. If you're struggling to get pregnant, hormone medicine or fertility treatment may be recommended.

Useful resources

This Teachers' Maternity Leave Scheme has been updated to reflect the rules concerning...
EA is committed to ensuring that all individuals are treated fairly and with dignity and...
Cancer Focus NI can provide a wide range of presentations to meet the needs of your...
Sometimes when faced with an unplanned or crisis pregnancy it is difficult to discuss it...
This programme is a six week training programme for groups of adults and focuses on...
The Menopause Project is an education and research project between Informing Choices NI...
We all have good and bad days but what and when we eat can influence our mood, energy,...
There are a number of health campaigns throughout the year to raise awareness of...
Around one in five women will experience a mental health issue during pregnancy or within...
Cancer Focus NI, Keeping Well vans are mobile drop-in units which bring health checks,...
This includes: Raising awareness of depression and Aware NI services at a wide range of...
We are delighted to provide this FREE digital toolkit. Designed in partnership with the...
Affected by breast cancer? Join this group to share experiences and ask questions to...
Support for breast cancer
Guided meditations
Learn to manage negative thoughts and look at problems differently
Food diary, exercise tracker and diet coach
Support hub for mothers
Track your treatment and wellbeing
Pregnancy and guidance for after birth
The availability of free period products in public spaces has been increasing owing to...
Active 10 is a free and easy to use walking app that tracks your walking and shows you...
It’s an easy to follow programme known the world over, and perfect for those new to...
Guided meditations
Handle stress and anxiety on the go
This short test will help you understand how heavy your periods are, and point you in the right direction for treatment options.
Your Mind Plan offers practical ideas and advice to help you boost and maintain your mental wellbeing. Answer the quick 5-question quiz and the Every Mind Matters widget will give you 5 tailored actions to help you feel more in control, improve your sleep, deal with stress and anxiety, and boost your mood – as well as the option to easily swap any actions and to save the whole plan via email.

Articles & Videos

Helplines & Web Chats

Informing Choices NI - Helpline
Royal Osteoporosis Society - Helpline
Macmillan - Forum
Macmillan - Ask an expert
Women's Aid - Forum
Association for Post-Natal Illness Helpline
Women's Aid - Domestic abuse helpline