Key points
- A period may be ‘heavy’ if it causes a person to lose so much blood that it impacts their daily life. For example, they cancel plans during their period.
- Losing large amounts of blood during a period can cause iron levels to drop.
- Different types of medicine can make periods lighter, including non-hormonal medicines (such as anti-inflammatories and tranexamic acid – a medicine that reduces bleeding) and hormonal medicines (such as the oral contraceptive pill).
- If your young person has heavy periods, they should speak to their doctor about treatments.
What is a heavy period?
Everyone’s menstrual cycle is different, so it is hard to define a heavy period.
A period may be ‘heavy’ if it causes a person to lose so much blood that it impacts their daily life. For example, if they cancel plans during their period because it is too hard to manage, or they bleed so much that they have to get up in the middle
of the night to change their period products.
Doctors will sometimes refer to heavy periods as ‘heavy menstrual bleeding.’
Are my young person’s periods heavier than they should be?
Your young person’s periods may be too heavy if they:
- need to change their period product every one to two hours
- soak through period products during the night, or have to get up to change them
- pass blood clots larger than 3cm (around the size of a 50c coin)
- double-up on period products to stop leakage, like using a tampon and a pad at the same time, or period underwear and a pad.
Losing a lot of blood during a period can cause iron levels to drop. Iron is an important part of the protein ‘haemoglobin,’ which carries oxygen around the body.
If your young person has heavy periods and low iron, they may also:
- Feel tired, dizzy, faint, or breathless
- Have low energy
- Look pale.
What causes heavy periods?
There are many possible causes of heavy periods. The most common in teens and young people are:
- Ovaries and hormones
- Periods can be heavier while the reproductive system is still maturing. It is common for the ovaries to be a bit disorganised for the first few years after periods first begin.
- The ovaries are small organs that release eggs and produce the hormones oestrogen and progesterone. Oestrogen makes the uterus lining grow, while progesterone helps to organise and thin it.
- Stress
- Periods can be heavier during times of stress, as stress affects hormone levels.
- Nutrition and exercise
- Diet and activity level can both impact hormones; therefore, they can also affect the heaviness of periods. A balanced diet, regular physical activity, and a healthy body weight should help to keep periods more regular.
Could a medical condition be causing my young person’s heavy periods?
If you or your young person are worried that a medical condition is causing their heavy periods, they should speak to a doctor. The doctor may ask questions about their symptoms, as well as whether they tend to bruise easily or get blood noses a lot.
These can be signs of a bleeding disorder.
Some things that may affect the heaviness of periods in teens and young people are:
- Mild bleeding disorders
- Losing or gaining weight
- Doing a lot of exercise without enough nutrients in their diet
- Stress
- Medicine like blood thinners.
Supporting your young person with heavy periods
It is important to support your young person if they are managing heavy periods. This will look different for every family; some young people will not want to chat about their periods with their parents, and that is okay. Instead, you could encourage
them to speak with another trusted adult, such as a sports coach or school nurse.
If your young person’s heavy periods are starting to impact their life, it may be time for them to get professional help. For example, if they:
- organise their life around their period
- cancel plans or avoids activities during their period
- cannot sleep properly because they have to wake up to change period products
- have signs and symptoms of low iron that stop them from doing their usual activities – for example, feeling dizzy and not being able to play sports
- worry they may have a medical condition causing their heavy periods
- are upset about how much blood they are losing.
Your young person’s doctor is the best person to share advice on heavy periods. They will ask your young person about their periods, so it is a good idea for your young person to make note of things such as:
- How often they need to change their period products
- Whether they get blood clots bigger than 3cm
- Any other symptoms they have.
The doctor may order some blood tests if they think your young person may have low iron or another underlying condition.
Treatments for heavy periods
If your young person needs treatment for their heavy periods, their doctor is likely to suggest taking some kind of medicine.
The different types of medicine that can make periods lighter are:
- Non-hormonal medicines
- Over-the-counter anti-inflammatory pain medicines like ibuprofen, mefenamic acid, and naproxen can all help to reduce blood flow to the uterus lining. They can also ease period pain.
- Tranexamic acid is a prescription medicine that stops the body from breaking down blood clots too quickly. It does not cause clots.
- Hormonal medicines
- Hormonal contraception like the pill or intrauterine devices (IUDs) can reduce menstrual bleeding.
- They can also use the pill to skip periods.
- There are many contraceptive pills with different hormones; if one does not work for your young person, they can try another.
Common questions about heavy periods
Will my young person need a pelvic exam to investigate their heavy periods?
A genital or pelvic exam is rarely necessary to investigate a young person’s heavy periods. If your young person’s doctor suggests one, it is a good idea to ask why. They may recommend an exam in rare cases if other treatments do not work or your
young person has other symptoms that an underlying medical problem could be causing.
My young person is worried they lose a lot of blood during their period. What should I do?
No two periods are the same. If you get periods, your young person may lose more blood than you do. However, your young person can always see a doctor to make sure their iron levels are in the healthy range and rule out medical causes for their
heavy periods.
Is my young person iron deficient?
Iron deficiency is when the body does not have enough iron. It can lead to a condition called iron deficiency anaemia, where the body cannot make enough red blood cells due to low iron levels.
The most common signs and symptoms of iron deficiency are tiredness, dizziness, low energy, and looking pale. If your young person has these symptoms and gets heavy periods, they should see a doctor. They will likely need a blood test to check
their iron levels.
For more information
Developed by The Royal Children’s Hospital (RCH) Gynaecology department, with input from the Kids and Teens Pelvic Pain Clinical Network. We acknowledge the input of RCH consumers and carers.
Reviewed August 2026
Please always seek the most recent advice from a registered and practising clinician.