Why Your Periods Might Be Heavier Than Normal

Q: How do I know if my period is clinically heavy?

The clinical definition is based on whether bleeding is affecting your quality of life, not on a specific volume. Practical signs include soaking through a pad or tampon every one to two hours for several hours, passing clots larger than a 50p coin, bleeding for more than seven days, or needing to use two forms of protection at once. If any of these apply and your periods are disrupting your daily life, it is worth speaking to a GP.

Q: Can heavy periods cause tiredness?

Yes. Heavy menstrual bleeding is one of the most common causes of iron-deficiency anaemia in women of reproductive age in the UK. When your iron levels drop, you may notice persistent fatigue that does not ease with rest, weakness, shortness of breath, heart palpitations, or difficulty concentrating. A GP can check for anaemia with a blood test as part of a standard assessment for heavy periods.

Q: What conditions can cause heavy periods?

Several conditions are linked to heavy menstrual bleeding, including endometriosis, adenomyosis, uterine fibroids, endometrial polyps, thyroid disorders, and coagulation disorders such as von Willebrand disease. In many cases, no structural cause is found. A GP assessment can help identify whether something underlying is contributing. This may include an examination, blood tests and an ultrasound.

Q: What treatment options are available for heavy periods?

Treatment depends on whether an underlying cause is found and on your individual circumstances. Where no structural cause is identified and you are not trying to conceive, your GP may discuss options including the levonorgestrel-releasing intrauterine system (LNG-IUS), tranexamic acid, NSAIDs, or combined hormonal contraception. The LNG-IUS is recommended as a first-line treatment for heavy menstrual bleeding where no structural cause has been identified and contraception is acceptable to the woman.Your GP can advise on what fits your situation.

Q: When should I see a GP about my periods?

See a GP if heavy bleeding is getting in the way of your daily life, if your period lasts longer than seven days, or if you have symptoms such as pelvic pain, bleeding between periods, or signs of anaemia such as persistent tiredness or breathlessness. You do not need to wait until things become severe. If you feel unwell or bleeding is very heavy and not slowing, contact NHS 111 for prompt advice.

Pregnant woman sitting on toilet in bathroom.

The information in this article is for general informational purposes only and does not substitute for professional medical or dietary advice, particularly during pregnancy. If you are outside the UK, please consult your local doctor, midwife, or healthcare provider for guidance that reflects your country's recommendations.

Changing your pad or tampon every hour, planning your day around access to a bathroom, waking in the night because bleeding has soaked through everything: if any of this is familiar, you are likely dealing with heavy periods. That kind of bleeding takes real practical effort to manage. It is worth understanding what is actually happening in your body, what might be causing it, and what support is available on the heavy periods and menstrual cycle end of the spectrum.

What counts as heavy bleeding?

If you are soaking through a pad or tampon every one to two hours for several consecutive hours, passing clots larger than a 50p coin, bleeding for more than seven days, or needing to use a pad and tampon together, these are indicators that your menstrual bleed is heavier, and it may be worth speaking to a GP to discuss why.⁶

Heavy periods are very common. Around 1 in 3 women experience them, and they are one of the most common reasons for gynaecology referrals in the UK.⁷

Pregnant woman holding a stack of sanitary products, with a red manicure.

How does Iron loss effect your energy levels?

One of the most significant effects of heavy periods is the iron your body loses with the blood. Heavy menstrual bleeding is one of the most common causes of iron-deficiency anaemia in women of reproductive age in the UK. Over time, ongoing blood loss can deplete your iron stores to a point where your body cannot produce enough healthy red blood cells.⁸

The tiredness that comes with low iron feels different from ordinary fatigue. It can feel like persistent exhaustion that does not lift after rest, physical weakness, shortness of breath during everyday activity, heart palpitations, or difficulty concentrating. These symptoms tend to build gradually, which makes them easy to put down to other causes or simply absorb into daily life without linking them to your heavy periods.⁹

What are the possible causes of heavy periods?

Heavy periods can have a number of causes, and for some people more than one thing is contributing at the same time. A GP assessment can help work out what might be going on for you specifically.

Fibroids

Uterine fibroids are non-cancerous growths that develop in or around the womb. They are among the most common causes of heavy menstrual bleeding and are particularly common in women in their 30s and 40s. Fibroids vary considerably in size and location, and not all of them cause symptoms, but when they do, heavy bleeding is one of the most frequently reported.¹²

Polyps

Uterine polyps are small growths on the lining of the womb. Like fibroids they are usually non-cancerous, but they can cause heavier periods than usual as well as bleeding between periods. They do not always cause symptoms and many people have them without knowing. A GP can arrange an ultrasound or further tests if polyps are suspected.³

Endometriosis and adenomyosis

Endometriosis is a condition where tissue similar to the womb lining grows outside the uterus and most commonly causes pain in the second half of the cycle and lead up to periods, and is often relieved when your period arrives and needs clinical investigation to diagnose. Adenomyosis is a related but distinct condition where womb lining tissue grows into the muscular wall of the uterus itself. It is a recognised cause of heavy and prolonged bleeding, often with pelvic pain alongside it. Neither condition can be identified from symptoms alone.¹¹

Other causes worth knowing about

Alongside the more common causes, things like endometrial polyps, thyroid disorders or a condition called von Willebrand disease, which affects how blood clots, can sometimes play a part. If heavy periods have been part of your life for a while it can feel like something you just have to manage. Understanding what might be behind them can make a real difference. If your bleeding has changed or you have other symptoms alongside it, a GP can help work out what is going on for you.¹³

Supporting yourself day to day

Supporting your body through heavy periods is worth thinking about alongside anything else you are doing. Iron is one of the most important things to pay attention to, since heavy bleeding means your body is losing more of it each month than most people realise. Red meat, lentils, leafy greens and fortified cereals all contribute, and eating them alongside something rich in vitamin C helps your body make the most of what it is getting. Tea and coffee close to a meal can reduce how much iron you absorb, so spacing them out where you can is worth knowing. Some research also points to omega-3 rich foods like oily fish, walnuts and flaxseed as potentially helpful for reducing the kind of cramping and heavier flow that prostaglandins can drive. Magnesium is another nutrient that has shown up in research around both bleeding volume and cramping. On harder days, heat and gentle movement can make a difference to how you feel, and keeping track of your flow across cycles gives you a much clearer picture to bring to a GP appointment. This can include tracking abnormal bleeding such as bleeding in between periods or bleeding after sex.¹²

Things your GP might suggest

If nothing comes up in your GP assessment and you are not trying to conceive, there are options worth exploring without needing a specialist referral. These include, tranexamic acid, anti-inflammatory medicines, and hormonal contraception. Which one makes sense depends on your individual situation, whether a cause has been identified, and what feels right for you. A GP will talk through the options with you so you can make a decision together.¹⁴

When it's worth getting checked

It is worth seeing a GP if heavy periods are getting in the way of your daily life, if bleeding lasts longer than seven days, or if you have other symptoms such as pelvic pain, bleeding between periods, or signs of anaemia including persistent tiredness or breathlessness. You do not need to reach a point of crisis before seeking an assessment. Heavy menstrual bleeding is a well-recognised concern, and there are clear routes to support.¹⁵

Frequently Asked Questions

How do I know if my period is clinically heavy?

Can heavy periods cause tiredness?

What conditions can cause heavy periods?

What treatment options are available for heavy periods?

When should I see a GP about my periods?

Sources

[1] Iron deficiency anaemia - NHS

Iron is one of the most important things to pay attention to, since heavy bleeding means your body is losing more of it each month than most people realise.
[2] Iron and menstruation – British Dietetic Association

Red meat, lentils, leafy greens and fortified cereals all contribute, and eating them alongside something rich in vitamin C helps your body make the most of what it is getting. Tea and coffee close to a meal can reduce how much iron you absorb
[3] Making a decision about: managing heavy periods

Uterine polyps are small growths on the lining of the womb.
[4] Heavy menstrual bleeding in perimenopause — NICE guideline NG88

The LNG-IUS is recommended as a first-line treatment for heavy menstrual bleeding where no structural cause has been identified and contraception is acceptable to the woman.
[5] Heavy menstrual bleeding in perimenopause — NICE guideline NG88

UK clinical guidance moved away from the older threshold of 80 ml per cycle as the definition of HMB.
[6] NHS: Heavy Periods

Practical signs of heavy bleeding include soaking through a pad or tampon every one to two hours for several consecutive hours, passing clots larger than a 50p coin, bleeding for more than seven days, or needing to use a pad and tampon together.
[7] NHS: Heavy Periods

Around 1 in 3 women experience heavy periods, and they are one of the most common reasons for gynaecology referrals in the UK.
[8] NHS: Heavy Periods

Heavy menstrual bleeding is one of the most common causes of iron-deficiency anaemia in women of reproductive age in the UK.
[9] Iron deficiency anaemia - NHS

Symptoms of iron-deficiency anaemia can include persistent exhaustion, physical weakness, shortness of breath, heart palpitations, and difficulty concentrating.
[10] Heavy menstrual bleeding in perimenopause — NICE guideline NG88

A blood test to check for iron-deficiency anaemia is part of the standard GP assessment for heavy menstrual bleeding.
[11] NHS: Adenomyosis

Adenomyosis is a condition where womb lining tissue grows into the muscular wall of the uterus and is a recognised cause of heavy and prolonged menstrual bleeding, often accompanied by pelvic pain.
[12] Fibroids – NHS

Uterine fibroids are non-cancerous growths that develop in or around the womb and are among the most common causes of heavy menstrual bleeding, particularly prevalent in women in their 30s and 40s.
[13] Heavy menstrual bleeding in perimenopause — NICE guideline NG88

Other conditions associated with HMB include endometrial polyps, thyroid disorders, and coagulation disorders such as von Willebrand disease. In rare cases, endometrial cancer can present with heavy or irregular bleeding.
[14] Heavy menstrual bleeding in perimenopause — NICE guideline NG88

Treatment options discussed in primary care for HMB include the LNG-IUS (Mirena), tranexamic acid, NSAIDs, and combined hormonal contraception. The LNG-IUS is recommended as a first-line option where contraception is also acceptable.
[15] NHS: Heavy Periods

You should see a GP if heavy periods are affecting your daily life, if bleeding lasts longer than seven days, or if you have additional symptoms such as pelvic pain, bleeding between periods, or signs of anaemia.