Heavy periods are common, often very treatable, and almost never something to just put up with. This guide explains what actually counts as menorrhagia (the medical term for heavy menstrual bleeding), why bleeding can change through your 30s and 40s, the link to iron-deficiency anemia, and the red flags worth getting checked.
What counts as a heavy period?
"Heavy" is partly personal, but clinicians use practical signs rather than measuring exact millilitres. You likely have heavy menstrual bleeding if one or more of these sounds familiar.
| Sign of a heavy period | What it looks like in real life |
|---|---|
| Soaking through protection fast | Soaking a pad or tampon every 1-2 hours, for several hours |
| Large clots | Passing blood clots bigger than a quarter (about 2.5 cm, or a 10p coin) |
| Flooding | A sudden gush that leaks through clothes or bedding |
| Double protection | Needing a tampon and a pad together to stay dry |
| Long periods | Bleeding that regularly lasts more than 7 days |
| It limits your life | Planning days around the bathroom, missing work, school, or events |
If your period limits what you can do, that counts — regardless of the numbers. It also matters if your bleeding suddenly becomes much heavier or longer than your own normal. A useful rule of thumb: the thresholds in this table describe a generally heavy period, while soaking through a pad or tampon every hour for several hours in a row is the more urgent end of the spectrum and warrants same-day medical advice.
Heavy periods and iron-deficiency anemia
The most common consequence of heavy periods is losing more iron than your body can replace, which can lead to iron-deficiency anemia. This builds quietly over months, so many women do not connect their symptoms to their periods. Watch for the common iron-deficiency symptoms:
- Unusual tiredness or low energy that rest does not fix
- Breathlessness on stairs or mild exertion
- Looking pale, feeling dizzy, or a racing heartbeat
- Headaches, brittle nails, or hair shedding
A simple blood test can check for anemia and your ferritin (your iron stores), which can run low even before anemia shows up on a standard count. Alongside any treatment a clinician advises, eating foods high in iron supports your levels. Do not start iron supplements long-term without a test, because too much iron is also a problem and the symptoms of low and high iron can overlap.
What causes heavy periods?
Often no single cause is found, but the usual suspects are worth knowing — especially because they shift with age.
Hormonal changes (very common in your 40s)
In perimenopause, estrogen and progesterone swing erratically. In cycles where you do not ovulate, the womb lining builds up under estrogen without the progesterone that normally balances it, then sheds heavily. Heavier, closer-together, or unpredictable periods are one of the most common — and most normal — signs of this transition, and you can read more in our guide to irregular periods in perimenopause. An underactive or overactive thyroid can also cause heavy bleeding.
Growths in or on the womb
- Fibroids — non-cancerous muscle growths in the womb wall, a leading cause of heavy bleeding.
- Polyps — small, usually non-cancerous soft growths on the womb lining.
- Adenomyosis — womb-lining tissue growing into the muscle wall, often with heavy, painful periods.
Other causes
- PCOS — irregular ovulation in polycystic ovary syndrome can lead to a thickened lining and heavy bleeds.
- Bleeding disorders — conditions like von Willebrand disease, especially if you have bled heavily since your very first periods.
- Some IUDs and medications — the copper coil can increase bleeding, and blood thinners (anticoagulants) can too.
Note that the hormonal IUD is different from the copper coil: it usually reduces bleeding and is often used as a treatment, which we cover below.
How heavy periods are investigated
You do not need to have everything figured out before you go in. A clinician will usually:
- Ask about your pattern — tracking a few cycles (length, how often you change protection, clots, pain, and any bleeding between periods) gives them a head start.
- Run blood tests — to check for anemia and low ferritin, and sometimes thyroid function or a clotting problem.
- Examine and, if needed, scan — a pelvic exam and often an ultrasound to look for fibroids, polyps, or adenomyosis. Occasionally a sample of the womb lining (a biopsy) is taken, particularly if the lining looks thickened or you are over 45.
None of these steps commit you to treatment. They simply help match any treatment to the actual cause, which is why a clear picture of your own pattern is so valuable.
How heavy periods are treated
There are good options, and the right one depends on the cause, whether you want to conceive, and your preferences. Described in general terms — not a prescription — they include:
- Non-hormonal medicines — tranexamic acid taken during your period to reduce flow, or anti-inflammatories (NSAIDs) that can reduce flow and ease cramping. These do not affect your fertility, so they suit women trying to conceive.
- Hormonal treatments — the hormonal IUD (often very effective for heavy bleeding), the combined pill, or progestogen, which thin the lining over time. See hormone therapy for related menopause-stage options.
- Treating the cause — for example, managing thyroid disease, a bleeding disorder, or PCOS.
- Procedures — removing polyps or fibroids, endometrial ablation, or, as a definitive option, hysterectomy. These are usually considered when other treatments have not worked or are not suitable.
Many women improve a lot with the simplest options, so it is worth starting the conversation early rather than waiting for things to feel unbearable.
Heavy periods, pain, and related symptoms
Heavy bleeding and pain often travel together. Some period pain is normal, but pain that is severe, getting worse, or disrupting your life is not something to simply endure — it can point to endometriosis, fibroids, or adenomyosis, which are treatable once identified. Bleeding between periods or after sex, or periods that suddenly become much heavier or longer than your normal, also deserve a check; see our guide to spotting between periods. Tracking the bleeding and the pain together gives a clinician the fullest picture.
What to track before your appointment
A short, honest record beats trying to remember everything in the room. For two or three cycles, jot down:
- The first and last day of each period, so you can see length and gaps.
- How often you change protection on your heaviest days, and whether you flood or double up.
- Any clots, and roughly how large.
- Pain and how it affects your day, plus any bleeding between periods or after sex.
- Energy levels and symptoms like breathlessness that might point to anemia.
This guide is educational, not a diagnosis. Tracking your cycle and sharing the pattern with a clinician is the fastest route to feeling better.
When to see a clinician
Heavy periods are common, but some situations need medical attention — sometimes urgently.
- Any bleeding after menopause — vaginal bleeding 12 or more months after your last period is not normal and should be checked promptly. It is usually not serious, but it can occasionally signal womb (endometrial) cancer, so never ignore it. See when periods stop if you are unsure where you are in the transition.
- Very heavy bleeding — soaking through a pad or tampon every hour for several hours, passing large clots, or "flooding" warrants care.
- Signs of anemia — extreme tiredness, breathlessness, dizziness, or looking pale.
- A sudden change — periods becoming much heavier or longer than your normal, bleeding between periods, or bleeding after sex.
- Severe or worsening period pain — pain that disrupts your life can point to endometriosis, fibroids, or adenomyosis and deserves assessment.
- Sudden severe pelvic pain, pain with a fever, or pain when pregnancy is possible — this needs urgent care, as it can rarely signal an ectopic pregnancy or another emergency.
- Feeling faint, a racing heart, or breathless at rest — seek urgent care.
You know your own body. If something feels wrong, or a symptom is new and persistent, it is always reasonable to get it checked.
