Symptom guide
Heavy periods: causes, red flags and when to get it checked
Periods are considered heavy when they interfere with daily life, involve flooding, clots, or needing to change protection very often or overnight. Fibroids, polyps, adenomyosis, hormonal imbalance and bleeding disorders are among the causes. It can cause iron deficiency anaemia, so a blood test is part of the assessment.
Last checked: 2026-10-03
Key facts
At a glance.
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What counts
Bleeding that disrupts your life, needs frequent changes, passes large clots or causes tiredness is heavy, whatever the measured amount.
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Iron
Heavy periods are a leading cause of iron deficiency, so tiredness and breathlessness matter.
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Common causes
Hormonal changes, fibroids, polyps, adenomyosis, coil and bleeding disorders.
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Treatable
Medicines, a hormonal coil, and procedures like ablation or surgery can reduce bleeding.
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Who to see
GP; gynaecology for ultrasound or hysteroscopy if persistent or no response.
What this symptom usually means
The womb lining builds each month under the influence of oestrogen and progesterone, and sheds in a period. Anything that thickens the lining, interferes with the womb muscle contracting, or impairs clotting can make bleeding heavier. A pattern that starts suddenly or becomes heavier is worth checking.
Possible causes, from most to least common
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No cause found (dysfunctional uterine bleeding), often linked to ovulation changes, especially in teens and in perimenopause.
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Fibroids: benign muscle growths in the womb, with heavy, prolonged periods, pressure and sometimes pain.
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Adenomyosis and endometriosis: heavy, painful periods and a tender, enlarged womb.
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Endometrial or cervical polyps, causing heavy or irregular bleeding.
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Polycystic ovary syndrome, thyroid disease and other hormonal imbalances.
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Copper coil, and medicines such as anticoagulants.
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Bleeding disorders such as von Willebrand disease, particularly if heavy periods began at the first period.
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Endometrial hyperplasia or cancer, particularly with irregular bleeding, obesity or over 45.
Features that point to something more serious
Bleeding between periods or after sex, a new change in pattern after 45, heavy bleeding with pelvic pain or a mass, extreme tiredness and breathlessness suggesting anaemia, bleeding after menopause, and a family history of womb or bowel cancer deserve prompt assessment.
Red flags: when to seek help
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Call 999 or go to A&E: soaking through a pad every hour for several hours with dizziness or fainting, or heavy bleeding with a positive pregnancy test.
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Same-day GP: heavy bleeding with severe pain, fever or breathlessness.
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GP within weeks: heavy periods affecting daily life, tiredness or pallor; bleeding between periods; or bleeding after sex.
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Routine: a one-off heavier period after stress or illness.
What a doctor will ask and examine
The doctor asks about cycle length, duration, clots, flooding, protection use, pain, tiredness, family history of bleeding, contraception, fertility plans, smear history and medicines. They check pulse and blood pressure, examine the abdomen and may perform a pelvic examination.
Tests that are commonly used and why
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Full blood count and ferritin: for anaemia and low iron.
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Thyroid function and, if indicated, clotting studies or a bleeding disorder screen.
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Pelvic ultrasound (often transvaginal): for fibroids, polyps and thickened lining.
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Hysteroscopy and endometrial biopsy: for persistent bleeding, over 45 or when treatment fails.
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Pregnancy test where relevant.
Self-care and the usual route
Track your periods with a diary or app. Iron-rich foods help, but tablets are only needed if tests show deficiency. Tranexamic acid and anti-inflammatory medicines taken during periods can reduce bleeding, a hormonal coil is a very effective option, and hormonal tablets can also help; these are prescribed after assessment. Procedures include endometrial ablation, fibroid treatments and hysterectomy.
The NHS route is a GP, then gynaecology if needed. Private gynaecology offers direct access to ultrasound, hysteroscopy and procedures.
Frequently asked
Questions people ask.
Quick, plain-English answers to the questions we hear most.
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How heavy is too heavy?
If bleeding disrupts normal life, needs very frequent changes, causes flooding or clots, or leads to tiredness, it is heavy enough to seek help.
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Can heavy periods cause anaemia?
Yes. Blood loss depletes iron, causing tiredness, breathlessness and pallor. A blood test checks it.
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What are fibroids?
Non-cancerous growths in the muscle of the womb. They are common and can cause heavy periods and pressure symptoms.
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What helps heavy bleeding?
Tranexamic acid, anti-inflammatories, a hormonal coil or contraceptive pill, and procedures if needed.
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Do I need an ultrasound?
If bleeding is persistent, treatment fails, or an examination suggests fibroids or polyps, a pelvic ultrasound is usually arranged.
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Is it perimenopause?
In the forties, heavy and irregular periods are common as ovulation becomes erratic, but bleeding changes should still be reviewed.
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Could it be a bleeding disorder?
It is possible if heavy bleeding began at your first period, with easy bruising, nosebleeds or bleeding after dental work.
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What is endometrial ablation?
A procedure to destroy the womb lining to reduce or stop periods, for women who have completed their families.
Where this comes from
Sources and checking.
This guide is for information, not medical advice.
Your GP or consultant knows your history and can tell you which parts apply to you. If your symptoms are severe, rapidly worsening, or come with red-flag features, seek urgent medical care. Figures and availability change, so treat them as a guide and confirm with the provider.
Published 2026-10-03, next review 2027-10-03.
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NHS: Heavy periods (nhs.uk/conditions/heavy-periods/)
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NICE guideline NG88: Heavy menstrual bleeding - assessment and management
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NHS: Fibroids (nhs.uk/conditions/fibroids/)