Iron deficiency anaemia
Table of Contents
Key takeaways
- Iron deficiency anaemia happens when the body does not have enough iron to make healthy haemoglobin, the oxygen-carrying protein in red blood cells. It is common in people who menstruate, during pregnancy, after blood loss, and when diet or absorption does not meet the body’s needs. The key clinical point is not only replacing iron, but also finding and addressing the reason iron became low.
- Iron is needed inside bone marrow to build haemoglobin. When iron stores fall, new red blood cells tend to become smaller and carry less oxygen. This can cause tiredness, breathlessness and palpitations because tissues receive less oxygen and the heart may have to work harder. In women and people who have periods, heavy menstrual bleeding is a common contributor, but gastrointestinal blood loss, pregnancy, restricted diets and absorption problems also matter.
- Assessment matters because similar symptoms can have different causes, and treatment should be matched to the confirmed diagnosis and personal risk factors.
- Seek medical advice promptly for black or bloody stools, chest pain, fainting, breathlessness at rest, very heavy bleeding, pregnancy with significant symptoms, or unexplained weight loss. Use NHS 111 for urgent advice when symptoms feel severe or rapidly worsening, and call 999 for chest pain, collapse or a life-threatening emergency.
Article type
medical_condition
Overview
Iron deficiency anaemia happens when the body does not have enough iron to make healthy haemoglobin, the oxygen-carrying protein in red blood cells. It is common in people who menstruate, during pregnancy, after blood loss, and when diet or absorption does not meet the body’s needs. The key clinical point is not only replacing iron, but also finding and addressing the reason iron became low.
Iron is needed inside bone marrow to build haemoglobin. When iron stores fall, new red blood cells tend to become smaller and carry less oxygen. This can cause tiredness, breathlessness and palpitations because tissues receive less oxygen and the heart may have to work harder. In women and people who have periods, heavy menstrual bleeding is a common contributor, but gastrointestinal blood loss, pregnancy, restricted diets and absorption problems also matter.
This article is written as a practical medical guide rather than a short definition. It covers what the condition may feel like, why it happens, which risk factors are relevant for women and families, how clinicians assess it, what treatment may involve, and when symptoms should be escalated. The aim is to support informed conversations with a GP, pharmacist, specialist clinician or emergency service, not to replace individual assessment.
Symptoms and reader concerns
Symptoms can vary in intensity, duration and impact. Some people have a clear textbook pattern, while others have subtle, overlapping or intermittent symptoms. Keep track of timing, triggers, severity, medicines, pregnancy or menopause context where relevant, and how symptoms affect sleep, work, sex, caring responsibilities or exercise.
- unusual tiredness, weakness, reduced exercise tolerance or breathlessness.
- palpitations, dizziness, headaches or feeling faint.
- pale skin, brittle nails, hair shedding, sore tongue or cracks at the corners of the mouth.
- restless legs or craving unusual substances such as ice, clay or paper.
- symptoms of an underlying cause, such as heavy periods, black stools, abdominal pain or unintended weight loss.
Symptoms that are new, persistent, one-sided, severe, linked with bleeding, breathing difficulty, fainting, pregnancy, neurological changes or rapid deterioration should be assessed promptly. It is also worth seeking help when symptoms keep returning despite reasonable self-care, because repeated episodes may indicate an underlying cause that needs targeted treatment.
Causes and risk factors
The underlying mechanism is important because it guides safe treatment. Iron is needed inside bone marrow to build haemoglobin. When iron stores fall, new red blood cells tend to become smaller and carry less oxygen. This can cause tiredness, breathlessness and palpitations because tissues receive less oxygen and the heart may have to work harder. In women and people who have periods, heavy menstrual bleeding is a common contributor, but gastrointestinal blood loss, pregnancy, restricted diets and absorption problems also matter.
Risk factors do not mean someone has caused the condition. They simply help clinicians decide what to ask about, what to test, what complications to consider and which prevention steps are realistic.
- heavy, frequent or prolonged periods, especially with clots or flooding.
- pregnancy, recent birth, breastfeeding or short gaps between pregnancies.
- low-iron dietary intake, vegan or vegetarian diets without planned iron sources, or eating disorders.
- coeliac disease, inflammatory bowel disease, bariatric surgery or medicines that irritate the stomach.
- blood loss from the bowel, which needs careful assessment, particularly after menopause or in men.
Women may also need context-specific review around heavy periods, pregnancy and birth, contraception, hormone therapy, menopause timing, pelvic symptoms, autoimmune disease or previous cancer treatment. Those details can change both the likely cause and the safest management options.
Diagnosis and assessment
Assessment usually includes a full blood count and ferritin or iron studies. Results need interpretation alongside inflammation, pregnancy, kidney disease and symptoms, because ferritin can rise during inflammation. Clinicians may also check for heavy menstrual bleeding, pregnancy, coeliac disease, bowel symptoms or medicine-related bleeding. Further investigation is important when iron deficiency is unexplained, recurrent, severe, or occurs after menopause.
A useful appointment history includes when symptoms started, whether they are improving or worsening, what has already been tried, current medicines and supplements, allergies, relevant family history and any red flags. If symptoms affect intimate health, bowel habits, periods, fertility, pregnancy or mental wellbeing, it is appropriate to say so clearly; these details are clinical information, not personal failings.
Testing should be proportionate. Some conditions are diagnosed mainly from symptoms and examination, while others need blood tests, imaging, swabs, endoscopy, ultrasound or specialist referral. If a test result is normal but symptoms continue, follow-up can still be appropriate because a single test rarely answers every clinical question.
Treatment and management
Treatment may include oral iron, dietary support and management of the cause. Oral iron is often taken for several months, but dose, timing and formulation should be individualised because nausea, constipation or dark stools can occur. Some people need intravenous iron or specialist care when tablets are not tolerated, absorption is poor, anaemia is severe, or rapid replenishment is clinically needed. Heavy periods, bowel disease or pregnancy-related needs should be treated as part of the same plan.
Good management balances symptom relief with safety. Medicines, procedures and monitoring can be helpful, but they should be chosen with the confirmed diagnosis, medical history, pregnancy or breastfeeding status, other medicines and personal preferences in mind. Ask what benefit is expected, how quickly improvement should be noticed, what side effects to watch for, and what to do if symptoms do not improve.
For longer-term conditions, follow-up is part of care rather than a sign that treatment has failed. Reviews can check whether the diagnosis still fits, whether complications are developing, whether medicines remain suitable, and whether additional support such as physiotherapy, dietetic input, psychological support, specialist nursing or consultant review is needed.
Self-care and prevention
Food can support iron stores, but diet alone may not correct significant anaemia. Useful sources include red meat, fish, poultry, beans, lentils, tofu, fortified cereals, nuts, seeds and dark green vegetables. Vitamin C-rich foods can support absorption from plant sources, while tea and coffee taken with meals may reduce iron absorption. Do not start high-dose iron long term without advice, because the correct dose and the reason for deficiency should be confirmed.
Prevention advice should be realistic and evidence-informed. It may reduce risk or symptom burden, but it should not be framed as a personal responsibility to prevent every flare, complication or recurrence. If recommended self-care is unaffordable, impractical or clashes with work, disability, caring responsibilities or cultural needs, discuss alternatives with a clinician or pharmacist.
Avoid relying on unverified home remedies for persistent or severe symptoms. Some products can irritate skin, interact with medicines, delay diagnosis or be unsuitable in pregnancy, breastfeeding, kidney disease, liver disease, diabetes or when taking anticoagulants. Pharmacy advice can be a useful first step for mild symptoms, but it has limits when red flags are present.
When to seek medical advice
Seek medical advice promptly for black or bloody stools, chest pain, fainting, breathlessness at rest, very heavy bleeding, pregnancy with significant symptoms, or unexplained weight loss. Use NHS 111 for urgent advice when symptoms feel severe or rapidly worsening, and call 999 for chest pain, collapse or a life-threatening emergency.
Bring a list of medicines, supplements, allergies and relevant diagnoses to appointments. If symptoms are intermittent, photographs, home readings, a diary or a written timeline can help, provided this is safe and does not delay urgent care. If you feel dismissed and symptoms are worsening or affecting daily life, asking for review or a second opinion is reasonable.
Sources
- NHS, Iron deficiency anaemia: https://www.nhs.uk/conditions/iron-deficiency-anaemia/
Relevance: Supports symptoms, diagnosis, treatment and dietary considerations for iron deficiency anaemia. - NICE CKS, Anaemia – iron deficiency: cks.nice.org.uk guidance page link unavailable during validation (cks.nice.org.uk guidance page, link unavailable during validation)
Relevance: Supports primary-care investigation, causes and management decisions. - NICE, Heavy menstrual bleeding NG88: https://www.nice.org.uk/guidance/ng88
Relevance: Supports the link between heavy periods, assessment and treatment planning in women. - Mayo Clinic, Iron deficiency anaemia: mayoclinic.org guidance page link unavailable during validation (mayoclinic.org guidance page, link unavailable during validation)
Relevance: Used as a benchmark for symptoms, causes, complications and treatment completeness.
Disclaimer
Educational only. Results vary. Not a cure.