What causes anaemia?

Red blood cells carry oxygen around the body. When they cannot do this effectively, tiredness, shortness of breath, dizziness, headaches, paleness, or a racing heartbeat can develop. Symptoms vary with the cause and how quickly the anaemia develops.

Iron deficiency anaemia is a frequent cause. It can follow low iron intake, reduced iron absorption, or blood loss, including heavy periods or bleeding from the digestive tract. Vitamin B12 deficiency and folate deficiency can also interfere with normal red blood cell production.

Some long-term conditions affect how the body makes red blood cells. Chronic kidney disease can reduce a signal involved in red blood cell production. Inherited conditions such as thalassaemia affect haemoglobin itself and need a different assessment from nutritional deficiency.

Arrange a medical appointment if you have persistent symptoms or have been told that your haemoglobin is low. A clinician may ask about diet, menstrual bleeding, medicines, digestive symptoms, family history, and other health conditions, then arrange blood tests to identify the pattern of anaemia.

Treatment should match the cause. Iron, vitamin B12, or folate supplements may help when a deficiency is confirmed, while blood loss, kidney problems, and inherited conditions need their own management. Avoid starting high-dose supplements solely to treat unexplained symptoms, because they can obscure the cause or be unsuitable for you.

Seek urgent medical help for chest pain, severe shortness of breath, fainting, confusion, or a fast heartbeat that does not settle. Also seek prompt assessment for black or bloody stools, vomiting blood, or unusually heavy bleeding, as these can point to significant blood loss.

Pregnancy, known kidney disease, and a family history of an inherited blood disorder are useful details to mention when arranging care. They help the clinician choose appropriate tests and treatment.

Ask what type of anaemia the blood results suggest, whether there are signs of iron or vitamin deficiency, and whether bleeding or another condition needs investigation. If treatment is advised, ask how it will be monitored and which symptoms should prompt earlier review.