What is the main cause of anaemia?

Written By Lotte May
Founder of Comfort Crate & Cancer Advocate

What is Anaemia?

Anaemia is a common blood disorder that occurs when the body doesn't produce enough red blood cells or haemoglobin—the protein that carries oxygen to your tissues. One of the leading causes is iron deficiency, though it can also be triggered by medications or chronic illness. When oxygen delivery is reduced, it leads to a wide range of complications.

Navigate Your Side Effects: Understanding why you feel fatigued is the first step to recovery. Our Conquer Cancer Guidebook provides a deep dive into blood health. It includes symptom trackers to help you monitor lightheadedness and poor concentration, plus nutritional advice to support your bone marrow during chemotherapy.

What Causes Anaemia in Cancer Treatment?

Anaemia is a common side effect of cancer treatment. Some cancers cause inflammation that decreases red blood cell production, while many chemotherapies are myelosuppressive—meaning they slow down the production of blood cells within your bone marrow.

The Role of Bone Marrow and Kidneys

Bone marrow is the spongy tissue inside your bones that produces billions of red blood cells every day. Additionally, your kidneys produce a hormone called erythropoietin (EPO), which signals the bone marrow to make these cells. Chemotherapy can affect both the bone marrow and the kidneys because it targets fast-dividing cells. Damage to either can lead to a drop in red blood cell production.

Fortunately, this effect is usually temporary. One study found that while 89.5% of people receiving chemotherapy for solid tumours experienced some level of anaemia, most saw improvement within a few months of ending treatment.

Symptoms and Effects

When you have anaemia, your heart has to work harder to pump oxygen-rich blood throughout your body. Symptoms include:

• Extreme fatigue and drowsiness.
• Shortness of breath and rapid heartbeat.
• Lightheadedness, dizziness, or fainting.
• Pale skin and poor concentration.
• Headaches and loss of appetite.

How to Manage Anaemia

Most forms of anaemia are treatable. Treatment usually involves addressing the underlying cause—such as replenishing iron levels through supplements or dietary changes. In some cases, medical procedures like blood transfusions or bone marrow transplants may be required.

Read more: Blog: Detailed Treatments for Anaemia

Further Reading and Support (Unique UK Resources)

• Cancer Centre: Anaemia Care
  A UK-based hub providing peer support and detailed explanations on the various types of anaemia, including vitamin-deficiency and aplastic anaemia.
• NHS: Iron Deficiency Anaemia Overview
  The official UK clinical guide on symptoms, diagnostic blood tests, and what to expect from iron supplement prescriptions.
• Blood Cancer UK: Understanding Your Blood Counts
  A vital resource helping UK patients decode their blood test results (Full Blood Count) and understand what the "normal" range looks like during chemo.

About the Author: Lotte May is a stage 4B Hodgkin Lymphoma survivor and founder of Comfort Crate. She uses her research background to provide patients with evidence-based tools for side effect management. Read more about her mission here.

Medical Disclaimer: This information is for support and guidance only. It does not replace the advice of your medical team.