Red blood cells contain hemoglobin, which carries oxygen from your lungs through your body. Chemotherapy (chemo) can affect your red blood cells. If you have fewer red blood cells, a reduced amount of oxygen circulates through your body and you can become anemic. Anemia can make you feel very tired. It may also cause problems with your heart, brain, and nerves.

Chemo is not the only possible cause. Anemia can also be caused by:

  • Blood loss
  • Kidney disease
  • Medications
  • Vitamin or iron deficiencies
  • The cancer itself

Diagnosing Anemia

Anemia (low red blood cells) can easily be confused with other, more general problems. Watch for the following symptoms; they may suggest to your doctor that you are anemic:

  • Fatigue
  • Shortness of breath
  • Dizziness
  • Pale skin
  • Rapid heartbeat

You may not realize that you're anemic because the symptoms can be mild or even go unnoticed. But the symptoms could get worse as you become more anemic. Left untreated, anemia can cause many problems, including:

  • Fatigue
  • Heart problems
  • Nerve damage
  • Impaired mental function

Your doctor will keep close track of your blood cell counts throughout your treatment. Be sure to keep your care team aware of any symptoms of anemia you have while on chemo.


If you do become anemic, your doctor may prescribe iron or other supplements. Your doctor may talk with you about medicines to prevent anemia. If your anemia symptoms become severe, you may need a blood transfusion. There is a small risk of infection or allergic-type reactions with transfusions. As with all treatments, speak with your doctor and healthcare team about the risks and benefits of each of these treatments.

Speaking With Your Doctor

It's important to talk to your doctor and care team about your risk of developing anemia. The following questions are a great way to start a dialogue with your doctor.

Ask Your Doctor:

 Print this worksheet 
 and bring it to your next doctor's visit.

A Closer Look: Virginia*
Virginia is a 52-year-old bank executive diagnosed with stage II breast cancer. Her doctor has placed her on an aggressive chemo treatment plan.
She responds well to chemo that is known to be myelosuppressive, which means it decreases the bone marrow activity that creates new blood cells.
During her course of chemo, Virginia tells her doctor she has been feeling short of breath and fatigued. Her doctor tells her these are common side effects of chemo.
Virginia's fatigue persists. Tests show that her red blood cell counts are low. She is diagnosed with mild anemia.
Her doctor orders supplemental iron to increase her levels of red blood cells.

*This is a fictional case study based on chemo patient experiences. Your experience is unique. Your doctor and care team will create a plan that will best treat your type of cancer and manage your chemo side effects.

  • How to talk to your doctor about low red blood cell count

    If you are taking chemo it's important to talk to your doctor about your risk of developing anemia. The following questions are a great way to start a conversation with your doctor

  • The Chemotherapy and Infection Discussion Guide can help you understand your
    risk of infection

    Infection can be a serious side effect of strong chemo. Find out the factors that affect your risk of infection. Simply answer a few questions, and then print your results to share with your doctor.

    Use the Chemotherapy and Infection Discussion Guide to find out more.