Causes

By Mayo Clinic Staff

Normally low hemoglobin counts

A slightly low hemoglobin count isn't always a sign of illness — it can be normal for some people. Women with menstrual periods and pregnant women commonly have low hemoglobin counts.

Low hemoglobin counts associated with diseases and conditions

A low hemoglobin count can be associated with a disease or condition that causes your body to have too few red blood cells. This can occur if:

  1. Your body produces fewer red blood cells than usual
  2. Your body destroys red blood cells faster than they can be produced
  3. You have blood loss

Diseases and conditions that cause your body to produce fewer red blood cells than normal include:

  1. Aplastic anemia
  2. Cancer
  3. Certain medications, such as antiretroviral drugs for HIV infection and chemotherapy drugs for cancer and other conditions
  4. Chronic kidney disease
  5. Cirrhosis
  6. Hodgkin lymphoma (Hodgkin disease)
  7. Hypothyroidism (underactive thyroid)
  8. Inflammatory bowel disease (IBD)
  9. Iron deficiency anemia
  10. Lead poisoning
  11. Leukemia
  12. Multiple myeloma
  13. Myelodysplastic syndromes
  14. Non-Hodgkin lymphoma
  15. Rheumatoid arthritis
  16. Vitamin deficiency anemia

Diseases and conditions that cause your body to destroy red blood cells faster than they can be made include:

  1. Enlarged spleen (splenomegaly)
  2. Hemolysis
  3. Porphyria
  4. Sickle cell anemia
  5. Thalassemia

A low hemoglobin count can also be due to blood loss, which can occur because of:

  1. Bleeding in your digestive tract, such as from ulcers, cancers or hemorrhoids
  2. Frequent blood donation
  3. Heavy menstrual bleeding (heavy menstrual bleeding-although even normal menstrual bleeding may cause a slightly low hemoglobin count)

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

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May 13, 2025