Causes

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:

• Your body produces fewer red blood cells than usual
• Your body destroys red blood cells faster than they can be produced
• You have blood loss

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

• Aplastic anemia
• Cancer
• Certain medications, such as antiretroviral drugs for HIV infection and chemotherapy drugs for cancer and other conditions
• Chronic kidney disease
• Cirrhosis
• Hodgkin's lymphoma (Hodgkin's disease)
• Hypothyroidism (underactive thyroid)
• Inflammatory bowel disease (IBD)
• Iron deficiency anemia
• Lead poisoning
• Leukemia
• Multiple myeloma
• Myelodysplastic syndromes
• Non-Hodgkin's lymphoma
• Rheumatoid arthritis
• Vitamin deficiency anemia

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

• Enlarged spleen (splenomegaly)
• Hemolysis
• Porphyria
• Sickle cell anemia
• Thalassemia

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

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