What Are the Causes of Decreased Platelets?

Thrombocytes, more commonly known as platelets, are fragments of cells that circulate in the blood. They aid in blood clotting. A low platelet count can lead to excessive bleeding; conversely, when too many platelets collect in the blood vessels, a blood clot can lead to a stroke or pulmonary embolism. The medical term for low platelet count is thrombocytopenia, and it can be caused by several conditions and a few medications.

Nutrient Deficiencies

• Nutrient deficits can cause a low platelet count. Vitamin B12 and folic acid are both involved in the production and maintenance of platelets. Vegans are particularly susceptible to vitamin B12 deficiency because this nutrient is only found in animal proteins. Pregnant women need additional folic acid to maintain a healthy pregnancy. A high-quality multivitamin will usually cure these deficiencies.

Infection

• Infections that affect the blood are especially likely to cause a low platelet count. Septicemia, some viruses and systemic viral or bacterial infections are all potential culprits. The bacterial infection E. coli can cause a rare condition called hemolytic uremia syndrome. This disease destroys platelets and red blood cells and interferes with kidney function.

Medications

• The Mayo Clinic reports medications that can reduce platelet count, "...include heparin, quinidine, quinine, sulfa-containing antibiotics, anticonvulsants and gold salts." These medicines reduce platelets by inducing a reaction in the immune system that destroys platelets.

Pregnancy

• Pregnancy causes a low platelet count in about 8 percent of pregnancies, according to Dr. Enrique Vazquez Vera, of Medscape Reference. This is likely due to the fact that platelets have a shorter lifespan during pregnancy. In cases of pregnancy-related thrombocytopenia, platelet counts typically return to normal a few weeks after delivery.

Autoimmune Disease

• Some autoimmune diseases contribute to a low platelet count, including lupus and rheumatoid arthritis. These conditions cause the body to attack healthy tissue, including platelets.

Idiopathic Thrombocytopenic Purpura

• Idiopathic thrombocytopenic purpura (ITP) is when a person's platelet count is low for no discernible reason. The Mayo Clinic points out that this may be an incorrect immune reaction, in which a person's body misidentifies platelets as a threat and then attacks them.