Alternative names
Factor II deficiency; Prothrombin deficiency

Factor II deficiency is a disorder of blood clotting (coagulation) resulting from a deficiency of prothrombin.

Causes, incidence, and risk factors

Normal blood coagulation is a complex process involving as many as 20 different plasma proteins, which are known as blood coagulation factors. A series of complex chemical reactions using these factors takes place very rapidly to form an insoluble protein called fibrin that stops bleeding. When certain coagulation factors are deficient or missing, the chain reaction does not take place normally. In this disorder, bleeding ranges from mild to severe.

A congenital factor II deficiency is a very rare inherited disorder that results in deficient blood clotting. It is inherited as an autosomal recessive trait (both parents are carriers). A family history of a bleeding disorder is a risk factor.

Acquired factor II deficiency is common and results from vitamin K deficiency, severe liver disease, and therapeutic use of anticoagulant drugs. Risk factors for vitamin K deficiency are prolonged use of antibiotics, bile duct obstruction, and intestinal malabsorption (inadequate absorption of nutrients from the intestinal tract) disorders. Some newborns are born with vitamin K deficiency.


  • Umbilical cord bleeding at birth  
  • Nose bleeds  
  • Abnormal menstrual bleeding  
  • Abnormal bleeding after delivery  
  • Bleeding after trauma  
  • Bleeding after surgery  
  • Bruising

Signs and tests

  • Prolonged prothrombin time  
  • Prolonged partial thromboplastin time  
  • Factor II assay showing decreased activity

Loss of blood can be controlled by infusions of fresh or frozen plasma or concentrates of clotting factors. If the disorder is caused by vitamin K deficiency, then vitamin K is prescribed. Diagnosis of a bleeding disorder is important so that precautionary measures can be taken if surgery is needed or anticipated.

Support Groups
The stress of illness can often be helped by joining a support group where members share common experiences and problems. See hemophilia - resources.

Expectations (prognosis)
This is a life-long bleeding disorder when it is inherited. If it is caused by liver disease, the outcome depends on the control of the liver problem. Vitamin K administration will correct vitamin K deficiency.

Bleeding into the brain or skull can occur.

Calling your health care provider
Go to the emergency room, or call the local emergency number (such as 911) if you have unexplained or prolonged blood loss, or if bleeding does not respond to the usual methods of control.

Genetic counseling may be helpful in the case of congenital disorders. The use of vitamin K in malabsorption and long-term antibiotic use may be preventive.

Johns Hopkins patient information

Last revised: December 3, 2012
by Levon Ter-Markosyan, D.M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.