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Diseases reference index «Factor II deficiency»

Factor II deficiency is a blood clotting (coagulation) problem that occurs when there is a lack of a substance (prothrombin) that is needed for blood to clot.


When you bleed, the body launches a series of reactions that help the blood clot. The process involves special proteins called coagulation factors. Factor II is one of many coagulation factors. The final product of these chain reactions is the blood clot.

When certain coagulation factors are too low or missing, your blood may not clot normally. Bleeding may range from mild to severe.

Factor II deficiency that runs in families (inherited) is very rare. It results in poor blood clotting. Both parents must be carriers to pass it to their children. A family history of a bleeding disorder is a potential risk factor.

Most commonly, factor II deficiency is caused by:

  • Lack of vitamin K (or deficiency) from long-term use of antibiotics, bile duct obstruction, or poor absorption of nutrients from the intestines (intestinal malabsorption)
  • Severe liver disease
  • Use of drugs that prevent clotting (anticoagulants)

Some babies are born with vitamin K deficiency.


  • Abnormal bleeding after delivery
  • Abnormal menstrual bleeding
  • Bleeding after surgery
  • Bleeding after trauma
  • Bruising
  • Nosebleeds (epistaxis)
  • Umbilical cord bleeding at birth

Exams and Tests

  • Factor II assay
  • Partial thromboplastin time
  • Prothrombin time (PT)


You can control blood loss by getting infusions of fresh or frozen plasma or concentrates of clotting factors into the blood. If the disorder is caused by a lack of vitamin K, you can take vitamin K by mouth (orally), through injections under the skin, or through a vein (intravenously).

Diagnosing a bleeding disorder is important so that the doctor can take extra care if you need surgery, and can test or warn other family members who might be affected.

Support Groups

You can ease the stress of illness by joining a support group where members share common experiences and problems. See hemophilia - resources.

Outlook (Prognosis)

The outcome can be good with proper treatment.

This is a life-long bleeding disorder if you get it from your parents.

If it is caused by liver disease, the outcome depends on how well you control the liver problem. Taking vitamin K will treat vitamin K deficiency.

Possible Complications

Severe bleeding, even into the brain can occur.

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if you have unexplained or long-term blood loss or if you can't control the bleeding.


Genetic counseling may be helpful for disorders that start at birth (congenital). When a lack of vitamin K is the cause, using vitamin K can help.

Alternative Names

Hypoprothrombinemia; Prothrombin deficiency

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