Factor XI Deficiency

Factor XI deficiency is an inherited bleeding disorder that is caused by a problem with factor XI. Because the body produces less factor XI than it should, or because the factor XI is not working properly, the clotting reaction is blocked prematurely and the blood clot does not form.

Factor XI deficiency is also called haemophilia C. It differs from haemophilia A and B in that there is no bleeding into joints and muscles. Factor XI deficiency is the most common of the rare bleeding disorders and the second most common bleeding disorder affecting women (after von Willebrand\’s disease).

Some people have inherited factor XI deficiency when only one parent carries the gene. The disorder is most common in Ashkenazi Jews, that is, Jews of Eastern European ancestry.

Common symptoms

  • Nosebleeds (epistaxis)
  • Easy bruising
  • Heavy or prolonged menstrual bleeding (menorrhagia)
  • Abnormal bleeding during or after injury, surgery, or childbirth


Other reported symptoms

  • Bleeding in the gut (gastrointestinal haemorrhage)
  • Bleeding in the mouth, particularly after dental surgery or tooth extraction
  • Blood in the urine (hematuria)



Factor XI deficiency is diagnosed by a variety of blood tests that should be performed by a specialist at your Comprehensive Care Centre.


There are several treatments available to help control bleeding in people with factor XI deficiency.

  • Factor XI concentrate
  • Antifibrinolytic drugs
  • Fibrin glue
  • Fresh Frozen Plasma (FFP)


Excessive menstrual bleeding in women with factor XI deficiency may be controlled with hormonal contraceptives (birth control pills) or antifibrinolytic drugs.

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