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Factor V deficiency
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Factor V deficiency

Factor V deficiency is a rare inherited bleeding disorder that prevents blood from clotting normally, leading to prolonged or excessive bleeding.

Overview

Factor V deficiency is a rare condition where the blood does not clot properly. While symptoms can appear at any age, the most severe cases are typically identified in childhood. The condition is also known as parahemophilia or Owren disease.

Symptoms

Common signs of Factor V deficiency include:

  • Frequent nosebleeds
  • Easy bruising and bleeding under the skin
  • Bleeding of the gums
  • Prolonged or excessive bleeding following surgery, trauma, or childbirth
  • Heavy or prolonged menstrual bleeding (menorrhagia)
  • Rarely, bleeding into joint spaces (hemarthrosis)

Severely affected individuals are at risk for life-threatening internal bleeding, such as intracranial or pulmonary hemorrhage.

Causes

The condition is usually caused by mutations in the F5 gene, which provides instructions for making the coagulation factor V protein. These mutations prevent the production of functional protein or significantly reduce its levels in the bloodstream. Individuals with this condition typically have less than 10 percent of normal factor V levels; those with less than 1 percent are considered most severely affected.

In very rare cases, acquired factor V deficiency can occur when the body produces antibodies that attack and inactivate normal factor V protein. This is not a genetic condition and is often associated with exposure to substances like bovine thrombin during surgery.

Inheritance

Congenital Factor V deficiency is inherited in an autosomal recessive pattern, meaning both copies of the F5 gene in each cell must have mutations. Individuals with a mutation in only one copy of the gene may have reduced levels of the protein but typically experience only mild or no health effects.

Frequently Asked Questions

Yes, many women with Factor V deficiency have successful pregnancies, but the risk depends on the severity of the deficiency. Women with mild to moderate levels of factor V (typically above 10-20 percent) often have normal pregnancies without intervention. However, those with severe deficiency (less than 10 percent) are at higher risk for postpartum hemorrhage and may require close monitoring and prophylactic factor V replacement before delivery. A multidisciplinary team including a hematologist and obstetrician is essential to create a safe birth plan.
Early signs often appear in childhood and include easy bruising, frequent or prolonged nosebleeds, and bleeding from the gums. In girls, heavy or prolonged menstrual periods (menorrhagia) are a common indicator. If you experience bleeding that does not stop after 10-15 minutes of direct pressure, or if you notice unusual swelling or pain in a joint after minor trauma, you should consult a healthcare provider. These symptoms, especially if they are persistent or severe, warrant blood tests to check clotting factors.
Treatment depends on the severity of the bleeding and the patient's specific factor V levels. For mild bleeding, such as nosebleeds or minor cuts, local measures like pressure, ice, or topical hemostatic agents may be sufficient. For more significant bleeding or before surgery, replacement therapy is required. This involves infusing fresh frozen plasma (FFP) or specific factor V concentrates. In cases of acquired deficiency where antibodies are present, treatment may also include immunosuppressive medications to stop the body from attacking the factor V protein.
Congenital Factor V deficiency is a rare genetic disorder inherited in an autosomal recessive pattern, meaning a person must inherit two mutated copies of the F5 gene to have the condition. It is present from birth and results in low levels of functional factor V protein. Acquired Factor V deficiency is not genetic; it occurs when the body produces antibodies that attack and neutralize normal factor V protein. This acquired form is often triggered by exposure to bovine thrombin, a substance sometimes used in surgical procedures to control bleeding, and it can develop in adulthood without any family history of bleeding disorders.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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