Factor V deficiency is an inherited condition that affects the ability of the blood to clot.

Normal blood coagulation is a complex process involving as many as 20 different proteins in blood plasma, which are known as blood coagulation factors. A series of complex chemical reactions using these factors takes place very rapidly to form a protein called fibrin, which stops bleeding.

Factor V deficiency is caused by a lack of the plasma protein Factor V. When certain coagulation factors are low or missing, the chain reaction does not take place normally. Factor V is rare, and can be caused by inheriting a defective Factor V gene or by acquiring an antibody that interferes with normal Factor V function.

You can acquire an inhibitor of Factor V:

• After giving birth
• After being treated with a certain type of fibrin glue
• After surgery
• With autoimmune diseases and certain cancers

Sometimes the cause is unknown.

The disease is similar to hemophilia, except bleeding into joints is less common. In the inherited form of Factor V deficiency, a family history of a bleeding disorder is a risk factor.

Excessive bleeding with menstrual periods and after delivery often occurs. Men and women are affected equally. About 1 person per 1 million has the disorder.