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. Factor V deficiency is caused by inheriting a defective Factor V gene. In this disorder, bleeding ranges from mild to severe.

The disease is similar to hemophilia, except bleeding into joints is less common. Bleeding can occur almost anywhere in the body, and death from hemorrhage has occurred with this disorder.

Excessive bleeding with menstrual periods and after delivery occurs frequently. A family history of a bleeding disorder is a risk factor. Men and women are affected equally, and the incidence is about 1 in 1 million.