When you bleed, a series of reactions take place in the body that helps blood clots form. This process is called the coagulation cascade. It involves as many as 20 different special proteins called coagulation, or clotting, factors. You may have a higher chance of excess bleeding if one or more of these factors are missing or are not functioning like they should.

Factor V deficiency is caused by a lack of factor V. When certain blood clotting factors are low or missing, your blood does not clot properly.

Factor V deficiency is rare. It may be caused by:

• A variant factor V gene passed down through families (inherited)
• An antibody that interferes with normal factor V function

You can develop an antibody that interferes with 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 childbirth often occurs. Other symptoms can include:

• Bleeding into the skin
• Bleeding of the gums
• Excessive bruising
• Nosebleeds
• Prolonged or excessive loss of blood with surgery or trauma
• Umbilical stump bleeding

Tests to detect factor V deficiency include:

• Factor V assay
• Blood clotting tests, including partial thromboplastin time (PTT) and prothrombin time (PT)
• Bleeding time

You will be given fresh blood plasma or fresh frozen plasma infusions during a bleeding episode or after surgery. These treatments will correct the deficiency temporarily.

The outlook is good with diagnosis and proper treatment.

Severe bleeding (hemorrhage) could occur.

Go to the emergency room or call 911 or the local emergency number if you have an unexplained or prolonged loss of blood.

Parahemophilia; Owren disease; Bleeding disorder - factor V deficiency

Gailani D, Benjamin FT, Wheeler AP. Rare coagulation factor deficiencies. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 135.

Ragni MV. Coagulation factor deficiencies. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 160.

Samelson-Jones BJ, Branchford BR, Flood VH. Hereditary clotting factor deficiencies (bleeding disorders). In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 525.

Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.