Factor V Leiden

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Factor V Leiden (five LY dehn) is an inherited blood disorder. It is not contagious (it cannot be passed through person-to-person contact). It is genetic (in the genes). Genes are tiny parts of cells that tell the cells how to grow. We inherit a set of genes from each parent. Doctors can find out if your child has Factor V Leiden by genetic testing. Children who have Factor V Leiden have a slight risk for developing blood clots. This can happen after a surgery or illness, or if a person does not move around enough (immobility).

Signs and Symptoms

Call your child’s doctor right away if your child has any symptoms of a blood clot.

Early signs of blood clot are:

  • Leg or arm pain
  • Leg or arm swelling
  • Shortness of breath
  • Chest pain


Most people with Factor V Leiden do not develop blood clots and do not need treatment.

If blood clots become an issue, "blood-thinning" medicines (like Enoxaparin) can be used. This will halt growth of the clot and reduce the risk of future clots.


Since Factor V Leiden is an inherited condition, there is no way to prevent it. There are, however, lifestyle choices that reduce the risk of abnormal blood clots:

  • Get regular physical activity.
  • If on a long airplane flight, stand up and move around regularly.
  • If on a long car trip, stop about every 2 hours and walk for a few minutes.
  • Avoid estrogen-containing birth control.
  • Do not smoke cigarettes.

Factor V Leiden (PDF)

HH- I-420 5/17 Copyright 2017, Nationwide Children's Hospital