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Hemophilia is a rare bleeding disorder in which your blood doesn't clot normally. If you have hemophilia, you may bleed for a longer time than others after an injury. You also may bleed internally, especially in your knees, ankles, and elbows. This bleeding can damage your organs or tissues and may be life threatening.


The major signs and symptoms of hemophilia are excessive bleeding and easy bruising. Bleeding can occur on the body's surface (external bleeding) or inside the body (internal bleeding).


If you have inherited hemophilia, you're born with the condition. It's caused by a defect in one of the genes that determine how the body makes blood clotting factor VIII or IX. These genes are located on the X chromosomes

Chromosomes come in pairs. Females have two X chromosomes, while males have one X and one Y chromosome. Only the X chromosome carries the genes related to clotting factors. A male who has the abnormal gene on his X chromosome will have hemophilia. A female must have the abnormal gene on both of her X chromosomes to have hemophilia; this is very rare.


If hemophilia is suspected, your doctor will take your personal and family medical histories. This will reveal whether you or anyone in your family has a history of frequent and/or heavy bleeding and bruising.

You also will likely have a physical exam and blood tests to diagnose hemophilia. Blood tests are used to find out:

  • How long it takes for your blood to clot
  • Whether your blood has low levels of any of the clotting factors
  • Whether one of the clotting factors is completely missing from your blood


The main treatment for hemophilia is called replacement therapy. Concentrates of clotting factor VIII (for hemophilia A) or clotting factor IX (for hemophilia B) are slowly dripped in or injected into a vein. These infusions help replace the clotting factor that's missing or low.

Clotting factor concentrates can be made from human blood that has been treated to prevent the spread of diseases, such as hepatitis. With the current methods of screening and treating donated blood, the risk of getting an infectious disease from human clotting factors is very small.

To further reduce that risk, you or your child can take clotting factor concentrates that don't use human blood. These are called recombinant clotting factors. Clotting factors are easy to store, mix, and use at homeā€”it only takes about 15 minutes to receive the factor.

You may have replacement therapy on a regular basis to prevent bleeding. This is called preventive or prophylactic therapy. Or, you may only need replacement therapy to stop bleeding when it occurs. This use of the treatment, on an as-needed basis, is called demand therapy.

Demand therapy is less intensive and less expensive than preventive therapy. However, there's a risk that bleeding will cause damage before the demand therapy is given.



National Heart, Lung, and Blood Institute, USA.