Hemophilia is a rare bleeding disorder in which the blood doesn't clot normally.

Hemophilia usually is inherited. "Inherited” means that the disorder is passed from parents to children through genes.

People born with hemophilia have little or no clotting factor. Clotting factor is a protein needed for normal blood clotting. There are several types of clotting factors. These proteins work with platelets (PLATE-lets) to help the blood clot.

The two main types of hemophilia are A and B. If you have hemophilia A, you're missing or have low levels of clotting factor VIII (8). About 8 out of 10 people who have hemophilia have type A. If you have hemophilia B, you're missing or have low levels of clotting factor IX (9).

Rarely, hemophilia can be acquired. This can happen if your body forms antibodies (proteins) that attack the clotting factors in your bloodstream. 

A defect in one of the genes that determines how the body makes blood clotting factor VIII or IX causes hemophilia. These genes are located on the X chromosomes.

A male who has a hemophilia gene on his X chromosome will have hemophilia. When a female has a hemophilia gene on only one of her X chromosomes, she is a "hemophilia carrier” and can pass the gene to her children. Very rarely, a girl may be born with hemophilia.

Some males who have the disorder are born to mothers who aren't carriers. In these cases, a random genetic change occurs in the gene as it is passed to the child.

The major signs and symptoms of hemophilia are excessive bleeding and easy bruising.

The extent of bleeding depends on how severe the hemophilia is. Bleeding can occur externally or internally.

Signs of external bleeding may include:

  • Bleeding in the mouth from a cut or bite or from cutting or losing a tooth
  • Nosebleeds for no obvious reason
  • Heavy bleeding from a minor cut
  • Bleeding from a cut that resumes after stopping for a short time

Signs of internal bleeding may include:

  • Blood in the urine (from bleeding in the kidneys or bladder)
  • Blood in the stool (from bleeding in the intestines or stomach)
  • Large bruises (from bleeding into the large muscles of the body)

If you or your child appears to have a bleeding problem, your doctor will ask about your personal and family medical histories. This will reveal whether you or your family members, including women and girls, have bleeding problems. However, some people who have hemophilia have no recent family history of the disease.

You or your child 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 clotting factors

  • Whether any clotting factors are completely missing from your blood

The test results will show whether you have hemophilia, what type of hemophilia you have, and how severe it is.

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 or injected into a vein. These infusions help replace the clotting factor that's missing or low.

Other Types of Treatment


Desmopressin (DDAVP) is a man-made hormone used to treat people who have mild hemophilia A. DDAVP isn't used to treat hemophilia B or severe hemophilia A.

DDAVP stimulates the release of stored factor VIII and von Willebrand factor; it also increases the level of these proteins in your blood. 

Antifibrinolytic Medicines

Antifibrinolytic medicines (including tranexamic acid and epsilon aminocaproic acid) may be used with replacement therapy. They're usually given as a pill, and they help keep blood clots from breaking down.