What is hemophilia?

In hemophilia, blood does not clot properly. This usually happens because your body does not have enough of a certain kind of clotting factor. This makes it harder for bleeding to stop. People with hemophilia may bleed a lot after cuts, during surgery, or even after a fall. Some people have abnormal bleeding inside their bodies for no clear reason.

There are two main types of hemophilia:

• Hemophilia A is caused by a lack of active clotting factor VIII (8). About 1 out of every 5,000 male babies is born with hemophilia A.¹
• Hemophilia B (Christmas disease) is caused by a lack of active clotting factor IX (9). It is less common and affects 1 out of 30,000 male babies.¹

Hemophilia usually runs in families and almost always affects males. In rare cases, a person may get a type that does not run in the family. This is called acquired hemophilia, and it affects both males and females.

What causes hemophilia?

Hemophilia A and B are caused by a flaw in a pair of chromosomes. This flaw affects how much clotting factor a person has and how well it works.

With acquired hemophilia, clotting factors don't work right because the body makes antibodies that attack them.

What are the symptoms?

Symptoms of hemophilia include:

• Bleeding into a joint or muscle, which causes pain and swelling.
• Bleeding that is not normal after an injury or surgery.
• Easy bruising.
• Frequent nosebleeds.
• Blood in the urine.
• Bleeding after dental work.

Some people with milder types of the disease may not have symptoms until later in life. But most of the time, hemophilia symptoms are noticed during infancy or childhood. Symptoms noticed in infants include:

• Bleeding into the muscle, which causes a deep bruise after the baby gets a routine vitamin K shot.
• Bleeding that goes on for a long time after a baby is circumcised.
• Bleeding that goes on for a long time after the umbilical cord is cut. This is rare.

How is hemophilia diagnosed?

If your doctor thinks that you or your child may have a problem with blood clotting, he or she will take a blood sample. The sample will be used in tests that check for the amount clotting factor, the type of hemophilia, and how severe the disease is.

How severe the disease is depends on how much clotting factor is produced and when bleeding most often occurs.

• Mild hemophilia: Clotting factor level is at least 5% of normal. This type might not be noticed unless there is a lot of bleeding after a major injury or surgery.
• Moderate hemophilia: Clotting factor level is 1% to 5% of normal. Bleeding normally follows a fall, sprain, or strain.
• Severe hemophilia: Clotting factor level is less than 1% of normal. Bleeding often happens one or more times a week for no reason.