Test Your Knowledge of Bleeding Disorders

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What Is A Bleeding Disorder?

Bleeding disorders are conditions in which the blood does not clot normally because certain proteins in the blood are missing or do not work properly.

Von Willebrand Disease

Von Willebrand disease (VWD) is a disorder in which the blood does not clot properly. Blood contains many proteins that help the blood clot when needed. One of these proteins is called von Willebrand factor (VWF). People with VWD either have a low level of VWF in their blood or the VWF protein doesn’t work the way it should. There are three types of VWD: type 1 (the most common and mildest form of VWD), type 2, and type 3 (the most severe form of VWD).

The signs and symptoms of VWD include:


Hemophilia is an inherited bleeding disorder in which the blood does not clot properly due to a lack or decrease in a protein called clotting factor. The two most common types of hemophilia are hemophilia A, which is due to a lack of clotting factor VIII (8) and hemophilia B, which is due to a lack of clotting factor IX (9).

The signs and symptoms of hemophilia include:

  • Frequent or hard-to-stop nosebleeds.
  • Easy bruising.
  • Longer-than-normal bleeding after injury, surgery, and dental work.
  • Bleeding into the joints. This can cause swelling and pain or tightness in the joints; it often affects the knees, elbows, and ankles.
  • Bleeding into the skin (which is bruising) or muscle and soft tissue causing a build-up of blood in the area (called a hematoma).

Who Is Affected by Bleeding Disorders?

VWD is the most common bleeding disorder, found in up to 1% of the U.S. population. This means that 3.2 million (or about 1 in every 100) people in the United States have the disease. Although VWD occurs among men and women equally, women are more likely to notice the symptoms because of heavy or abnormal bleeding during their menstrual periods and after childbirth.

The exact number of people with hemophilia is unknown.

Eric standing on the street with palm trees in the background

With no family history of hemophilia, Eric's diagnosis was completely unexpected. Now, his diagnosis gives him purpose and a community.

The majority of hemophilia and VWD cases are inherited and there is a known family history of the disorder. However, about one-third of families with babies who are diagnosed with hemophilia report having no known history of the disorder. Hemophilia can also be caused by a spontaneous (random) change in a mother or child’s gene.

Read personal stories from people who have VWD and hemophilia to learn more about their experiences. Living with the complications of a bleeding disorder can be challenging; however, with treatment, people with bleeding disorders can manage their bleeding symptoms.

If you would like to share your personal story, please contact the Division of Blood Disorders through CDC-INFO

What is CDC Doing to Help People with Bleeding Disorders?

Community Counts

Community Counts is a public health monitoring program funded by CDC’s Division of Blood Disorders. The goal of Community Counts is to monitor the health of people living with hemophilia and other bleeding disorders who are receiving care at more than 145 U.S. Hemophilia Treatment Centers (HTCs).

The Community Counts program gathers and shares information from HTCs about the characteristics of people with bleeding disorders, and their treatments, bleeding symptoms, and long-term medical complications.

Data from Community Counts has informed public health and clinical guidelines and practices to prevent or reduce hemophilia-related health problems. Read a summary report on the Community Counts program, or read the full report here.

If you or someone you know has a bleeding disorder, learn more about Community Counts eligibility and participation here.

Better You Know

The Better You Know campaign, developed by the National Hemophilia Foundation in partnership with the CDC, raises awareness of bleeding disorders among women and girls who may experience symptoms but have not yet been diagnosed. As many as 1% of women in the United States may have a bleeding disorder, and many do not know it. The Better You Know campaign was created to help you find out if you might be at risk for a bleeding disorder.

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Women and girls can take a free, web-based risk assessment to learn whether they may be at risk for a bleeding disorder on the Better You Know webpage. If they are at risk, free tools and resources are available in English and Spanish to help them take steps towards seeking care. These resources will help women and girls receive testing as well as an accurate diagnosis and treatment plan, if needed, from their healthcare providers.

Better You Know also has resources for healthcare providers and educators to increase their knowledge and awareness of bleeding disorders in women.

Visit CDC’s webpage to learn more about bleeding disorders in women and girls and how you can take steps to protect your health.

Take this quiz to test your knowledge about hemophilia and VWD!