Bleeding disorders affect a person’s ability to effectively form a blood clot (or thrombus) when an injury occurs. If you have a bleeding disorder, you may have defective or decreased platelet and/or coagulation factors which make it hard for your body to form effective blood clots normally, and you may experience bleeding complications which can range from mild to severe.

If you have been diagnosed with a clotting disorder, it means unexpected clotting or thrombosis has occurred in your veins or arteries. This often happens in the legs, which is referred to as deep vein thrombosis (DVT). Sometimes a clot can travel to the lung, which is referred to as pulmonary embolism (PE). You may experience pain or swelling in your legs, shortness of breath, or chest pain.

Bleeding disorders often develop when the blood can’t clot properly. For blood to clot, your body needs blood proteins called clotting factors and blood cells called platelets. Normally, platelets clump together to form a plug at the site of a damaged or injured blood vessel. The clotting factors then come together to form a fibrin clot. This keeps the platelets in place and prevents blood from flowing out of the blood vessel.

In people with bleeding disorders, however, the clotting factors or platelets don’t work the way they should or are in short supply. When the blood doesn’t clot, excessive or prolonged bleeding can occur. It can also lead to spontaneous or sudden bleeding in the muscles, joints, or other parts of the body.

The majority of bleeding disorders are inherited, which means they’re passed from a parent to their child. However, some disorders may develop as a result of other medical conditions, such as liver disease.

Bleeding disorders may also be caused by:
a low red blood cell count
a vitamin K deficiency
side effects from certain medications