Hemophilia is the term for a group of blood clotting disorders, characterized by frequent and heavy bleeding. An estimated 20,000 people in the United States have some form of hemophilia, according to figures from the Centers for Disease Control and Prevention (CDC). 

There are different forms of hemophilia: hemophilia A occurs when there is an insufficient quantity of the blood clotting factor VIII; hemophilia B is a hereditary condition caused by a lack of blood clotting factor IX; hemophilia C is also caused by a lack of clotting factor IX, and it usually has mild symptoms. 

Common signs and symptoms of hemophilia include unexplained or excessive bleeding after surgery or injury, numerous large bruises, blood in the urine or stool, frequent nosebleeds, fatigue, and pain or swelling in the joints. Hemophilia can result in a number of other complications, such as deep internal bleeding, damage to the joints, a higher risk of infection, and adverse reactions to clotting factor treatment. 

There is no cure for hemophilia, but treatment may alleviate the symptoms and prevent bleeding episodes. Ongoing treatment often includes infusions with a clotting factor, medication to preserve clots, physical therapy, and vaccinations to prevent against infection. Drug classes commonly used to treat hemophilia include vasopressin (ADH) and analogs,  synthetic antifibrinolytics, and blood coagulation factors.