Von Willebrand disease (VWD) is a common inherited condition that can sometimes cause heavy bleeding. People with VWD have a low level of a substance called von Willebrand factor in their blood, or this substance doesn't work very well.
Von Willebrand factor helps blood cells stick together (clot) when you bleed. If there isn't enough of it or it doesn't work properly, it takes longer for bleeding to stop. There is currently no cure for VWD, but it doesn't usually cause serious problems and most people with it can live normal, active lives.