Risk factors for deep venous thrombosis and pulmonary embolism (see table Risk Factors for Deep Venous Thrombosis and Pulmonary Embolism) are similar in children and adults and include Conditions that impair venous return, including bed rest and confinement without walking Conditions that cause endothelial injury or dysfunction Underlying hypercoagulable (thrombophilic) disorders such as cancer or primary clotting disorders COVID-19 appears to be a risk factor for deep venous thrombosis and pulmonary embolism.