[Prosthetic mechanic valve thrombosis in pregnant women: a report of two cases].

Patients with prosthetic mechanical heart valves should always be on prophylactic anticoagulation therapy for thromboembolic events. As pregnancy represents a high-risk period for thrombosis, those with mechanical heart valves should be accorded greater importance. We presented two pregnant patients with prosthetic mechanical mitral valves, who developed mechanical valve thrombosis while on fractionated and unfractionated heparin treatment, respectively. One patient received intensive anticoagulation treatment, and the other underwent redo valve replacement. Both patients were free of symptoms.