[Pregnancy and the mechanical prosthetic valve: dilemmas about the choice of antithrombotic prophylaxis]

Two pregnant women aged 32 and 34, both of whom had mechanical prosthetic mitral valves, for which they were using low molecular weight heparin. One developed orthopnoea and dyspnoea at 36 weeks amenorrhoea, and the other suffered an acute myocardial infarction at 18 weeks. Both had valvular thrombosis. Following effective treatment, both women delivered at term and one week later after an uncomplicated course, were discharged home from hospital. Clinicians caring for pregnantwomen with mechanical prosthetic valves are faced with a dilemma when trying to provide optimal treatment. Inadequate anticoagulant therapy can result in thrombosis of the mechanical prosthetic valve while, on the other hand, anticoagulant therapy is associated with foetal and maternal bleeding and teratogenic effects. Pregnant women with mechanical prosthetic valves should be thoroughly counselled before or shortly after the confirmation of pregnancy regarding the risks associated with available anticoagulant options, allowing them to make an informed decision concerning the best management plan. This is an algorithm for optimal care of these patients.