Pregnancy outcomes in women with mechanical prosthetic heart valves.

Pregnancy outcomes in women with mechanical heart valves (MHV) remain poor. The thrombogenicity of MHV, the hypercoagulable state of pregnancy and limitations of current anticoagulation strategies combine to give a very high risk state. Recent additions to the literature in the form of registry data as well as meta-analyses and systematic reviews have highlighted the risks of thrombotic and haemorrhagic events in mothers and increased fetal complication rates. There remains a lack of consensus about the optimal anticoagulation approach to mitigate the risks to mother and fetus and registry data confirm poor quality of care. Current guidelines recommend the sequential use of heparin and vitamin K antagonists, but low molecular weight heparin is often used throughout the pregnancy, with inadequate monitoring in many instances. There is an urgent need to standardise the management of such women, which should be undertaken in specialist centres, supported by research on optimal anticoagulation regimens and the impact on pregnancy outcomes.