[Low molecular heparin in a pregnant women with heart valve prosthesis]

Women with a prosthetic heart valve who wish to bear a child face a difficult choice. Continued medication with warfarin during pregnancy will offer her a reasonable good protection against thrombosis, but carries a considerable risk of teratogenic effects. Subcutaneously administered heparin is an alternative to warfarin. Standard (unfractionated) heparin has not offered sufficient protection against valve thrombosis, which may be a life-threatening complication. We were contacted by a woman who wished to become pregnant and who did not want to use warfarin if this implied a risk for the foetus. We followed a protocol using low molecular weight heparin in rather high doses. The dose was adjusted according to the results of blood test controls, which confirmed increased need for anticoagulation as the pregnancy evolved. Serial eccocardiography excluded valve thrombosis. The woman needed psychological support from her general practitioner. No complications occurred, and she gave birth to a normal child. We describe the various alternatives for anticoagulant treatment in pregnant women with mechanical heart valves. The choice of anticoagulant regimen and their consequences must be thoroughly discussed with the woman.