Studies on the pathophysiology and treatment of von Willebrand's disease. VI. Variant von Willebrand's disease complicating placenta previa.

The clinical course of a pregnant patient with a variant form of von Willebrand's disease (type IIA) who was complicated with placenta previa totalis, breech presentation and premature delivery is described. Following whole blood transfusion, she underwent a cesarean section without postoperative hemorrhagic complications. Factor VIII/von Willebrand factor (FVIII/vWF)-related activities (factor VIII procoagulant activity [VIII:C], factor VIII-related antigen [VIIIR:Ag] and ristocetin cofactor [VIIIR:RCo]), Duke bleeding time and platelet retention to glass beads were monitored during pregnancy, labor and puerperium. Gradual increase in FVIII/vWF-related activities and shortening of bleeding time were found during her gestation. Platelet retention, however, remained low. Qualitative analysis of plasma FVIII/vWF with crossed immunoelectrophoresis and gel filtration on Sepharose 2B demonstrated that the large forms of FVIII/vWF, which is important for primary hemostasis, did not appear in the blood during gestation. Therefore, patients with type IIA von Willebrand's disease seem to be more susceptible to bleeding complications at delivery.