We report two cases of von Willebrand (type I) disease with vWF antigen levels of 21 and 25%, vWF ristocetin cofactor concentrations of 32 and 30%, and coagulation FVIII levels of 10 and 50% respectively. Template bleeding times were 20 and 11 minutes respectively. Both of these women exhibited a progressive and marked improvement of the vWF/FVIII complex during pregnancy. In the first, all parameters had completely normalized in the 37th week when a cesarean section was performed without hemorrhagic complications. The second case had borderline normal levels of the vWF/FVIII complex in the 37th week and underwent normal delivery in the 39th week. The improvement persisted for at least one week post-partum and in the first case values were still higher 10th weeks after delivery than they had been prior to the pregnancy. These observations and similar cases in the recent literature suggest that obstetrical operations and normal delivery are not associated with major blood losses in cases of moderately severe vWD of type I. These patients probably will not need vWF/FVIII concentrates for adequate hemostasis.