Postpartum bleeding and von Willebrand's disease.

We calculated the decreases in hemoglobin levels between the day of delivery and postpartum day 3 in all 3565 deliveries of the year 1997. Fourteen patients had a drop in hemoglobin level of more than 8% and were included in the study. Ten women without excessive bleeding served as a control group. In all women tested, plasma von willebrand factor antigen (vWF:Ag) correlated well with factor VIII:C activity, and both were within normal limits, so that we were able to exclude the presence of type I von willebrand's disease (vWD I). Two women in the excessive bleeding group were found to have an isolated decrease in coagulation factor activity. In one patient, factor XI:C and XII:C activities were reduced to 46% and 53% respectively, and APTT was prolonged to 48.5 seconds. In the other, factor VII:C activity had dropped to 69%, and Normotest results were only 62%. Ten of the 14 patients and 1 woman of the control group were diagnosed as having mild anemia. We conclude that investigations for vWD I should only be done in women with a previous history of abnormal bleeding.