Changes in the levels of factor VIII and von Willebrand factor in the puerperium.

To determine changes in Factor VIII (FVIII) and von Willebrand Factor (VWF) in the first 3 days of the puerperium. A prospective study assessing FVIII clotting activity, VWF activity and antigen levels in 95 women (with singleton uncomplicated pregnancies) during labour and on days 1, 2 and 3 of the puerperium. There were no significant differences in FVIII, VWF:Ag and VWF:CB on days 1 and 2 of the puerperium compared with levels during labour. There was a significant decrease in VWF:Ag (P = 0.009) and VWF:CB (P = 0.04) on day 3. Age, ethnicity, duration of labour and mode of delivery did not have any significant effect on the changes in FVIII and VWF levels. The pregnancy induced increase in FVIII and VWF is maintained in the first 48 h after delivery. VWF levels start to decline on day 3 postdelivery.