Aim To determine the exact time period when clotting factor levels decrease post partum.

Background Pregnancy is a haemostatic challenge associated with elevated levels of clotting factors. However it is not known when clotting factors return to prepregnancy levels following delivery.

Method The authors assessed factor VIII (FVIII) and von Willebrand factor (VWF) activity in 95 women during labour and days 1, 2 and 3 of the puerperium.

Results There were no significant differences in FVIII, VWF:Ag and VWF:CB between baseline and days 1 and 2 of the puerperium. There was however a significant decrease between baseline and day 3 in VWF:Ag (p=0.009) and VWF:CB (p=0.04). FVIII levels while decreasing progressively from active labour to the different days post partum, showed no significant decline within any of the time points analysed. Age, ethnicity, duration of labour and mode of delivery did not have any significant effect on the changes in FVIII and VWF levels.

Conclusion Our results show that while a significant drop of VWF occurs during the period analysed, a decline did not occur to a significant degree for FVIII. The initial decline in FVIII is more gradual, therefore reducing the potential for haemorrhage. The sharper decline in VWF acts to reduce the chance of thromboembolic complications. Decreases in both factors occurring at different rates within the 72 h post partum may be beneficial in preventing both haemorrhage and thrombosis.