Increased high molecular weight fibrinogen in pre-eclampsia

The major coagulation protein fibrinogen (Fg) is a heterogeneous protein with three main fractions: high molecular weight fibrinogen (HMW-Fg), low molecular weight fibrinogen (LMW-Fg) and low molecular weight' fibrinogen. The clottability of high molecular weight fibrinogen is highest as compared to the other fractions. Pre-eclampsia is associated with a state of hypercoagulability, and with an increase of fibrinogen concentration. The aim of the present study was to examine if the increased total fibrinogen plasma concentration in patients with pre-eclampsia is associated with a change in distribution of the main fibrinogen fractions.

Plasma was collected from 14 patients with pre-eclampsia and from 14 healthy pregnant matched controls. Total fibrinogen concentrations were determined according to Clauss. The percentage high molecular weight fibrinogen was assessed by SDS-electrophoresis and densitometry after isolation of fibrinogen by precipitation. The study groups were compared by the Mann-Whitney U-test.

The median (range) total fibrinogen concentration in the pre-eclampsia group was 5.04 (3.25-6.51) g/l and in the control group 4.19 (3.61-5.38) g/l (p<0.05). The median (range) percentage high molecular weight fibrinogen was 76.5 (69.6-84.0)% and 73.0 (69.0-78.9)% in the pre-eclampsia and control group, respectively (p<0.05).

In pre-eclampsia, the concentration of total fibrinogen is increased and the percentage high molecular weight fibrinogen is also slightly higher than in normal pregnancy. These results may be a reflection of the exaggerated inflammatory response, and subsequent endothelial activation, which are currently believed to be the key pathophysiological mechanisms in pre-eclampsia.