Introduction: Pregnancy has recently been described as a generalized intravascular inflammatory response to the conceptus. Total fibrinogen concentrations increase during pregnancy. The percentage high molecular weight fibrinogen (HMW-Fg) of the concentration total fibrinogen is known to increase during acute-phase conditions like inflammation. Therefore, we investigated whether the percentage high molecular weight fibrinogen increases during normal pregnancy.
Materials and methods: Eighteen healthy nulliparous women with uncomplicated pregnancies with normal course and outcome participated in this study. Five blood samples were drawn from every woman in the gestational age periods 9 to 16, 17 to 24, 25 to 33 and 34 to 42 weeks and at 12 to 20 weeks after delivery. Total fibrinogen concentrations were determined according to Clauss and the percentage high molecular weight fibrinogen was assessed by SDS-electrophoresis and densitometry after isolation of fibrinogen by precipitation. One-way analysis of variance (ANOVA) was used to evaluate differences between gestational age periods and correlation coefficients were calculated by Pearson's method.
Results: Total fibrinogen concentrations increased with advancing gestational age and decreased after delivery. The percentage high molecular weight fibrinogen of the total fibrinogen remained unaltered during and after pregnancy.
Conclusions: During normal pregnancy, there is an increase of total fibrinogen concentrations with advancing gestational age, without a rise in percentage high molecular weight fibrinogen. After delivery, the total fibrinogen returns to baseline concentrations.