Fibrinogen fractions in the third trimester of pregnancy and in puerperium

The concentration of fibrinogen, its fractions, and the concentration of C-reactive protein were determined in 45 healthy pregnant women before and after vaginal (27) or caesarean section (18) delivery. The control group consisted of 33 blood donors. In pregnancy, increased concentration of total fibrinogen and its fractions and a normal concentration of C-reactive protein were noted. Three days after vaginal delivery the concentration of total and high molecular weight fibrinogen fraction decreased slightly and the ratio of high to low molecular weight fibrinogen increased. After caesarean section both total and high molecular weight fibrinogen and the ratio of high to low molecular weight fibrinogen increased. The C-reactive protein concentration increased after either type of delivery. The degree of augmentation, however, was ten times as strong after caesarean section. In all women at the end of puerperium the concentrations of the compounds studied returned to normal values, The results suggest that the mechanisms leading to the increase of fibrinogen during pregnancy and after delivery are different. The increase of all fibrinogen fractions in pregnancy may depend first of all on hormones, whereas the increased proportion of high molecular weight to low molecular weight fibrinogen after delivery depends on the acute phase reaction. The degree of this reaction depends on the type of delivery. (C) 2000 Elsevier Science Ltd. All rights reserved.