FIBRINOLYTIC COMPONENTS IN INDIVIDUAL CONSECUTIVE PLASMA SAMPLES DURING NORMAL-PREGNANCY

Background and Methods. Variation in fibrinolytic capacity during normal pregnancy is still the subject of debate. In recent studies of newer fibrinolytic components, values have been obtained at different gestational ages, but not followed in individual cases throughout pregnancy. We therefore carried out a longitudinal study where fibrinolytic components were followed throughout normal pregnancy in 48 women sampled at 10, 20, 25, 28, 32, 36 and 38 weeks of gestation, and in the first stage of labour. Results. The plasma concentrations of t-PA antigen, u-PA antigen, PAI-1 antigen, PAI-1 activity, PAI-2 antigen, and D-dimer were measured. All these variables manifested marked increases to the end of the 38th week, after which they all began to decrease except t-PA antigen and D-dimer which continued to increase. Conclusions. The results obtained from individual samples yield the actual pattern of development during pregnancy for each component, a requirement for further research of fibrinolytic components under pathological conditions. The change from increase to decrease after the 38th week for u-PA and PAI-2, components chiefly involved in growth regulation, probably mirrors the end of the placenta remodelling process. The increase of t-PA antigen and the decrease of PAI-1 antigen and activity after the 38th week contributes to a remaining fibrinolytic potential capable of degrading fibrin deposits, as reflected in a further increase in the plasma D-dimer concentration.