抄録
It is well known that fibrinolytic activity is much reduced during pregnancy but rapidly returns to non-pregnant levels after delivery. However the cause of this pronounced reduction in fibrinolytic activity in pregnancy has not yet been established. We were interested to investigate the mechanism of reduction in fibrinolytic activity during pregnancy. In order to determine whether tissue plasminogen activator (tPA) antigen in plasma decreases during pregnancy or not, we have measured tPA antigen by an enzyme immunoassay in 43 healthy non-pregnant women (control), 73 apparently healthy pregnant women and 54 women in puerperium. Simultaneously several factors (plasminogen, protein C, FXII, FXI, α2PI, α2M, α1AT, C1INA, AT-III), which may interfer with fibrinolytic activity have been measured.
The levels of tPA antigen in the plasma from pregnant women at the both first and second trimeters are similar to that of control plasma (6.0±3.1ng/ml). However, the level of tPA antigen in plasma rises progressively after the second trimester and is maximum (17.7±6.4ng/ml) 3 hrs after delivery. Then it decreases rapidly and by the first day after delivery, it returns to the control level.
We studied change of several other fibrinolytic factors during pregnancy, but we could not explain the fact that fibrinolysis is reduced in pregnancy in spite of an increase of tPA antigen.
