AbstractObjective: To evaluate the role of plasminogen activators (tPA uPA) and inhibitor (PAI‐1) in the pathogenesis of preeclampsia.Study Design: tPA uPA and PAI‐1 antigens were measured in amniotic fluid, maternal plasma, and placental homogenates in normal pregnancy by ELISA method and compared with that of preeclampsia.Results: In normal pregnancy, tPA, uPA and PAI‐1 levels increase as the gestation advance, but the increment of PAI‐1 in amniotic fluid (28.3‐fold) is larger than that of tPA and uPA (1.8‐fold, 8.5‐fold) (p<0.001). Decidua homogenates contained larger amount of PAI‐1 than villi. Whereas, villi had higher levels of tPA uPA than decidua (p<0.01). In preeclampsia, the significantly higher levels of PAI‐1 were observed in AF and decidua tissue as compared to the normals (p<0.01), and the increment of PAI‐1 in preeclampsia is larger than that of tPA, uPA.Conclusions: The elevated PAI‐1 level is associated with the preeclampsia and the imbalance between the plasminogen activators (tPA, uPA) and the inhibitor (PAI‐1) might be involved in the patho