Concentrations of plasminogen activators and their inhibitors in blood preconceptionally, during and after pregnancy.
BACKGROUND
Haemostasis is a complex balance of activating and inhibitory pathways resulting in coagulation and lysis. Normal pregnancy is associated with hypercoagulation that is even more profound in complicated pregnancies.


OBJECTIVE
To study the role of the plasminogen-activator system in complicated pregnancy with regard to haemostasis, it is essential to have reference values of components of this system during uneventful pregnancy. In this study we investigated the concentrations of six different components of the plasminogen-activator system preconceptionally, during and after uncomplicated pregnancies.


METHODS
Tissue-type and urokinase-type plasminogen activator (tPA and uPA), plasminogen inhibitor type-1 and -2 (PAI-1 and-2), and the complexes between tPA and PAI-1, and between uPA and PAI-1 (tPA-PAI-1, uPA-PAI-1) were measured by ELISAs in blood obtained preconceptionally, at 6, 10, 20, 32 weeks of gestation, and 6 weeks after delivery in uncomplicated pregnancies (n=41; all six parameters n=22).


RESULTS
tPA and uPA concentrations decreased in the first 10 weeks of pregnancy and subsequently increased in the third trimester. PAI-1 concentrations increased in the third trimester and PAI-2 concentrations increased throughout pregnancy (preconception versus 32 weeks of gestation; 38.73 versus 102.23ng/ml, and 0.024 versus 151.06ng/ml, respectively). tPA-PAI-1 and uPA-PAI-1 complex concentrations decreased in the first trimester, followed by an increase in the third trimester. The concentrations of all components returned to the preconception values 6 weeks after delivery.


CONCLUSIONS
This study provides longitudinal data on activating and inhibitory components of the plasminogen-activator system during pregnancy. Insight in the longitudinal changes in these concentrations may be of help in the understanding of the thrombotic tendency in pregnancy complications such as preeclampsia.
Department of Obstetrics and Gynaecology, Division of Obstetrics and Prenatal Medicine, Erasmus University Medical Centre, Rotterdam, The Netherlands.
Marianne
M
Coolman
Christianne J M
CJ
de Groot
Eric A P
EA
Steegers
Anneke
A
Geurts-Moespot
Chris M G
CM
Thomas
Régine P M
RP
Steegers-Theunissen
Fred C G J
FC
Sweep
D000328:Adult; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood*; D017396:Plasminogen Activator Inhibitor 2 / Q000097:blood*; D011247:Pregnancy / Q000097:blood*; D011248:Pregnancy Complications / Q000097:blood; D011264:Pregnancy Trimesters; D010959:Tissue Plasminogen Activator / Q000097:blood*; D014568:Urokinase-Type Plasminogen Activator / Q000097:blood*
D017395:Plasminogen Activator Inhibitor 1; D017396:Plasminogen Activator Inhibitor 2; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator