title: Protein Z in normal pregnancy.
abstract: Changes in the coagulation and fibrinolytic systems during pregnancy lead to a higher risk of thromboembolism. These changes include the increase of many clotting factors, as well as a significant fall in activity of fibrinolytic proteins, such as protein C. Protein Z is a vitamin-K-dependent plasma glycoprotein and inhibits the activation of factor X by serving as a cofactor to a plasma proteinase inhibitor. Protein Z deficiency has recently been reported in women with unexplained early fetal losses, and antibodies to protein Z can contribute to adverse pregnancy outcomes. The aim of this study was to determine the range of protein Z in normal pregnancies at different gestational weeks in a cross-sectional and a longitudinal setting. In the longitudinal study we found a 20% increase (p=0.006) of protein Z from first trimester to delivery and a 30% decrease (p<0.0001) 6 to 12 weeks after delivery. In the cross-sectional study these findings were reproducible. In summary, our data show a progressive increase in protein Z levels with gestational age in normal pregnancies and a return to normal levels around 6 to 12 weeks postpartum. The normal increase of protein Z during pregnancy may balance the increase of clotting factors to protect pregnant women from thrombosis.
authors.affiliation: Clinic of Obstetrics, Zurich University Hospital, Frauenklinikstrasse 10, 8091 Zurich, Switzerland. kquack@bluewin.ch
authors.forename: Katharina C
authors.initials: KC
authors.lastname: Quack Loetscher
authors.forename: Ruth
authors.initials: R
authors.lastname: Stiller
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Roos
authors.forename: Roland
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D000328:Adult; D001798:Blood Proteins / Q000032:analysis / Q000502:physiology / Q000592:standards*; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D008137:Longitudinal Studies; D049590:Postpartum Period / Q000097:blood; D011247:Pregnancy / Q000097:blood*; D012016:Reference Values
chemical_list: D001798:Blood Proteins; C026080:plasma protein Z