APC Resistance and other Haemostatic Variables during Pregnancy and Puerperium

TLDR

Forty‑eight healthy pregnant women were followed prospectively, with blood samples taken at 10‑15, 23‑25, 32‑34, 38‑40 weeks and at 1 week and 8 weeks postpartum. Classic and modified activated protein C ratios fell throughout pregnancy, with 92 % of classic ratios above the lower reference in the third trimester and all modified ratios normal, while markers of coagulation activation (prothrombin fragment 1+2, soluble fibrin, D‑dimer) and levels of fibrinogen, factor VIII, PAI‑1/2 rose, protein S and tPA activity fell, protein C stayed unchanged, and no correlations were found between APC ratio changes and the other haemostatic variables.

Abstract

Summary Forty-eight healthy pregnant women were studied prospectively and longitudinally. Blood sampling was performed at 10-15, 23-25, 32-34 and 38-40 weeks of gestation, within one week and at eight weeks postpartum. Classic and modified activated protein C ratio decreased as pregnancy progressed. In the third trimester 92% of the ratios measured with the classic test were above the lower reference level whereas all modified test ratios were normal. Slight activation of blood coagulation was shown with increased levels of prothrombin fragment 1+2, soluble fibrin and D-dimer. Fibrinogen, factor VIII and plasminogen activator inhibitor type 1 and type 2 increased. Protein S and tissue plasminogen activator activity decreased. Protein C remained unchanged. No correlation was found between the decrease in classic APC ratio and changes in factor VIII, fibrinogen, protein S, prothrombin fragment 1+2 or soluble fibrin, nor between the increase in soluble fibrin and changes in prothrombin fragment 1+2, fibrinogen and D-dimer.