Summary
Pregnancy is associated with increased risk of venous thromboembolism, especially
in the presence of thrombophilia. However, there is no consensus on the optimal approach
for thromboprophylaxis in this population. Recent evidence suggests that thrombin
generation correlates with the overall procoagulant state of the plasma. Our aim was
to evaluate thrombin generation in a prospective cohort of thrombophilic pregnant
women, and investigate the effectiveness of low-molecular- weight heparin (LMWH) prophylaxis
in pregnancy. Women with severe (n=8), mild (n=47) and no (n=15) thrombophilia were
followed throughout their pregnancies. Thrombin generation was evaluated in each trimester
as well as five days and eight weeks postpartum (as a reference category). In women
undergoing LMWH prophylaxis, thrombin generation and anti-Factor-Xa activity were
measured just before and 4 hours after administration (peak effect). Thrombin generation
was determined using Technothrombin TGA assay system. For the analysis, median peak
thrombin and endogenous thrombin potential were used. Peak thrombin and endogenous
thrombin potential were increased during pregnancy compared to the non-pregnant state
with the highest results in the severe thrombophilia group. In women receiving LMWH
prophylaxis a decrease was observed in thrombin generation at peak effect but over
the progression of pregnancy the extent of this decrease reduced in a stepwise fashion.
Our results show that thrombin generation demonstrates the hypercoagulable state in
thrombophilic pregnancies. In addition, we found the effect of LMWH prophylaxis to
progressively decrease with advancing stages of pregnancy.
Keywords
Thrombophilia - pregnancy - LMWH prophylaxis - thrombin generation