Summary
Hypercoagulability is observed in patients with inherited thrombophilia, e.g. factor
V Leiden (FVL) mutation. Pregnancy represents a hypercoagulable state as well. This
study addresses the effects of the FVL mutation on haemostatic activation during pregnancy
as indicated by prothrombin fragments (F1+2). 233 pregnant women with no history of
venous thromboembolism were studied. Additionally, two patient groups (25 pregnant
FVL carriers and 36 pregnant women without thrombophilic diathesis) in whom low molecular
weight heparin (dalteparin) was used prophylactically against rethrombosis were investigated.
None of the women developed clinical signs of venous thromboembolism during pregnancy
or after delivery. Untreated women exhibited substantial hypercoagulability. F1+2
levels were similar in FVL carriers and non-carriers (difference n. s.). After sufficient
adjustment for anti-factor Xa activity (≥0.15; ≤0.4 U/mL), heparinized women without
any thrombophilic diathesis had significantly lower levels of F1+2 than untreated
pregnant women. This was evident only in the first and second trimenon (p <0.01).
F1+2 levels in heparinized FVL carriers were quite similar to the levels observed
in untreated pregnant women, however. In conclusion, our data support the thesis that
in comparison to asymptomatic patients, thrombin generation is exaggerated in symptomatic
FVL carriers. Coagulation activation during pregnancy can be reduced by dalteparin.
Keywords
Pregnancy - thromboembolism - thrombophilia - low molecular weight heparin