Pregnancy is a hypercoagulable state secondary to an increase in coagulation factors, a reduction in naturally occurring anticoagulants, and impairment of fibrinolysis.
Pregnancy losses were divided into preclinical, first trimester clinical, and second trimester. A meaningfully increased rate of preclinical pregnancy failure in Leiden mutation carriers was found than in no activated protein C deficiency patients.
Another cause of miscarriages is inherited thrombophilia following damage to the maternal factor V gene G1691A (Leiden mutation) and prothrombin gene (G20210A mutation). These alterations are well studied and the test is part of the routine diagnostics of recurrent mis-carriages. In the case of factor V, both the Leiden mutation G1691A and the T1328C mutation appear to be important in the pathogenesis of RM, mainly in cases observed before the 7th week of gestation.
The most common causes of inherited thrombophilia are polymorphisms in genes encoding factor V, prothrombin (factor II), factor VII, MTHFR, and plasminogen activator inhibitor, while protein C, protein S and ant thrombin deficiency is less common.
The finding of a link between FVL carrier state and early RPL would have significant implications for clinical practice, as it would provide a scientific rationale for screening for FVL mutation and targeted thromboprophylaxisin affected women.