Heritable Thrombophilia and Pregnancy Associated Thrombosis.

Venous thromboembolism VTE is the major cause of morbidity and mortality in pregnant woman in industrialized countries. VTE is said to occur at the rate of about 1 per 1000 pregnancies[1,2]. It is important to note that the frequency of asymptomatic DVT is probably not negligible specially in multiparity women as shown by the results of the Sirius Study in which multiparity was found to be a risk factor for VTE[3]. A small number of studies have clearly shown that in women with heritable thrombophilia (antithrombin, protein C deficiency), the risk of VTE during pregnancy is significantly increased but these thrombophilias are rare[4-6]. The more recently discovered thrombophilias in particular the Factor V Leiden and the F II 20210A gene mutation are much more frequent. Their discovery has stimulated clinical investigation on this subject[7-10]. The most common inherited thrombophilia is heterozygosity for the F V Leiden since in control caucasian populations, its incidence is about 6%.