[Epidemiology and maternal thrombosis].

The monthly incidence of deep vein thrombosis during pregnancy varies from 0.1 to 0.8 per 1000 pregnancies, depending on the study. These figures are undoubtedly an underestimation because they were determined from clinical events with no estimation of asymptomatic forms which, in general, increase the prevalence about 3-fold. Although the absolute figures are reliable, the consequences in terms of maternal mortality and post-phlebitis sequelae warrant the careful attention paid to this condition. Moreover, it should be recalled that the prevalence of superficial venous thrombosis is similar and may be associated with a risk of pulmonary embolism.