Righini M, Jobic C, Boehlen F, Broussaud J, Becker F, Jaffrelot M, Blondon M, Guias B, Le Gal G, the EDVIGE study group. Predicting deep venous thrombosis in pregnancy: external validation of the LEFT clinical prediction rule. Haematologica 2013; 98(4):545-548; https://doi.org/10.3324/haematol.2012.072009.