First trimester recurrent fetal loss and severe second or third trimester placental vascular disorders are still frequently unexplained. Acquired biological thrombophilia (antiphospholipid syndrome, essential thrombocythemia) are known risk factors. Genetic thrombophilia may represent a new risk factor for placental vascular diseases, but reported data are conflicting. Combined hereditary thrombophilias are indeed a moderate risk factor, but even in these cases most pregnancies are normal giving healthy live birth children. Whether hereditary thrombophilia is associated with recurrent severe placental vascular disorders is unknown.