Maternal thrombophilias increases the risk of an adverse pregnancy outcome. An extensive literature review highlights the role of inherited and acquired thrombophilic disorders in spontaneous abortion, both early and late, recurrent or isolate, in intrauterine growth retardation, in placenta abruption, in pre-eclampsia and in venous thromboembolism. We have particularly focused attention on the following factors: antithrombin III (ATIII), proteins C (PC) and S (PS) deficiencies, genetic mutations particularly factor V Leiden (FVL), prothrombin gene G20210A (PTM) and the thermolabile variant of the methylene tetrahydrofolate reductase C677T (MTHFR) gene, lupus anticoagulant (LAC) and anticardiolipin antibodies, VIIIc factor, hyperhomocysteinemia and acquired activated protein C resistance. Appropriate treatment can improve pregnancy outcome without teratogenic effects.