The purpose of this study was to conduct a systematic review of the literature of studies that examined the association between inherited thrombophilias and adverse pregnancy outcomes. We have evaluated developments in this area published since 1998. The published studies differ widely in design, mostly in patients and controls selection and in data analytic approach. Despite the growing evidence in the literature, there are still gaps in our knowledge of thrombophilia in pregnancy, expecially regarding less prevalent thrombophilic defects, such as deficiencies in antithrombin, protein C, and S. Several studies on the association on factor V Leiden showed that it may play a role not only in second trimester losses, but also in pre-eclampsia, intrauterine growth-retardation, and placental abruption. Studies on the prothrombin gene mutation yielded conflicting results. Further large prospective studies are needed to asses the relative clinical and cost effectiveness of anticoagulant therapies in the prevention of pregnancy adverse outcomes.