The potential use of LMWH in pregnant women with APS has been verified by many investigations, and the treatment during pregnancy is recommended by international professional guidelines; however, the same cannot be stated for inherited thrombophilia such as factor V Leiden; prothrombin G20210A mutation; and deficiencies of antithrombin, protein C, or protein S. All of these thrombophilias are also associated with pregnancy loss [143,144,145,146]. Here, PROS1 is linked to thrombophilia.