 Recurrent pregnancy loss is a well-described complication of the antiphospholipid antibody syndrome and is thought to be associated with thrombosis of placental vessels, often with evidence for placental infarction. More recently, inherited thrombophilic abnormalities have been linked to RPL and other obstetric complications. At least 16 case-control studies found a high prevalence of factor V Leiden FVL in women with unexplained RPL up to 30 compared to 1 to 10 of control subjects with odds ratios ranging from 2 to 5 Press et al. 2002. Likewise, other thrombophilic risk factors including factor II G20210A, hyperhomocysteinemia, protein C, protein S and antithrombin deficiencies have also been associated with RPL Sanson 1996; Brenner 1999. 