Hypofibrinogenemia and the α-Fibrinogen Thr312Ala Polymorphism may be Risk Factors for Early Pregnancy Loss.

We analyzed a cohort of 36 females with pregnancy loss. In addition to 11 patients with antiphospholipid antibody syndrome and 2 patients with congenital antithrombin (AT) or protein C deficiency, we identified 5 patients with low fibrinogen levels (median 110 mg/dL) prior to 10 weeks of gestation. Four of these 5 patients underwent a fibrinogen gene analysis, and all 4 were found to be heterozygotes for the α-fibrinogen (FGA) Thr321Ala polymorphism. One female without hypofibrinogenemia with a history of 8 pregnancy losses was found to be homozygous for the same polymorphism, and she also showed hypercoagulability without thrombosis. In conclusion, there was a relatively high frequency of pregnancy loss in the setting of hypofibrinogenemia and/or the FGA Thr312Ala polymorphism, and this may be an important risk factor for pregnancy loss and a hypercoagulable state in later pregnancy.