Exposure and outcome variables
We extracted clinical and laboratory data from the electronic medical records using the case information management system at Shengjing Hospital, China Medical University. These include maternal age, plasma TAFI levels, maximum platelet aggregation rate (including ADP, Arachidonic acid [AA]), coagulation measurements (prothrombin time [PT], prothrombin time activity [PTA], activated partial thromboplastin time [APTT], fibrinogen content [FIB], Thrombin clotting time [TT], D-dimer), blood cell tests (lymphocyte percentage [LYMPH], monocyte percentage [MONO], basophil percentage [BASO], Red cell distribution width -CV value [RDW-CV], Red cell distribution width -SD value [RDW-SD]), thyroid function tests (free triiodothyronine [FT3], free thyroxine [FT4], thyroid stimulating hormone [TSH], thyroid peroxidase antibodies [Anti-TPO], thyroglobulin antibody [Anti-TG]), thromboelastography tests (reaction time [R], clotting time [K], Angle, maximum amplitude [MA], coagulation index [CI], estimated percentage of lysis [EPL], lysis after 30 min [LY30]). In this study, we measured plasma TAFI using an ELISA assay with an AU480 fully automated biochemical analyzer from Beckman Coulter, USA, and a TAFI quantitative assay kit from Liaoning Mediatek Biotechnology Co. Normal range of plasma TAFI reference hospital plasma TAFI normal range: 24-35ug/mL.