Objective To explore the causal association between coagulation function,including von Willebrand factor(vWF),a disintegrin and metalloproteinase with thrombospondin type 1 motif,member 13(ADAMTS13),activated partial thromboplastin time(aPTT),coagulation factor Ⅷ(FⅧ),coagulation factor Ⅺ(FⅪ),coagulation factor Ⅶ(FⅦ),coagulation factor Ⅹ(FⅩ),endogenous thrombin potential(ETP),plasminogen activator inhibitor-1(PAI-1),protein C,and plasmin,and gestational diabetes mellitus(GDM)using two-sample two-way Mendelian randomization(MR),and to provide genetic evidence for the association between coagulation function and the pathogenesis of GDM.Methods The IEU OpenGWAS database was accessed using the R package TwoSampleMR(v 0.5.6)to obtain the statistical data of the genome-wide association study(GWAS)summary of GDM.MR analysis of the causal association between 11 coagulation function and GDM was performed by the inverse-variance weighted method(IVW),the MR-Egger method,and the weighted median method(WM).Results In this study,the GWAS summary statistics of GDM(covering 5687 cases and 117892 controls)were used for MR analysis.It was found that there was a causal relationship between the predicted plasma FⅧ level and the risk for GDM(IVW:[odds ratio,OR]=0.28,95%confidence interval[CI]:0.10-0.75,P＜0.001;WM:OR=0.30,95%CI:0.09-0.98,P＜0.001).There was no causal relationship between other coagulation function and the risk for GDM(P＞0.05).Conclusion There is a significant causal relationship between the plasma FⅧ level and the risk for GDM.This finding highlights the complex interaction between coagulation function and glucose metabolism during pregnancy,but further research on this finding is warranted.