Abstract： Objective:To investigate the predictive value of pregnancy-associated plasma protein A(PAPP-A),fasting blood glucose(FPG),body mass index(BMI)and age in gestational diabetes mellitus(GDM)during the first trimester.Methods:A retrospective analysis was performed on 792 pregnant women who underwent pre-natal examination and delivered in Sichuan Provincial Maternal and Child Health Care Hospital from December 2021 to June 2022.They were divided into GDM group(232 cases)and control group(560 cases)according to whether they had GDM.The clinical data,serum PAPP-A median multiple(PAPP-A MoM)in early pregnancy and FPG levels were compared between the two groups.The indicators with statistical significance in univariate analy-sis were included in multivariate Logistic regression analysis to analyze the related factors affecting the occurrence of GDM.The receiver operating curve(ROC)and area under the curve(AUC)of different indexes were plotted to compare the efficacy of GDM prediction.Results:①The age,pre pregnancy BMI,early pregnancy FPG and the proportion of assisted reproductive technology in GDM group were higher than those in control group,and the differences were statistically significant(P＜0.05).The early pregnancy PAPP-A MoM level in GDM group was lower than that in control group,and the difference was statistically significant(P＜0.05).②Multivariate Logistic regression analysis showed that older age,lager pre-pregnancy BMI and lager FPG in the first trimester were in-dependent risk factors for GDM occurrence(OR＞1,P＜0.05),while an increase of PAPP-A MoM in the first tri-mester was a protective factor(OR＜1,P＜0.05).③ROC showed that the combination of PAPP-A MoM in early pregnancy,FPG in early pregnancy,BMI in pre-pregnancy and age had the highest AUC(0.752)when predicting GDM,with a sensitivity of 55.6％and a specificity of 84.3％.Conclusions:The combined screening of serologi-cal(PAPP-A +FPG)and clinical data(pre-pregnancy BMI +age)in early pregnancy has a high clinical application prospect and can be popularized.