Objective To investigate the influencing factors of adverse pregnancy outcomes in patients with preeclampsia and the predictive value of serum trace elements in the second trimester.Methods A total of 98 patients with preeclampsia admitted to Qujing First People's Hospital from January 2019 to June 2022 were enrolled in the study.Patients were divided into poor outcome group and good outcome group according to whether they had adverse pregnancy outcomes.The clinical data of all patients enrolled in the study were col-lected and the serum levels of trace elements calcium,copper,zinc and iron were detected in the second trimes-ter.Univariate analysis and multivariate Logistic regression were used to analyze the influencing factors of ad-verse pregnancy outcomes in patients with preeclampsia.The levels of serum trace elements in the second tri-mester of pregnancy were compared between the poor outcome group and the good outcome group.The re-ceiver operating characteristic(ROC)curve was used to evaluate the predictive value of serum trace elements calcium,copper,zinc and iron for adverse pregnancy outcomes in patients with preeclampsia.Results Univari-ate analysis showed that compared with the good outcome group,the poor outcome group had significantly higher systolic blood pressure,24 h urinary protein quantitation,and D-dimer level(P＜0.05)and significantly less gestational age and platelet count at admission(P＜0.05).Multivariate Logistic regression analysis showed that 24 h urinary protein quantification,D-dimer and platelet count were the influencing factors of ad-verse pregnancy outcomes in patients with preeclampsia(P＜0.05).The levels of serum trace elements calci-um,copper,and zinc in the poor outcome group were significantly lower than those in the good outcome group(P＜0.05),and the level of iron was significantly higher than that in the good outcome group(P＜0.05).ROC curve analysis showed that the areas under the curves(AUCs)of serum calcium,copper,zinc,and iron in the second trimester of pregnancy for predicting adverse pregnancy outcomes in preeclampsia patients were 0.830(95％CI:0.780-0.880),0.855(95％CI:0.805-0.905),0.847(0.797-0.897)and 0.861(95％CI:0.811-0.911),respectively.Conclusion Adverse pregnancy outcomes in patients with preeclampsia are re-lated to 24 h urine protein,D-dimer and platelet count.The levels of serum trace elements calcium,copper,zinc and iron in the second trimester of pregnancy change significantly in patients with adverse pregnancy out-comes,which may become predictive markers of adverse pregnancy outcomes.