Objective To investigate the serum micro-ribonucleic acid-15a(miR-15a)and macrophage mi-gration inhibitory factor(MIF)levels and their relationship with adverse maternal and infant outcomes in pa-tients with gestational diabetes mellitus(GDM).Methods From January 2020 to December 2022,106 patients with GDM who underwent prenatal examination and gave birth in the Hengshui Fourth People's Hospital were selected as the experimental group.Another 106 healthy women who underwent pregnancy examination and delivered in a hospital during the same period were selected as the control group.Detection of serum miR-15a level by real-time fluorescent quantitative polymerase chain reaction and serum MIF levels were detected by enzyme-linked immunosorbent assay.Serum MIF and miR-15a levels were compared between the two groups,and the relationship between miR-15a and MIF levels and adverse maternal and infant outcomes in GDM patients was analyzed by multivariate Logistic regression.Results The serum levels of miR-15a and MIF in the experimental group were higher than those in the control group,the difference was statistically sig-nificant(P＜0.05).The age of patients with adverse maternal and infant outcomes in the experimental group was＞35 years old,the pre-pregnancy body mass index was＞24 kg/m2,the proportion of patients with ad-verse pregnancy history,poor blood glucose control and serum MIF and miR-15a levels were higher than those with good maternal and infant outcomes in the experimental group,and the differences were statistically sig-nificant(P＜0.05).Multivariate Logistic regression analysis showed that age＞35 years old,pre-pregnancy body mass index＞24 kg/m2,adverse pregnancy history,poor blood glucose control and serum miR-15a and MIF were all risk factors for adverse maternal and infant outcomes in the experimental group(P＜0.05).Conclusion Serum miR-15a and MIF levels are abnormally elevated in GDM patients,and serum miR-15a and MIF levels are closely related to adverse maternal and infant outcomes.