Objective To investigate the value of serum miR-148b and miR-375 levels combined with prenatal ultrasound in the diagnosis of fetal congenital heart disease(FCHD)by the measurement of microRNA(miR)-148b and miR-375 levels.Methods Totally 106 pregnant women with suspected FCHD who underwent prenatal screening in our hospital from January 2019 to January 2023 were enrolled.They were assigned into a case group(FCHD,n=80)and a control group(non-FCHD,n=26)based on postpartum follow-up.The levels of serum miR-148b and miR-375 were compared between the two groups.The receiver operating characteristic(ROC)curve was plotted to analyze the diagnostic efficacy of serum miR-148b and miR-375 for FCHD.The four grid table was applied to analyze the diagnostic efficacy of prenatal ultrasound combined with serum miR-148b and miR-375 levels for FCHD.Results The serum miR-148b level in the case group was significantly decreased than that in the control group,while the serum miR-375 level was significantly increased(P<0.05).The accuracy,sensitivity,and specificity of prenatal ultrasound combined with serum miR-148b and miR-375 in diagnosing FCHD were 93.40%,92.50%,and 96.15%,respectively.The sensitivity of the combined diagnosis was higher than that of serum miR-148b and miR-375 alone(P<0.05),the accuracy and specificity of the combined diagnosis were higher than those of prenatal ultrasound,serum miR-148b,and miR-375 alone(P<0.05).Conclusion FCHD have significantly reduced serum miR-148b level and increased serum miR-375 level.Prenatal ultrasound combined with serum miR-148b and miR-375 has high diagnostic value for FCHD.