Abstract： Objective:To investigate the characteristics of fetal cardiac dysfunction in monochorionic diamniotic(MCDA)twin pregnancies,and establish a prediction model for their perinatal outcomes mainly based on ultra-sound indicators using information method.Methods:A total of 104 twin cases with ultrasound indicating fetal heart abnormalities were selected.Based on their chorionic and fetal heart abnormalities,they were divided into three groups:MCDA dysfunction group(61 cases),MCDA structural abnormalities group(23 cases),and dichori-onic diamniotic(DCDA)structural abnormalities group(20 cases).The clinical features of the three groups were analyzed and compared,and clinical outcomes were followed up until 3 years postpartum.A perinatal outcome prediction model for fetal cardiac dysfunction was established using the information method.All ultrasound abnor-mal indicators(7 categories)from the MCDA functional abnormality group,as well as 3 common clinical indicators,were included in the information model calculation.At the same time,the effectiveness of the model prediction was evaluated using receiver operating characteristic(ROC)curves and reserved cases(5 cases).Results:① Com-pared with the group with MCDA structural abnormalities,the group with MCDA functional abnormalities had a higher proportion of twin specific complications and a more severe staging.There was no statistically significant difference(P>0.05)in the proportion of live and non-live birth among the three groups,as well as the differences between different live birth outcomes and non-live birth outcomes.However,follow-up found that the majority(22/24)of live births in the MCDA dysfunction group had their heart function returning to normal on their own.②The pre-diction results of the information model showed that the classification criteria for adverse perinatal outcome or risks(I)of fetal cardiac dysfunction were:when I>1.0,the risk of fetal death was high;when-1.0<I≤1.0,the risk of fetal death was moderate;;when I≤-1.0,the risk of fetal death was low.③The ROC curve validation results show that the AUC was 0.864(95% CI 0.767-0.961).The validation results of the reserved case test showed a high degree of agreement with the actual clinical outcomes.Conclusions:The outcome prediction model based on the information method has a certain correlation with the hemodynamic mechanism of fetal cardiac dysfunc-tion,which has high value in predicting the risk of fetal death due to MCDA cardiac dysfunction.