Evaluation of the Relationship Between the Thymic–Thoracic Ratio and Perinatal Adverse Outcomes in Fetuses with Congenital Heart Defects

OBJECTIVES: The aim of this study was to evaluate the thymic-thoracic ratio (TTR) in fetuses with congenital heart defects (CHD) and to investigate the association between TTR and adverse perinatal outcomes. METHODS: This prospective study was conducted at a tertiary care center. A total of 85 participants were enrolled, including 42 fetuses with CHD and 43 healthy controls between 18 and 37 gestational weeks. The TTR was calculated for each case. First, outcomes were compared between the CHD and control groups; subsequently, CHD cases were analyzed in subgroups. Receiver operating characteristic (ROC) analysis was performed to assess the relationship between TTR and perinatal outcomes in the CHD group. RESULTS: TTR was significantly lower in the fetal CHD group compared with controls (p < .001). In the conotruncal CHD subgroup, TTR values were also significantly lower (p < .001). In the Spearman correlation analysis performed for neonatal intensive care unit (NICU) admission between the study and control groups, TTR showed a negative correlation with NICU admission (r = -0.331, p = .002). ROC analysis indicated that the optimal TTR cut-off value for predicting NICU admission was 0.41, with 72% sensitivity and 62% specificity (AUC = 0.729; p < .001). CONCLUSION: TTR was lower in fetuses with CHD. A decreasing TTR was associated with an increased rate of adverse perinatal outcomes. Assessment of TTR in fetuses with CHD may be a useful tool for predicting adverse perinatal outcomes.