iarmsIARMSIARMS2709-3255https://doi.org/10.47310/iarjms.2026.v07i01.002Evaluation of Fetal Thymic Thoracic Ratio in pregnancies complicated with PreeclampsiaObjective: Preeclampsia is a serious hypertensive disorder of pregnancy and a leading cause of maternal and perinatal morbidity and mortality. Its exact etiology remains unclear, though immunological factors are implicated. Emerging evidence suggests the fetal thymic thoracic ratio (TTR) may serve as a novel marker for predicting preeclampsia. Aim of the Study: To investigate the relationship between fetal TTR and preeclampsia, and to assess its association with disease severity. Patients and Methods: This case control study was conducted at the Department of Obstetrics and Gynecology, Al Elwiya Maternity Teaching Hospital, between January 2024 and January 2025. A total of 200 third trimester pregnant women were enrolled: 100 with preeclampsia and 100 healthy controls. Preeclamptic cases were subdivided into mild and severe groups. Maternal demographic, clinical, and ultrasound data were collected. Fetal TTR was measured and analyzed for its diagnostic utility in predicting severe preeclampsia. Results: Fetal TTR was significantly lower in preeclamptic pregnancies compared with controls, with the greatest reduction in severe cases. Mean fetal TTR was 0.362±0.024 in severe preeclampsia, 0.394±0.014 in mild cases, and 0.425±0.03 in controls (p<0.001). Receiver operating characteristic (ROC) analysis confirmed strong predictive value, with an area under the curve of 0.921. A cutoff of 0.396 yielded 90% sensitivity and 71.3% specificity. Conclusion: Fetal TTR decreases significantly in preeclampsia, particularly in severe disease. Its clinical integration may enhance early detection and management, offering a valuable tool for assessing disease severity.