Abstract Body (Do not enter title and authors here): Introduction: Gestational diabetes mellitus is increasingly recognized as a risk factor for adverse fetal cardiovascular remodeling. Hyperglycemia during pregnancy may lead to altered fetal myocardial development, particularly affecting septal thickness and myocardial function. However, standardized fetal cardiac markers and the magnitude of these changes remain under-investigated.

Hypothesis: We hypothesized that fetuses of mothers with GDM exhibit statistically significant increases in interventricular septal thickness and impaired cardiac function compared to fetuses of normoglycemic mothers during the third trimester.

Methods: A prospective cohort study was conducted involving 120 pregnant women diagnosed with GDM and 120 matched normoglycemic controls between 28–34 weeks of gestation. All participants underwent fetal echocardiography using standardized M-mode and Doppler measurements. Parameters assessed included IVST, left ventricular myocardial performance index, and E/A ratio. Maternal HbA1c levels were measured concurrently. Statistical analysis was performed using SPSS with independent t-tests and Pearson correlation coefficients; p-values < 0.05 were considered statistically significant.

Results: Fetuses in the GDM group exhibited significantly increased IVST (mean ± SD: 4.83 ± 0.45 mm) compared to controls (3.97 ± 0.51 mm), p < 0.001. The myocardial performance index was also elevated in the GDM group (0.55 ± 0.06) versus controls (0.48 ± 0.05), p < 0.001, indicating impaired global myocardial function. A moderate positive correlation was observed between maternal third-trimester HbA1c and fetal IVST (r = 0.58, p < 0.01), and a negative correlation with E/A ratio (r = –0.41, p < 0.05), suggesting diastolic dysfunction.

Conclusion: Third-trimester fetuses of GDM mothers demonstrate statistically significant myocardial hypertrophy and impaired cardiac function. These findings support the use of fetal echocardiography in GDM pregnancies to enable earlier identification of cardiometabolic risk. Glycemic control, as indicated by maternal HbA1c, appears moderately correlated with the severity of fetal cardiac remodeling.