Comparison of Doppler Indices in Diabetic and Non-Diabetic Populations during the Third Trimester of Pregnancy

Open Access

Abstract

Background: Maternal diabetes mellitus is associated with altered placental function and adverse perinatal outcomes. Doppler ultrasonography provides a non-invasive method for assessing uteroplacental and fetal hemodynamics, particularly during the third trimester when circulatory adaptations are most pronounced. Aim of the study: To compare umbilical artery (UA), middle cerebral artery (MCA), and cerebroplacental ratio (CPR) Doppler indices in diabetic and non-diabetic pregnant women during the third trimester. Methods & Materials: This hospital-based comparative cross-sectional study included 100 third-trimester pregnant women (≥32 weeks of gestation), comprising 50 diabetic and 50 non-diabetic participants. Doppler ultrasonography was performed to measure UA and MCA systolic/diastolic (S/D) ratio, resistance index (RI), pulsatility index (PI), and CPR. Data were analyzed using SPSS version 26.0, and intergroup comparisons were made using independent sample t-tests and chi-square tests, with a p-value <0.05 considered statistically significant. Result: Diabetic pregnancies demonstrated significantly higher UA S/D ratio, RI, and PI compared with non-diabetic pregnancies (p <0.001 for all). Conversely, MCA Doppler indices (S/D ratio, RI, and PI) were significantly lower in the diabetic group (p ≤0.01). The mean CPR was significantly reduced in diabetic pregnancies (1.14 ± 0.26 vs. 1.52 ± 0.31; p <0.001), and abnormal CPR (<1.1) was more frequent among diabetic women (36.0% vs. 12.0%; p = 0.006). Overall, abnormal Doppler findings were significantly more prevalent in diabetic pregnancies. Conclusion: Diabetes in pregnancy is associated with significant alterations in fetal Doppler indices during the third trimester, reflecting increased placental resistance and fetal circulatory redistribution. Routine Doppler surveillance may help identify high-risk diabetic pregnancies and guide timely clinical intervention.