The results of our study revealed that there was no significant differencein HgA1C in diabetic patients with and without umbilical artery resistance index≥95th percentile.The abnormal UA RI, MCA RI and MCA/UA RI may be usefulparameters in predicting adverse perinatal outcome in diabetic pregnancies associated with hypertension. On the other hand, there were weak correlations between abnormal UA RI, MCA RI and MCA/UA RI and adverse perinatal outcome of diabetic pregnancies not associated with hypertension.Fetuses of diabetic mothers in group 1 (pre-existing diabetes) and group 3 (diabetes associated with hypertension) have impairment of diastolic function compared with fetuses of non-diabetic mothers.In our study, none of the neonates in the diabetic groups developedcongestive heart failure or ventricular outflow obstruction, indicating thatmyometrial hypertrophy was not severe enough to induce these complications.