To explore morphological and structural effects of pregestational diabetes on the umbilical vein to provide a theoretical basis for fetal development in comparison to normal pregnancy. A prospective case–control observational study was done on 100 pregnant women who visited Al-Zahraa University Hospital. Their gestational ages varied from 28 to 40 weeks, while their ages ranged from 20 to 40. During the period from January 2021to December 2021. The chosen topics were split into two groups: Group I [control group] (n=50) consisted of 50 healthy pregnant women without any complication or any medical disorders. [Study group] Group II (n=50): This group consisted of 50 pregestational diabetic pregnant women (Type 1 and Type 2). Sonography was used to determine the diameter of the umbilical cord and the diameters of the umbilical veins, as well as the surface area of Wharton's jelly. A total of 100 formalin-fixed and paraffin-embedded specimens were gathered and prepared. In this research, there was a greatly statistically relevant variance in umbilical cord diameter (p=0.000), umbilical artery diameter (p = 0.000), umbilical vein diameter (p= 0.000), and Wharton's jelly between the two groups (p 0.000). Microscopic study of diabetic UC samples showed considerable Wharton's Jelly bleeding next to a vein, perivascular and intraparietal hemorrhage with wall dissection. The UC vein of diabetic samples showed dilatation and hemorrhage compared to that of control group. Measurements of umbilical cord, umbilical vein and umbilical arteries diameter and Wharton's jelly surface area can be used as an additional sonographic tool for assessing maternal and fetal health.