Structural-tridimensional study of yolk sac in pregnancies complicated by diabetes

Objectives: To assess by two- and three-dimensional ultrasound the diameter and volume of the yolk sac in pregnant women affected by type 1 diabetes during the first trimester of pregnancy. Methods: 18 women affected by insulin-dependent diabetes mellitus (IDDM) and 52 normoglycemic pregnant women (controls) were enrolled in this study. The women were evaluated once a week (5-12 weeks of pregnancy). Ultrasound examination in all pregnant women was initially performed in a bidimensional fashion with a transvaginal 6.5-MHz probe and subsequently using a three-dimensional technique. Results: In the pregnant diabetic women the diameter of the yolk sac was significantly higher than that of controls in the first weeks of pregnancy, reaching a maximum diameter at 9 weeks, and decreasing thereafter, earlier than controls. The volume of the yolk sac increased in both groups from 5 weeks of pregnancy and reached maximum values at 10 weeks in both groups. The volumetric increase and decrease after reaching highest values were greater in IDDM patients. Conclusion: The clinical and diagnostic implications of the results of this study are still to be defined. Such a diagnostic technique may prove to be an additional element in monitoring diabetic women during early pregnancy.