Abnormal carbohydrate metabolism during pregnancy : association with endothelial dysfunction

To evaluate whether abnormal endothelial function, a common finding in premenopausal women with type 2 diabetes, is present in early states of diabetes during pregnancy, such as impaired glucose tolerance (IGT) and gestational diabetes mellitus (GDM).

Brachial artery flow-mediated dilatation (FMD) (endothelium-dependent) and nitrate-induced dilatation (NID) (endothelium-independent) were measured in 23 pregnant subjects with carbohydrate abnormalities (10 IGT, 13 GDM) and in 15 pregnant control subjects during the third trimester of gestation. High-resolution vascular ultrasonography was used to perform these investigations. A fasting lipid panel was obtained, and glucose and insulin values in response to a 100-g oral glucose load were also measured.

FMD was significantly reduced in both groups of women with abnormal carbohydrate metabolism compared with control subjects (7.6 +/- 1.1% in the IGT group and 4.1 +/- 0.9% in the GDM group vs. 10.9 +/- 1.1% in control subjects, P < 0.04 and P < 0.0001, respectively). Significant difference in FMD was also observed between IGT and GDM groups (P < 0.04). NID was comparable in the three groups. Among all subjects, FMD showed a strong independent negative correlation with glycemic area (r=-0.60, P < 0.0001).

Endothelial dysfunction, an early marker of macrovascular disease, is present in pregnancies complicated by IGT and GDM. This alteration, which seems to be directly related to glycemic levels, could explain, at least in part, the increased risk for concurrent hypertensive disorders during pregnancy in these women.