Plasma Markers of Oxidative Stress in Patients with Gestational Diabetes Mellitus in the Second and Third Trimester.

To determine plasma markers of oxidative stress during the second and third trimester of pregnancy in patients with gestational diabetes mellitus (GDM). We conducted a prospective nested case-control study involving 400 pregnant women, 22 of whom developed GDM. As control group, 30 normal pregnant women were chosen randomly. Plasma samples were analyzed for 8-iso-prostaglandin F2 (8-iso-PGF2), advanced oxidative protein products (AOPPs), protein carbonyl (PCO), glutathione peroxidase-3 (GPX-3), and paraoxonase-1 (PON1) at 16-20 weeks, 24-28 weeks, and 32-36 weeks of gestation. Compared to control subjects, the plasma levels of PCO, AOPPs, and 8-iso-PGF2 were elevated at 16-20 weeks' and 32-36 weeks' gestation in GDM. There was no significant difference in PCO and 8-iso-PGF2 at 24-28 weeks in GDM. GPX-3 was statistically significantly increased at 16-20 weeks and 32-36 weeks in GDM. PON1 reduced in patients with GDM. No significant differences were found at 24-28 and 32-36 weeks between the GDM and control groups. In GDM, PCO, AOPPs, and 8-iso-PGF2 levels were higher and GPX-3 and PON1 levels were lower in the second than the third trimester. Oxidation status increased in GDM, especially protein oxidation, which may contribute to the pathogenesis of GDM.