Assessment of Maternal–Fetal Redox Balance in Gestational Diabetes Mellitus: A Cross-Sectional Study

<b>Background/Objectives</b>: Gestational diabetes mellitus (GDM) is one of the most common metabolic complications of pregnancy and is linked to long-term metabolic and cardiovascular risks for both mother and child. Its pathophysiology includes increased generation of reactive oxygen species (ROS) and/or decreased antioxidant defenses; nonetheless, the redox dynamics between mother and fetus are still poorly understood. Our goal was to assess oxidative stress (via derivatives of reactive oxygen metabolites, d-ROMs) and antioxidant capacity (via biological antioxidant potential, BAP) in maternal, umbilical cord, and neonatal blood from women with GDM compared to normoglycemic controls, and to investigate potential associations with clinical and neonatal outcomes. <b>Methods</b>: In this single-center cross-sectional study, 56 women with GDM and 52 matched controls provided maternal venous, umbilical cord, and neonatal blood samples at delivery. Plasma d-ROMs and BAP were measured using colorimetric assays. Clinical and neonatal outcome data were collected. <b>Results</b>: Women with GDM had considerably higher maternal d-ROM levels compared to both the umbilical cord and neonatal compartments. BAP measurements revealed that maternal blood had the lowest antioxidant capacity, while cord and newborn samples had higher levels. GDM mothers had significantly greater maternal d-ROMs and lower BAP compared to controls (both <i>p</i> < 0.05). There were no differences in cord blood d-ROMs or BAP between the GDM and the control group. The maternal BAP/d-ROM ratio decreased significantly in the GDM group (<i>p</i> < 0.01), but the cord ratio remained constant. Notably, neither maternal nor neonatal redox indicators were related to perinatal outcomes, indicating a limited prognostic potential for unfavorable neonatal occurrences. <b>Conclusions</b>: GDM is associated with increased maternal oxidative stress and decreased antioxidant capacity, with no substantial changes in newborn redox status. Redox indicators did not predict perinatal issues across this group. These findings demonstrate the need for larger prospective research to determine whether early changes in redox balance can predict the development of GDM or unfavorable outcomes.