This study focused on investigating the effects of dietary counseling on antioxidant intakes and how diet can influence reactive oxygen species (ROS) levels and consequently oxidative stress (OS) during pregnancy. At the end of the first trimester of pregnancy (12–13 week of pregnancy), 80 women were randomized into a control group and to an intervention group to receive individual dietary counseling. In the intervention group (n = 60), the dietary counseling about the Mediterranean diet (MD) was carried out during six online meetings every 15 days and focused on antioxidant nutrients and their intake. They were encouraged to follow the antioxidant-rich diet for 12 weeks, including increased consumption of antioxidant-rich foods such as ≥5 servings/day of vegetables, ≥2 servings/day of fruit, ≥8.5 servings/day of wholegrains and 3–4 servings/week of lean meat. In the control group (n = 20) dietary counseling included generic, standard of care guidance about nutrition in pregnancy and was only discussed during a single session. OS biomarkers, particularly (ROS) and Total Antioxidant Capacity (TAC) levels, were analyzed before and after the study duration in women’s serum. The results of the study showed lower ROS and higher TAC levels after intervention compared to the levels before intervention, as well as compared to the levels of the control group. In conclusion, dietary counseling improved the intake of antioxidant nutrients from food during pregnancy, as depicted by oxidative stress biomarkers’ levels, and may influence the observed impacts of these dietary patterns on pregnancy outcomes.

Pregnancy represents a period of heightened oxidative demand in which maternal metabolic adaptations are tightly regulated by redox-sensitive molecular pathways. Imbalances in these systems have been associated with gestational complications, impaired placental function, and long-term effects on offspring health. This review examines the molecular mechanisms through which adherence to the Mediterranean diet (MD) influences oxidative balance during pregnancy. We summarize evidence on how MD-derived bioactives regulate oxidative stress pathways and affect oxidative stress biomarkers, as well as the expression of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase. At the same time, certain MD foods containing environmental contaminants may potentially attenuate its protective effects. In addition, the review explores molecular insights into how the MD may counteract oxidative stress induced by environmental pollutants through modulation of redox signaling and detoxification pathways. By integrating biochemical, molecular, and environmental perspectives, this review highlights the MD as a potential nutrigenomic intervention to optimize oxidative balance, support healthy pregnancy outcomes linked to environmental pollution.