Background/Objective: This study is aimed to assess the link between oxidative stress markers and incident hyperglycemia in women with gestational diabetes mellitus (GDM) during an educational intervention. Methods: The study used a prospective cohort. Pregnant women with GDM who were 18–40 years old (n = 201) participated in an 18-month postpartum educational intervention emphasizing healthy practices (nutrition, breastfeeding, physical activity, and psychosocial support). GDM women were tested with an oral glucose tolerance test (OGTT) after the third month postpartum, and were classified as follows: (1) incident hyperglycemia (IHypergly) (n = 86) if they had a fasting plasma glucose (FPG) of 100–125 mg/dL, and impaired glucose tolerance of 2 h (140–199 mg/dL), or type 2 diabetes (T2D) with an FPG ≥ 126 or ≥200 mg/dL (2 h); and (2) without incident hyperglycemia (n = 115) if they had an FPG < 100 mg/dL and <140 mg/dL 2 h post-OGTT. Participants were evaluated at the end of pregnancy and post-intervention. Clinical, biochemical, anthropometric, dietary, and oxidative stress markers data (malondialdehyde, reduced glutathione, antioxidant capacity, carbonylated proteins, and adiponectin) were recorded. Multivariate logistic regression analysis identified an association between oxidative stress markers and incident hyperglycemia in women with GDM. Results: A total of 6% progressed to T2D, and 36.8% to prediabetes. At baseline, Ihypergly women exhibited elevated oxidative stress markers and adiponectin, and lower antioxidant capacity. Post-intervention, they showed higher antioxidant capacity, GSH, and adiponectin, and lower MDA. Basal malondialdehyde, pregestational BMI, HbA1c, and sugary food consumption positively correlated with Ihypergly. A high intake of antioxidants inversely correlated with incident hyperglycemia. Conclusions: Higher concentrations of plasma markers of oxidative stress are associated with postpartum incident hyperglycemia in women with gestational diabetes.

Background/Objectives: This study aimed to assess the associations between the Lifestyle Inflammation Score (LIS) and gestational diabetes mellitus (GDM), and glucose metabolism alterations (GMA) postpartum. Methods: A secondary analysis was conducted on 378 pregnant women at the end of pregnancy. Anthropometric, clinical, biochemical, and dietary parameters were evaluated. Postpartum reclassification was based on fasting serum glucose (>100 mg/dL), HbA1c (>5.7%), and/or a 2-h oral glucose tolerance test (>140 mg/dL). The LIS was calculated using a proxy index including smoking status, physical activity, and pregestational BMI, applying the beta coefficient from the original LIS model. Tertiles were created, with T3 indicating the highest level of proinflammatory exposure. Statistical analyses included Kruskal–Wallis, one-way ANOVA, linear-by-linear association, and multivariate logistic regression, adjusted for family history, gestational weight gain, carbonylated proteins, and adiponectin to evaluate associations between LIS and GDM, and adjusted for pharmacological treatment, gestational weight gain, and breastfeeding for LIS and GMA. Results: Higher LIS values were more common among women with GDM (T1 = 45.9%, T2 = 62.2%, T3 = 74.8%, p < 0.001) and among those with GMA (T1 = 34.4%, T2 = 45.6%, T3 = 53.7%, p = 0.019). Compared with the lowest tertile, the highest tertile of LIS was associated with greater odds of GDM (OR 3.72; 95% CI: 1.19–11.64, p = 0.024) and GMA (OR 2.69; 95% CI: 1.25–5.76, p = 0.011). Conclusions: A more proinflammatory lifestyle, as reflected by a higher LIS, increases the risk of progression to GDM and later to GMA.