Maternal obesity has been shown to impair the oxidative status in the placenta and newborns, potentially leading to adverse pregnancy outcomes and long-term effects on the programming of offspring metabolic status. This study aimed to investigate the impact of maternal obesity on maternal and umbilical cord plasma oxidative status, as well as placental oxidative adaptation. Maternal obesity (n = 20), defined as a pre-pregnancy BMI ≥ 25 kg/m², and maternal leanness (n = 20), defined as a pre-pregnancy BMI < 23 kg/m², were the group categories used in this study. Both groups were matched according to gestational age at delivery. Maternal blood, umbilical cord blood, and placental tissue were collected to assess nutritional content (cholesterol, triglyceride, and protein), oxidative stress markers (MDA and protein carbonyl), and antioxidant activity (SOD and catalase). Placental protein expression (SOD2, catalase, UCP2, and Nrf2) was evaluated using Western blot analysis. Catalase activity in maternal plasma significantly increased in the maternal obesity group (p = 0.0200), with a trend toward increased MDA and protein carbonyl levels. In umbilical cord plasma, triglyceride, protein carbonyl, and catalase activity were significantly elevated in the maternal obesity group compared with the lean controls (p = 0.0482, 0.0291, and 0.0347, respectively). Placental protein expression analysis revealed significantly decreased SOD2 (p = 0.0011) and catalase (p < 0.0001), along with Nrf2 downregulation (p < 0.0001). An increase in mitochondrial antioxidant UCP2 expression was observed (p = 0.0117). The neonatal protein carbonyl levels positively correlated with placental protein carbonyl (r = 0.7405, p < 0.0001) and negatively correlated with maternal catalase activity (r = −0.4332, p = 0.0052). This study thus provides evidence that maternal obesity is associated with placental and fetal oxidative stress, alongside a concurrent increase in placental antioxidant UCP2 expression.

Maternal obesity has been found to be impaired oxidative status in placenta and newborn which can lead to adverse pregnancy outcomes and long-term adverse influence on metabolic programming in the offspring. This study aimed to investigate the role of maternal obesity on maternal and umbilical cord plasma oxidative status and placental oxidative adaptation. Maternal obesity (n=20) defined as pre-pregnancy BMI ≥ 25 kg/m² and maternal lean (n=20) defined as pre-pregnancy BMI < 25 kg/m² were recruited into this study. Both groups were matched by gestational age at delivery. Maternal blood, umbilical cord blood and placental tissue were collected to assess nutritional content (cholesterol, triglyceride, and protein), oxidative stress marker (MDA and protein carbonyl) and antioxidant activity (SOD and catalase). Placenta protein expression (SOD2, catalase, UCP2 and Nrf2) was evaluated by western blot analysis. Catalase activity in maternal plasma significantly increased in maternal obesity group (p = 0.0200) with an increased trend in MDA and protein carbonyl levels. Umbilical cord plasma triglyceride, protein carbonyl and catalase activity significantly increased in maternal obesity compared with that in maternal lean (p = 0.0462, 0.0485, and 0.0348, respectively). Although placenta protein expression analysis exhibited significant decreased SOD2 (p = 0.0169) and catalase (p = 0.0067), accompanied by Nrf2 downregulation (p = 0.0453). An increased mitochondrial antioxidant UCP2 expressions was observed (p = 0.0143). Hence, our study provided evidence that maternal obesity is associated with placental and fetal oxidative stress with the parallel increased placental antioxidant UCP2 expression.