Oxidative stress is usually associated with prolonged intake of high-fat diet (HFD). However, little is known about the impact of maternal HFD on endogenous modulation of antioxidant-defence-enzyme-network, its link to adverse fetal growth and overall effects of Quercetin-3-o-rutinoside (QR) supplementation. Sprague-Dawley rats were initially assigned to normal diet (ND) or HFD for 8 weeks and mated. Post-conception, rats were further divided into four groups, of which two groups had diets supplemented with QR while others continued with their respective diets until delivery. Measurements include food and water consumption, physical parameters (body weight, body mass index (BMI) and fur appearance), oral glucose tolerance, lipid profiles, and placental/liver oxidative changes. We observed that water consumption was significantly increased in dams fed HFD without marked differences in food intake, body weight, BMI and glucose tolerance. Surprisingly, offspring of HFD-fed dams had reduced body weight marked by delayed fur appearance compared to the ND offspring. In dams, there were alterations in lipid profile. Lipid peroxidation was increased in the placenta and liver of gestational day (GD) 19 HFD-fed dams and their postnatal day (PND) 21 male offspring. There was evidence of HFD-induced nitrosative stress in dams and PND28 female offspring. Adaptive defence indicate decreased placenta and liver superoxide dismutase (SOD) levels as well as differential changes in total antioxidant capacity (TAC) and catalase (CAT) activity in HFD treated dams and their progenies. Overall, the results indicate that intrauterine metabolic alterations associated with maternal high-fat consumption may induce oxidative challenge in the offspring accompanied by mild developmental consequences, while QR supplementation has little or no beneficial effects.