Context The Developmental Origins of Health and Disease (DOHaD) concept suggests that early-life interventions significantly influence the long-term health outcomes of offspring. Emerging evidence supports that maternal physical exercise and balanced nutrition can positively impact the health of the next generation. Aims This study investigated the effects of maternal swimming combined with postnatal high-fat, high-sugar (HFHS) diet on the ovarian health of adult female Wistar rat offspring. Methods Adult female Wistar rats performed swimming exercise in a controlled temperature environment (32°C, 2% bodyweight overload adjusted daily) during 4weeks, starting 1week prior mating. The female offspring received a control or HFHS diet from postnatal day (PND) 21 to PND 90. We analyzed offspring's body weight, ovarian histomorphology, redox status, and associated molecular pathways 5' adenosine monophosphate-activated protein kinase (AMPKα), forkhead box O3 (FoxO3), and mitofusin 1 (Mfn-1). Key results Our findings reveal that maternal swimming exerted an effect on offspring body weight gain, delaying it. Individually, maternal exercise reduced superoxide dismutase (SOD) activity and mitofusin-1 levels, while the postnatal HFHS diet alone decreased both SOD and glutathione peroxidase (GPx) activities and increased the pFOXO3a/FOXO3a ratio in the ovaries. Conclusions We showed that combination of maternal swimming with a 2% overload and a postnatal HFHS diet can negatively affect the ovarian redox balance in offspring. Implications Prenatal and postnatal lifestyle might affect reproductive function in females.