Obesity and gestational diabetes (GDM) are both increasing in occurrence and cause many problems both during pregnancy and beyond, predisposing the mother to development of type 2 diabetes and programming the offspring for obesity and diabetes, thus promoting a vicious cycle. Treatment of women with GDM reduces but does not prevent adverse outcomes. We have described reduced mitochondrial respiration and increased oxidative stress in the placenta of women with obesity and GDM which may be due to the altered maternal metabolic milieu of these conditions. The goal of this project is to define the substrates used for placental respiration and energy generation and identify the differences with obesity and GDM and how it relates to the metabolome and lipidome of these women. Finally, the team will employ novel mitochondrial-targeted antioxidants to improve mitochondrial respiration and placental function.