Obesity is one of the most concerning health issues in the modern world, especially due to its association with greater risk of developing a wide range of chronic diseases. Pre-gestational obesity may increase the chances of maternal and fetal morbimortality, such as gestational diabetes mellitus, preeclampsia, macrosomia and, even, fetal death. It may also lead to long term disorders, enhancing the risk of excessive adiposity and metabolic syndrome in later life and, thus, contributing to the maintenance of the obesity cycle and its health effects through the subsequent generations. Alterations in placental function are thought to be deeply involved in this scenario, however further research on its molecular and biological mechanisms is needed. During pregnancy, there is a physiological enhancement of the inflammatory state, marked by higher circulating cytokines and macrophage placental infiltration, which favors fetal nutrient supply and adequate growth; however, this response is exacerbated in women with pre-pregnancy obesity, leading to adverse outcomes. In this context, interventions aiming to reduce excessive inflammation may prevent or minimize the negative impact of pre-pregnancy obesity on both maternal and offspring's health. There is strong evidence suggesting an important role of n-3 LC-PUFA (EPA and DHA) on the attenuation and resolution of inflammatory states, besides influencing maternal lipid profile, fetal and infant adipogenesis and neurodevelopment. Additionally, the consumption of probiotic supplements during gestation seams to promote adequate maternal weight gain and improve the profile of inflammatory molecules secreted in the milk. Therefore, the nutritional interventions with fish oil, as a source of EPA and DHA, or probiotics, in women with pre-pregnancy obesity, may change the intrauterine environment and reduce the risk of both short and long term metabolic disorders. This study aims to investigate the metabolic and molecular changes promoted by gestational obesity and evaluate the effectiveness of different dietary interventions (fish oil or probiotic) on preventing or minimizing such alterations. We expect to contribute to the understanding of the physiological and molecular mechanisms underlying maternal obesity and its association with adverse pregnancy outcomes, associated with increased risk of chronic diseases in adulthood.