A healthy in utero environment is essential for achieving optimal outcomes for women and their children. Gestational weight gain (GWG) has been shown to impact current and future maternal-infant health outcomes. Suboptimal weight gain during pregnancy (defined by the Institute of Medicine GWG guidelines) has been linked to several complications and is implicated in the inter-general cycle of obesity. Understanding contributors to GWG and intervening during pregnancy with healthy behaviour strategies may have a multi-generational effect for chronic disease prevention. The objective of the first study of this thesis was to examine the association between i) eating habits during pregnancy, ii) advice from family or friends about GWG, and iii) personal effort to stay within weight gain limits, and meeting GWG recommendations. Cross-sectional data were collected from pregnant and postpartum women who responded to the validated electronic maternal (EMat) health survey. Regardless of receiving advice about GWG, women self-reporting less healthy eating habits in pregnancy than before pregnancy, receiving advice from family/friends about GWG, and lower personal effort to stay within guidelines, had an increased odds of weight gain discordant with recommendations. The objective of the second study was to assess the short-term effect of the SmartMoms Canada application (app) usage on promoting adequate GWG and healthy behaviours. SmartMoms Canada is an app-based intervention designed to help pregnant women adhere to GWG guidelines and improve healthful behaviours. Pregnant women using the SmartMoms Canada app more frequently had a higher moderate-to-vigorous physical activity daily average when compared with women with a lower usage. Together, the EMat and SmartMoms results from this thesis contribute to identifying and mitigating potential factors associated with discordant GWG and healthy behaviours.