This thesis walks the reader through the research and design process of ‘HelloPreggo!’, a tool developed for pregnant teenagers to guide them towards a healthier nutritional lifestyle during pregnancy. To start off, both literature and empirical research have been conducted on teenagers who are pregnant in the Netherlands in order to understand (1) who we are talking about, (2) what their current situation is and (3) what needs and values can be identified within this target group. Literature was found on the professional perspective of teenage pregnancies. Subsequently, three professionals in the field have been interviewed among which an author of a paper. This research identified many contextual factors that the target group has to deal with. These context factors leave them clueless & indecisive and affect their self-esteem & self-efficacy. Their resilience, however, is strong and they are willing to do what is best for their unborn child. A context mapping research was done to gain deeply rooted information from the target group itself. Sensitising booklets gave clear insights into their daily life and their behaviour towards food. Subsequently, generative sessions were held that provided insights in their underlying values and needs; e.g. the status of being a mother, not to be perceived as less, a need for peers and daily activities. In addition, literature research was conducted on food behaviour and behavioural change. Based on the findings in the conducted researches, a list with twenty design guidelines was established together with the following design goal: ‘To create a set of experiences that engages young mothers-to-be to mature towards a healthy nutritional lifestyle during pregnancy’. This design goal was enhanced with a clear interaction vision and personas that visually characterise the target group. The design process started off with a brainstorm session after which a design direction was chosen. This evolved into the initial concept of a gamified idea of a ‘cookbook learning calendar’ consisting out of challenges. The goal of the game is simple: to complete all challenges and to get a hold of all items. Simultaneously, the user gains knowledge and skills about making healthy food choices. During each challenge, players gain knowledge about a nutritionally related subject and are provided with physical items to apply the newly gained knowledge to. The catch in this game is that the user needs the other players to continue to the next challenge. Aspects of this concept were further elaborated through several interventions; looking at the overall concept, its interactions and the design & content of all components. Hence, “HelloPreggo!” has been created.An interactive prototype was used to evaluate the concept. For this evaluation, a usage scenario movie has been created. This showcased the intended interactions to which the target group has responded. Subsequently, the different components of the concept have been evaluated. Attention has been given towards the implementation of the concept. The business model canvas was used to display the complete network behind “HelloPreggo!”, looking at two different cases; as a stand-alone organisation and complementary to an existing organisation. The closing chapter of this thesis finalises this report with a conclusion, limitations and recommendations of the concept for future research and development.