Mental well-being is something that is significantly overlooked around the world, especially in developing countries such as Bangladesh. It is important to look after the mental well-being of pregnant and postpartum women as it may have long-term effects on both mother and child. In this work, we propose a conceptual design and development framework for mobile health (mHealth) apps for providing necessary information and interventions to help deal with the mental well-being of pregnant and postpartum women. We followed this framework to develop a low-fidelity prototype of “GorbhoShongi”, a mHealth app for the people of Bangladesh. It has been developed in English and Bangla to reach a wide range of users. We chose the relevant features after looking at the existing solutions. Also, we decided to add a couple of novel features, a large language model (LLM) chatbot, and daily well-being tips and quotes as it is important to provide a personalized experience and encouragement to the user. We also discussed developing the high-fidelity version using JavaScript frameworks Next.js and Capacitor.js. After creating the high-fidelity prototype, we also plan to test usability and user experience. This work will hopefully encourage more research in the field of mHealth apps for pregnancy-related mental well-being issues.