The evidence on extreme heat and maternal health is robust, growing and increasingly difficult to ignore, and yet the gap between what that evidence recommends and what pregnant women and new mothers are actually able to do in the face of extreme heat remains one of the most persistent challenges in translating climate health research into real-world impact. Understanding why that gap exists, and how to close it, requires the global health community to look beyond the quality of its science and examine the assumptions embedded in how it designs the tools and systems built from that science. 

At the Climes 2026 International Conference on Climate Impacts in a Changing World, co-design emerged as one of the most substantive and consistently revisited themes across sessions. Researchers, practitioners and policymakers working across vastly different climate and social contexts arrived at the same conclusion: climate adaptation strategies and early warning tools are only as effective as the communities they are developed with. Veronika Tirado, postdoctoral researcher at Karolinska Institutet and member of the HIGH Horizons project, attended the conference as a poster presenter, sharing findings from a mixed-methods study on how pregnant women and mothers in Sweden perceive heat risks and experience a heat early warning system app developed to support them. The conversations she encountered there did not simply validate the direction of our work but also sharpened the questions driving it in ways that are directly relevant to the broader challenge of maternal heat health adaptation globally. 

Designing For vs Designing With 

Climate adaptation tools built for vulnerable populations tend to follow a familiar development logic in which researchers identify a risk, build an evidence-based response, package it into a tool or system and deploy it into the communities that need it most. This approach is well-intentioned and often methodologically rigorous, but it carries within it an assumption that researchers are being asked to examine critically: that the people who will use a tool have been adequately considered simply by being named as its intended beneficiaries. 

The distinction between designing for people and designing with them is substantive and  determines whether a tool only works in a controlled research environment or whether it actually changes behaviour, builds trust and delivers measurable health outcomes in the communities it was built to serve. 

Co-design, as it was discussed at Climes 2026, is not a consultation exercise or a user testing session appended to the end of a development process. It is a sustained and structured involvement of community members at every stage of developing a climate adaptation tool: 

• Framing the problem from the community’s perspective 
• Developing the solution in genuine partnership with intended users 
• Refining the tool continuously as it encounters the realities of the people using it 

For maternal health tools in the context of extreme heat, this demands particular attentiveness to the lives of the women they are designed for. Pregnant women and postpartum mothers are already navigating a dense and often contradictory landscape of health information while managing the physiological demands of pregnancy or early motherhood alongside the practical pressures of daily life, work, caregiving and in many contexts, significant structural and socioeconomic barriers to the kind of protective action that clinical guidance recommends. 

This concern that tools designed without adequate community engagement will fail to deliver is also grounded in evidence that HIGH Horizons has generated through its own research across Zimbabwe, South Africa, Greece and Sweden. A recent photovoice study conducted with pregnant and postpartum women in urban townships in South Africa showed clearly that structural and socioeconomic barriers constrain heat adaptation in ways that individual-level interventions cannot address in isolation. Women in those communities were not failing to protect themselves from the heat because they lacked information. They were facing conditions in which the protective actions recommended to them were simply not available or feasible given the realities of their daily lives. The implication is that no digital tool, however technically sophisticated, can bridge that gap without first being designed to understand and respond to these socio-economic barriers. 

This is precisely why HIGH Horizons takes a mixed-methods approach to its research on the MotherHeat Alert app, the heat health early warning system the project has developed for pregnant and postpartum women. The app delivers timely heat alerts alongside actionable, contextually relevant guidance for protecting both mother and baby, drawing on a knowledge base designed specifically for these women and personalised to their own environment and circumstances. Because the effectiveness of such a tool depends as much on how it is experienced and understood as on the clinical evidence underpinning it, user experience and perception data are as central to the research as clinical outcomes. Understanding and clearly answering the following questions is therefore essential: 

• How does a pregnant woman perceive heat risk in her specific context? 
• What information is she aware of, and which information sources does she trust? 
• What barriers does she face in acting on heat health guidance?

The Communication of Uncertainty 

One of the more intricate dimensions of co-design that Climes 2026 brought into refocus was the challenge of communicating uncertainty in risk messaging to pregnant women. Pregnant women are already managing anxiety, competing advice and incomplete information about their health. A heat early warning system that communicates risk in ways that increase anxiety without providing actionable, contextually appropriate guidance is not serving its users but adding to their burden. 

Getting the framing of uncertainty right, in ways that are honest about the limits of what the science can predict while still being genuinely useful to the women receiving the message, is one of the most important and underappreciated design challenges in maternal heat health communication. It is also one that cannot be resolved without sustained engagement with the communities the messaging is designed to reach. 

The broader lesson that Climes 2026 articulated with clarity is that the evidence base on heat and maternal health is growing rapidly, and the window to shape how that evidence is translated into policy and practice is genuinely open. Evidence alone, however, does not change health outcomes. The pathway from research to impact runs through the communities the research was designed to protect, and that pathway has to be built with them. 

Community-based approaches presented at the conference offered concrete examples of what genuinely participatory adaptation looks like in practice, including: 

• Farmers’ agricultural adaptation strategies developed in direct response to community knowledge and need 
• Work on designing out mosquito-borne disease transmission across Scandinavian and sub-Saharan contexts that centred local expertise at every stage 

These examples served as a reminder that the assumptions embedded in technology-led solutions need to be held to a high standard of community engagement and contextual humility, not as a reason to abandon those solutions but as a reason to build them better. 

For HIGH Horizons, the path forward is grounded in the principle of Co-design. The science is clear, the tools are in development, and the communities the project works with have already demonstrated, through the lived experience of women, that the knowledge needed to navigate extreme heat safely exists within the communities that face it most directly. The work now is to build and refine existing systems and tools that are genuinely worthy of that knowledge, designed in real partnership with the women they exist to protect and capable of reaching the places where the heat is most dangerous, and the resources to respond to it are most scarce. HIGH Horizons is an international research consortium funded by the European Union and UKRI, studying how extreme heat affects pregnant and postpartum women, newborns, young children and the health workers who serve them. Learn more at www.high-horizons.eu