JMIR Publications

ABSTRACT

Background:

Early Warning Systems (EWS) have the potential to reduce heat-related health risks, yet few are designed specifically for vulnerable populations. Pregnant women and infants, often cared for by postpartum women, are particularly susceptible to heat-related illnesses. The MotherHeat Alert mobile application is a heat EWS specifically developed for pregnant and postpartum women.

Objective:

In this study we aimed to assess the usability and effectiveness of the MotherHeat Alert in the Tshwane District, South Africa.

Objective:

In this study we aimed to assess the usability and effectiveness of the MotherHeat Alert in the Tshwane District, South Africa.

Methods:

This prospective observational evaluation study included a cohort of 201 participants (100 pregnant, 101 postpartum) which were followed over a six-month period. In addition, a questionnaire was administered at three time points; baseline, midline and endline, to collect self-reported information on health, living situation, heat exposure, amongst other parameters. Usability was evaluated in the endline questionnaire through a validated Post-Study System Usability Questionnaire (PSSUQ), using descriptive statistics. Effectiveness was assessed through changes in self-reported heat-protective behaviours between baseline, midline and endline, as well as through endline assessments of heat-health knowledge increase and self-reported behaviour change attributable to the intervention. Generalised estimating equations were used to analyse repeated measures of heat-protective behaviours, while descriptive statistics were used to summarise endline-reported knowledge gains and behaviour change.

Results:

Usability scores indicated high overall usability, with mean PSSUQ scores of 1.76 (SD=0.60) among pregnant women and 1.37 (SD=0.45) among postpartum women. Similar patterns were observed across most PSSUQ subscales, including system usefulness, interface quality and information quality. Most self-reported behaviour change due to alerts received through the app was rated as large to very large by the pregnant women (67.2%) and postpartum women (82.9%). Nevertheless, comparing behaviour change at baseline and endline mainly highlighted a decrease in protective behaviour in both pregnant and postpartum cohorts. Self-reported knowledge increase among pregnant and postpartum women was reported as large to very large following the use of the EWS (79% and 88%, respectively).

Conclusions:

The MotherHeat Alert application demonstrated positive outcomes in usability. Effectiveness showed conflicting results, with positive self-reports on behaviour change and knowledge increase, yet a decrease in protective heat behaviours when comparing baseline and midline with endline results, likely due to seasonality effects. Nevertheless, these findings highlight the potential of tailored EWS to support heat adaptation among pregnant and postpartum populations. Successful implementation and scalability require careful consideration of contextual factors, further assessment of long-term usability and integration into existing health infrastructure. Clinical Trial: The study was registered with the South African National Clinical Trial Registry (DOH-27-032025-5623), as part of the EU and UK-funded High Horizons project.