The impact of extreme heat during pregnancy and childbirth in Johannesburg, South Africa

Heatwaves and Heat Stress are an increasing risk on a global scale with our changing climate. For Southern Africa, it has been demonstrated that the number of heatwaves and heat stress days have increased since the 1980s. Consequently, a greater proportion of people in the region are exposed to extreme heat for longer periods of time. Extreme heat has been shown to have negative effects on maternal health and birth outcomes and is compounded by existing vulnerabilities such as age and lower socio-economic status. Limited previous research in Africa has demonstrated that exposure to extreme heat in the first weeks of pregnancy can cause complications during and after pregnancy such as pre-eclampsia and gestational diabetes. In addition, it has been found that exposure to extreme heat in the region increases the risk of low birth weight, pre-term birth and in some cases stillbirth. In this study, maternal health data from tertiary hospitals in Johannesburg is analysed against local weather station observations for temperature and heat stress. We assess the threshold at which extreme heat has adverse health outcomes during pregnancy and childbirth (intra-partum) and suggest potential interventions to mitigate against this. This work contributes to calls to improve the understanding of the impacts of extreme heat on maternal and child health in Africa. It also supports work to create global maternal and child climate change health indicators, to better inform adaptation and mitigation efforts. This research is part of HIGH horizons which is funded by the European Union’s Horizon Research and Innovation programme under grant agreement no 101057843