Impact of Heat Exposure during Pregnancy in Ethiopian Cities

Impact of Heat Exposure during Pregnancy in Ethiopian Cities

Desalew Meseret Moges^1*, Per-Ola Olsson², Ebba Malmqvist³, Masresha Tessema¹, Eleni Papadopoulou⁴, Kristoffer Mattisson³

¹ Nutrition, Environmental Health and Non-communicable Disease Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia.

² Department of Physical Geography and Ecosystem Science, Lund University, Sweden.

³ Division of Occupational and Environmental Medicine, Lund University, Sweden.

⁴ Global Health Cluster, Norwegian Institute of Public Health, Oslo, Norway.

Abstract
Climate change poses a significant public health threat, particularly for vulnerable groups such as pregnant women and children. Heat stress, when the body struggles to regulate its internal temperature due to high temperatures, presents increased health risks during pregnancy. Exposure to heat stress during pregnancy can result in adverse health outcomes for both the mother and fetus, including preterm birth, low birth weight, stillbirth, and pregnancy complications. However, research on the effects of heat exposure in epidemiological studies remains limited and inconsistent in low-resource countries like Ethiopia. This is mainly due to a lack of comprehensive data and resources. These regions often face limited infrastructure, scarce ground monitors, unreliable data collection systems, and insufficient technological support.

To address these gaps, this heat exposure study, which is part of the EU-funded ENABLE (Enabling Environments for Non-communicable Disease (NCD) risk reduction in Ethiopia) project, with the overarching aim to investigate the impact of urban heat exposure on maternal health outcomes in four Ethiopian cities: Addis Ababa, Jimma, Adama, and Harar. The present study's primary objective is to utilize remote sensing data to evaluate heat exposure.

Land Surface Temperature (LST), which measures the Earth's surface temperature, and the Discomfort Index (DI), which combines air temperature and humidity, will be used to assess heat stress. Data will be collected from satellite sensors (Landsat, MODIS; Moderate Resolution Imaging Spectroradiometer), climate data (ERA5; the fifth generation of the European Centre for Medium-Range Weather Forecasts atmospheric reanalysis of the global climate), and ground measurement from PurpleAir monitors. Heat stress will be assessed using hot days or heat waves when LST and DI exceed the 95th, 97th, or 99th percentiles for two consecutive days. This will involve creating high spatial resolution maps of heat exposure hotspots in Ethiopian cities.

The results from the present study will later be used in the ENABLE project to assess individual exposure to heat stress and effects on pregnancy outcomes. The planned epidemiological studies will include pregnant women recruited within the ENABLE project, with a target enrollment of 5000 participants, following their pregnancies from initiation till birth. Pregnancy outcomes collected from hospitals and public health records will be linked to heat metrics using GPS data from maternal residential addresses. This research provides critical insights into the intersection of climate change and urban heat stress in Ethiopia. The results can potentially inform Ethiopia’s climate-resilient urban planning and maternal health policies.