Exposure to wildfires during pregnancy has negative effects on infant health, according to a study recently published by the Centre for Demographic Studies (CED) at the UAB in the journal Perspectives Demogràfiques. Based on 3.4 million births in Spain between 2008 and 2021, the research identifies two mechanisms: stress and air pollution caused by fine particulate matter (PM2.5) carried by smoke. One effect is a 10% increase in the likelihood of low birth weight. Another effect is an increase in preterm births.
The reduction in birth weight is roughly equivalent to the impact of one week of smoking during pregnancy.
The study Wildfires before birth: How stress and smoke are affecting newborn health in Spain uses data on approximately 3.4 million births registered in Spain between 2008 and 2021, provided by the Spanish National Statistics Institute (INE). The data include all births registered in municipalities with more than 10,000 inhabitants, representing around 85% of total births.
To measure exposure to wildfires, researchers considered the occurrence of at least one large wildfire—defined as one with a burned area exceeding 500 hectares (1,236 acres)—in the mother's municipality of residence during pregnancy, based on data from the European Forest Fire Information System (EFFIS). This proximity measure, based on satellite observations of the burned area, aims to capture not only exposure to air pollution but also the stress, displacement and disruptions to daily life that characterize these events.
