Climate change and the mortality of the unborn

Abstract

Although previous studies have examined the association between temperature exposure and pregnancy losses (mainly focusing on the risk of stillbirth), causal estimates are still missing. The literature also lacks projections on the impacts of climate change. Using Hungarian administrative data spanning 1984 to 2018, this paper estimates the effect of temperature on the weekly spontaneous pregnancy loss rate. We show that, compared to a mild temperature, heat causes a substantial increase in the risk of pregnancy loss, whereas cold temperatures slightly decrease it. These impacts are not due to near-term displacement of some pregnancy losses but represent changes in the pregnancy outcomes. Combining the estimated effects with outputs of thirty climate models implies that climate change will increase the spontaneous pregnancy loss rate in the 21st century. The risk of pregnancy loss will be especially elevated during summer.