Attributing preterm births to anthropogenic climate change: a multi-country analysis

Rising temperatures driven by anthropogenic climate change pose a substantial health risk to vulnerable populations, including newborns and pregnant people. Increased exposure to heat extremes can trigger a preterm birth event, which is associated with elevated risks of long-term adverse health, behavioural and cognitive outcomes for the premature individual. However, few studies have assessed how many preterm births are attributable to anthropogenic climate change and none have conducted a multi-country analysis. Our study addresses this gap by estimating the global contribution of human-induced warming to preterm birth incidence. We utilise the new Large Ensemble Single Forcing Model Intercomparison Project (LESFMIP) simulations, used here for the first time in a climate impact attribution study, and test multiple established bias correction methods on the simulations, assessing performance by employing the UNSEEN fidelity test. We apply the latest relationships between preterm birth and temperature, spanning multiple continents, to derive a historical estimate of the number of preterm births caused by anthropogenic climate change. This work provides one of the first multi-country estimates of the burden of preterm birth attributable to anthropogenic climate change, while demonstrating the suitability of LESFMIP simulations for health impact attribution.