The power of preterm birth to motivate a cleaner environment.

This commentary reflects on a natural experiment reported by Casey and colleagues that tested the association between living near a coal or oil power plant and preterm birth. They found that retiring power plants resulted in a significant reduction in preterm birth with larger effects observed for late preterm birth and among Non-Hispanic Black mothers and infants. Natural experiments, in particular the Utah Valley steel mill closure, have played a prominent role in the evidence-base for air pollution regulation due to their demonstrated impact on cardio-pulmonary effects in adults. Reproductive health, including infant mortality and preterm birth associated with poor air quality, have generally received less attention. Even small reductions in preterm birth can have a large population health impact, both in terms of preventing mortality in the short-term but also preventing lifelong disability among affected infants.