The Impact of Lead Water Pollution on Birth Outcomes: A Natural Experiment in Scotland

Abstract

We explore whether maternal lead exposure affects birthweights and child mortality in a setting where average blood lead levels were extremely high. We analyse two drinking water interventions in Scotland that reduced lead levels in Glasgow and Edinburgh from 1978 onwards. Using a staggered difference-in-differences design we examine administrative data of over 650,000 births between 1975 and 2000. We do not find consistent evidence of any effect leading to an increase in birthweights or a reduction in under-5 mortality. We estimate minimal detectable effects and can rule out even very low changes in birthweight, but we cannot rule out 1–3 deaths prevented per thousand due to the treatments. As our focus is on short-run outcomes around the time of birth, these findings do not rule out the possibility of longer-term impacts from early-life lead exposure. We also suggest our findings indicate future research should further explore the mediating pathways between lead and health outcomes.