We evaluate the impact of a nationwide public health intervention on deaths from sudden infant death syndrome (SIDS), using population data from Denmark in a regression discontinuity research design. The information campaign—implemented primarily through a universal nurse home visiting program—reduced infant mortality by 17.2% and saved between 11.6 and 13.5 lives over 10,000 births. The estimated effect sizes are 11–14 times larger among low-birthweight and preterm infants relative to the overall population. Improvement in infant mortality is concentrated among those with low socioeconomic status and with limited access to health information, thereby reducing health inequities at birth.