Voluntary micronutrient interventions save lives: Evidence from China's free folic acid supplementation policy.

This study assesses the health impacts of a voluntary micronutrient intervention by examining China's Free Folic Acid Supplementation Program (FFASP), a nationwide policy offering free supplements to rural women planning pregnancies since 2008. Using a difference-in-differences design, we estimate that FFASP reduced infant mortality by approximately 2.8%, accounting for 11.7% of the observed narrowing in rural-urban disparities during the intervention period. A cost-benefit analysis indicates that the program averted deaths at $15,552 per life saved, a figure markedly lower than Chinese and global value-of-statistical-life benchmarks. Mortality reductions were most pronounced among female infants and driven by declines in folate deficiency-related complications such as birth defects and low birthweight. Program efficacy was strongest in regions with higher compliance, greater pre-intervention prevalence of neural tube defects, and lower educational attainment. These findings demonstrate that well-targeted voluntary micronutrient interventions can yield significant mortality reductions in resource-limited settings, challenging skepticism toward non-mandatory intervention programs.