Maternal Exposure to Particulate Matter during Pregnancy and Adverse Birth Outcomes in the Republic of Korea.

Air pollution has become a global concern due to its association with numerous health effects. We aimed to assess associations between birth outcomes in Korea, such as preterm births and birth weight in term infants, and particulate matter < 10 µm (PM). Records from 1,742,183 single births in 2010⁻2013 were evaluated. Mean PM concentrations during pregnancy were calculated and matched to birth data by registered regions. We analyzed the frequency of birth outcomes between groups using WHO criteria for PM concentrations with effect sizes estimated using multivariate logistic regression. Women exposed to PM > 70 µg/m³ during pregnancy had a higher rate of preterm births than women exposed to PM ≤ 70 µg/m³ (7.4% vs. 4.7%, < 0.001; adjusted odds ratio (aOR) 1.570; 95% confidence interval (CI): 1.487⁻1.656). The rate of low birth weight in term infants increased when women were exposed to PM > 70 µg/m³ (1.9% vs. 1.7%, = 0.278), but this difference was not statistically significant (aOR 1.060, 95% CI: 0.953⁻1.178). In conclusion, PM exposure > 70 µg/m³ was associated with preterm births. Further studies are needed to explore the pathophysiologic mechanisms and guide policy development to prevent future adverse effects on birth outcomes.