Exposure to Fine Particulate Matter (PM2.5) and Heavy Metals During the Second Trimester of Pregnancy Increases the Risk of Preeclampsia and Eclampsia: An Analysis of National Health Insurance Claims Data from South Korea.

: Air pollutants have been shown to affect hypertensive disorders and placental hypoxia due to vasoconstriction, inflammation, and oxidative stress. The objective of this study was to evaluate whether high levels of maternal exposure to heavy metals during the second trimester of pregnancy are associated with an increased risk of preeclampsia and eclampsia, using national health insurance claim data from South Korea. Data on mothers and their newborns from 2016 to 2020, provided by the National Health Insurance Service, were used ( = 1,274,671). Exposure data for ambient air pollutants (PM2.5, CO, SO, NO, and O) and heavy metals (Pb, Cd, Cr, Cu, Mn, Fe, Ni, and As) during the second trimester of pregnancy were retrieved from the Korea Environment Corporation. Atmospheric condition data based on the mother's registration area were matched. A logistic regression model was adjusted for maternal age, infant sex, season of conception, and household income. In total, 16,920 cases of preeclampsia and 592 cases of eclampsia were identified. In the multivariate model, copper exposure remained significantly associated with an increased risk of preeclampsia (odds ratio: 1.011; 95% confidence interval: 1.001-1.023), and higher ozone exposure during pregnancy was associated with an elevated risk of eclampsia. Increased copper exposure during the second trimester of pregnancy was associated with a high incidence of preeclampsia.