Maternal air pollution exposure during the first trimester of pregnancy and markers of inflammation and endothelial dysfunction

Background: Maternal exposure to air pollutants has been associated with pregnancy complications and adverse birth outcomes. Endothelial dysfunction, an imbalance in vascular function, during pregnancy is considered a key element in the development of pre-eclampsia. Environmental exposure to particulate matter (PM) during the first trimester of pregnancy might increase maternal inflammatory status thus affecting fetal growth, possibly leading to preterm delivery. Objectives: The purpose of the study was to evaluate possible effects of PM10 and PM2.5 exposure on fetal growth in healthy pregnant women at the end of the first trimester of pregnancy by investigating the relationship between circulating biomarkers of inflammation (IL-6), early systemic prothrombotic effects (CRP, plasma fibrinogen, PAI-1) and endothelial dysfunction (sICAM-1 and sVCAM-1). Methods: 295 pregnant women were recruited. Individual PM exposure was assigned to each subject by calculating the mean of PM10 and PM2.5 daily values observed during the 30, 60, and 90 days preceding enrolment (long-term) and single lag days back to fourteen days (short-term), and circulating plasma biomarkers were determined. Results: For long-term exposure, we observed an increase in sVCAM-1 and a decrease of PAI-1 levels for each 10 μg/m3 increase in PM10 concentration. Decreases in IL-6 and CRP levels were associated with each 10 μg/m3 PM2.5 increase. For short-term exposure, the levels of sVCAM-1 and PAI-1 were found to be associated with PM10 exposure, whereas fibrinogen levels were associated with PM2.5 exposure. Maternal plasmatic fibrinogen levels were negatively associated with the crown-rump length (p-value = 0.008). Discussion: The present study showed that both long- and short-term exposures to PM are associated with changes in circulating levels of biomarkers in pregnant women reflecting systemic inflammation and endothelial dysfunction/activation. Our findings support the hypothesis that inflammation and endothelial dysfunction might have a central role in modulating the detrimental effects of air pollution exposure during pregnancy.