Fetal growth and maternal exposure to particulate matter during pregnancy

Prior studies reported an association between ambient air concentrations of total suspended particles and SO2 during pregnancy and adverse pregnancy o utcomes. We examined the possible impact of particulate matter up to 10 mu m (PM10) and up to 2.5 mu m (PM2.5) in size on intrauterine growth retardat ion (IUGR) risk in a highly polluted area of Northern Bohemia (Teplice Dist rict). The study group includes all singleton full-term births of European origin over a 2-year period in the Teplice District. Information on reprodu ctive history, health, and lifestyle was obtained from maternal questionnai res. The mean concentrations of pollutants for each month of gestation were calculated using continuous monitoring data. Three intervals (low, medium, and high) were constructed for each pollutant (tertiles). Odds ratios (ORs ) for IUGR for PM10 and PM2.5 levels were generated using logistic regressi on for each month of gestation after adjustment for potential confounding f actors. Adjusted ORs for IUGR related to ambient PM10 levels in the first g estational month increased along the concentration intervals: medium 1.62 [ 95% confidence interval (CI), 1.07-2.46], high 2.64 (CI, 1.48-4.71). ORs fo r PM2.5 were 1.26 (CI, 0.81-1.95) and 2.11 (CI, 1.20-3.70), respectively. N o other associations of IUGR risk with particulate matter were found. Influ ence of particles or other associated air pollutants on fetal growth in ear ly gestation is one of several possible explanations of these results. Timi ng of this effect is compatible with a current hypothesis of IUGR pathogene sis. Seasonal factors, one of the other possible explanations, is less prob able. More investigation is required to examine these findings and alternat ive explanations.