Spirometric evaluation of pregnant women exposed to air pollution in the Metropolitan Region of São Paulo

Introduction: The aim of this study was to evaluate the influence of air pollution exposure on the spirometry parameters in pregnants. Methods: The inclusion criteria: singleton pregnancy, first spirometry (Koko) performed at first trimester of pregnancy, no preexisting maternal diseases and personal passive samplers (PPS) suitable for analysis. The exclusion criteria: change of address, abortion and inadequate spirometry testing. Exposure to pollutants was assessed in first (T1) and third trimester (T3) by the PPS (NO2 and O3 levels) and by data from the Environmental Company of São Paulo State. Due to the small variation in the exposure to pollution, the first (Q1) and fourth quarter (Q4) were compared for each pollutant in T1 and T3 through non-parametrical analysis for repeated measurements. Results: In relation to NO2, pregnants in Q1 had increase in predicted FEF25-75% (forced expiratory values of 25 to 75% of the procedure) from T1 to T3 (p = 0.042) and absolute FEV1/FVC (forced expiratory volume during the first second of the procedure and forced vital capacity ratio) (p = 0,036). In T3, FVC values were statistically higher in Q4 than in Q1 for absolute (p = 0.024) and predicted (p= 0.004) values. In relation to O3, patients in Q4 had a statistically higher FEV1 values in T1 than in T3 (p < 0.001). In relation to PM10, the absolute FVC (p = 0.040) and FEV1 (p = 0.035) were statistically lower in Q4 compared with Q1. Peak expiratory flow (PEF) in T1 of pregnants in Q4 were lower than for in Q1 for absolute (p = 0.006) and predicted (p = 0.041) values. In T3, patients in Q4 displayed statistically lower absolute FEV1/FVC values than the patients in Q1 (p = 0.029). Discussion: We conclude that the exposure to NO2 and O3 was associated with the increase in spirometry, indicating a possible lung function defense or compensatory mechanism. The PM10 was associated with the reduction of spirometry during pregnancy, indicating the harmful effects of that pollutant.