Short-Term Exposure to Urban Air Pollution and Influences on Placental Vascularization Indexes.

BACKGROUND: It has been widely demonstrated that air pollution can affect human health and that certain pollutant gases lead to adverse obstetric outcomes, such as preeclampsia and fetal growth restriction. OBJECTIVES: We evaluated the influence of individual maternal exposure to air pollution on placental volume and vascularization evaluated in the first trimester of pregnancy. METHODS: This was a cross-sectional study on low-risk pregnant women living in São Paulo, Brazil. The women carried passive personal NO2 and O3 monitors in the week preceding evaluation. We employed the virtual organ computer-aided analysis (VOCAL) technique using three-dimensional power Doppler ultrasound to evaluate placental volume and placental vascular indexes [vascularization index (VI), flow index (FI), and vascularization flow index (VFI)]. We analyzed the influence of pollutant levels on log-transformed placental vascularization and volume using multiple regression models. RESULTS: We evaluated 229 patients. Increased NO2 levels had a significant negative association with log of VI (p = 0.020 and beta = -0.153) and VFI (p = 0.024 and beta = -0.151). NO2 and O3 had no influence on the log of placental volume or FI. CONCLUSIONS: NO2, an estimator of primary air pollutants, was significantly associated with diminished VI and VFI in the first trimester of pregnancy.