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

Abstract

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.Citation:Hettfleisch K, Bernardes LS, Carvalho MA, Pastro LD, Vieira SE, Saldiva SR, Saldiva P, Francisco RP. 2017. Short-term exposure to urban air pollution and influences on placental vascularization indexes. Environ Health Perspect 125:753–759; http://dx.doi.org/10.1289/EHP300

Pre‐natal brain development as a target for urban air pollution

“…Impairing placental function and decreasing transplacental oxygen and nutrient transport could be among potential mechanisms by which air pollution could affect foetal brain development during pregnancy. Evidence from birth cohorts suggests that air pollution affects placental function measured by Doppler ultrasound (negative effects on umbilical artery resistance in one study, but not in another during the second and third trimester; and negative associations on flow indices in the first trimester). There is consistent evidence that impaired placental function disrupts foetal neurodevelopment in animals and neurobehavioural development in children.…”

“…In this context, it is important to highlight that foetus has higher exposure than mothers in relation to their body size. Moreover, foetal life exposure results in maternal effects such as plasma viscosity, or systemic low‐grade inflammation, hormonal disruption or epigenetic changes in mother that could impair placenta function which in turn could lead to cardiovascular or neurological disruption …”

“…Moreover, foetal life exposure results in maternal effects such as plasma viscosity, or systemic low-grade inflammation, hormonal disruption or epigenetic changes in mother that could impair placenta function which in turn could lead to cardiovascular or neurological disruption. [40][41][42][43][44][45][46] Impairing placental function and decreasing transplacental oxygen and nutrient transport could be among potential mechanisms by which air pollution could affect foetal brain development during pregnancy. Evidence from birth cohorts suggests that air pollution affects placental function measured by Doppler ultrasound (negative effects on umbilical artery resistance in one study, 41 but not in another 42 during the second and third trimester; and negative associations on flow indices in the first trimester 47 ).…”

Oxidative Stress and Cardiovascular Risk: Obesity, Diabetes, Smoking, and Pollution

“…These include impaired renal blood flow and an increased incidence of renal disease (183,184), exacerbation of metabolic syndrome/diabetes (185–188), changes to the placental circulation (189–191) and epigenetic alterations that may affect the cardiorespiratory health of offspring (192,193). …”

NTP Monograph on the Systematic Review of Traffic-related Air Pollution and Hypertensive Disorders of Pregnancy

“…Although the data are limited, some studies have suggested associations between diminished vascularization indices in the placenta during the first trimester of pregnancy and air pollutants, particularly NO2 (Hettfleisch et al 2017). These indices have been shown to be lower in patients with preeclampsia compared with normotensive pregnancies (Costa et al 2010).…”