Air Pollution During Pregnancy and Neonatal Outcome: A Review

Abstract

There is increasing evidence of the adverse impact of prenatal exposure to air pollution. This is of particular interest, as exposure during pregnancy--a crucial time span of important biological development--may have long-term implications. The aims of this review are to show current epidemiological evidence of known effects of prenatal exposure to air pollution and present possible mechanisms behind this process. Harmful effects of exposure to air pollution during pregnancy have been shown for different birth outcomes: higher infant mortality, lower birth weight, impaired lung development, increased later respiratory morbidity, and early alterations in immune development. Although results on lower birth weight are somewhat controversial, evidence for higher infant mortality is consistent in studies published worldwide. Possible mechanisms include direct toxicity of particles due to particle translocation across tissue barriers or particle penetration across cellular membranes. The induction of specific processes or interaction with immune cells in either the pregnant mother or the fetus may be possible consequences. Indirect effects could be oxidative stress and inflammation with consequent hemodynamic alterations resulting in decreased placental blood flow and reduced transfer of nutrients to the fetus. The early developmental phase of pregnancy is thought to be very important in determining long-term growth and overall health. So-called "tracking" of somatic growth and lung function is believed to have a huge impact on long-term morbidity, especially from a public health perspective. This is particularly important in areas with high levels of outdoor pollution, where it is practically impossible for an individual to avoid exposure. Especially in these areas, good evidence for the association between prenatal exposure to air pollution and infant mortality exists, clearly indicating the need for more stringent measures to reduce exposure to air pollution.

A rapid assessment of the impact of hazard reduction burning around Sydney, May 2016

“…Exposure to PM 2.5 has also been linked to low lung function in 4-year-old children in a birth cohort study in the Netherlands (Eenhuizen et al, 2012), supporting previously published studies that reported effects of PM 2.5 on lung function development, reviewed in Götschi et al (2008). Evidence is increasing for an association of ambient air pollution, including fine particles, with birth outcomes (Parker et al, 2011;Proietti et al, 2013;Ritz & Wilhelm, 2008). A systematic review reported significant associations between exposure to PM 2.5 and birth outcomes, including low birth weight, preterm birth and small for gestational age births (Shah & Balkhair, 2011).…”

Maternal ambient air pollution exposure preconception and during early gestation and offspring congenital orofacial defects

“…A steadily growing body of literature has implicated maternal exposure to air pollution as a potential causal factor in offspring adverse birth outcomes, including infant mortality, low birth-weight, and preterm birth (Proietti et al, 2013; Shah et al, 2011; Stieb et al, 2012). Emerging data also suggests a link between air pollution and congenital anomalies (E.K.…”

Modeling spatial effects of PM2.5 on term low birth weight in Los Angeles County

“…Extensive evidence indicates that prenatal exposure to outdoor air pollution is associated with risk of term low birth weight (Brauer et al, 2008;Fleischer et al, 2014;Ghosh et al, 2013Ghosh et al, , 2012Hyder et al, 2014;Padula et al, 2012;Parker et al, 2011;Ponce, 2005;Proietti et al, 2013;Ritz and Wilhelm, 2008;Shah and Balkhair, 2011;Stieb et al, 2012;Wilhelm et al, 2011;Wu et al, 2011). While TLBW contributes to racial-ethnic and socioeconomic health disparities in the United States, air pollution is thought to be an important place-based factor in the complex geography of and susceptibly to TLBW MorelloFrosch and Shenassa, 2006).…”