Air pollution effects in pregnancy

Greater diffusion of industries and vehicular traffic caused a major impairment of air quality especially in urban areas. The adverse impact on respiratory and cardiovascular systems and the association with lung cancer have been highlighted in several reports. Furthermore, recent evidences highlighted air pollution as a risk factor for the development of type 2 diabetes. It is well known that children, elderly, and pregnant women are more vulnerable to the effects of air pollution. Embryos and fetuses are particularly subject to damage from air pollutants given the susceptibility of developing organs. Consistent data from different continents have demonstrated an increased risk of negative gestational outcomes in mothers exposed to air pollution. In particular, air pollutants have been associated with several adverse birth outcomes such as preterm delivery and low birth weight. However, from available data it is not clear whether the effects are due to a specific pollutant or to the interactions of different molecules, and it is still not clear in which trimester the exposure is more harmful to the fetal development. The exact mechanism of maternal air pollution exposure on adverse birth outcomes is still partially unknown, but some authors hypothesized that oxidative stress, inflammation, and hemodynamic changes associated with air pollutants can impair oxygen and nutrient transport to the fetus. Despite an ever-growing volume of studies, scientific literature regarding this topic is still characterized by enormous heterogeneity in designs and settings leading to several inconclusive results. Further research is therefore needed to identify molecules and mechanism through which air pollution can impair gestational outcomes. These data could lead to implementation of prevention politics and help health-care providers to give useful and more detailed information to mothers.