Effects of Ambient Air Pollution on Birth Outcomes: An Overview

Abstract

The ambient air pollution (AAP) is ubiquitarian especially in the western countries and several studies have found correlations with different human pathologies (such as cardiovascular and respiratory diseases). In the last decades the scientific community has focused the studies on the possible effects of AAP on human reproduction, in particular on the pregnant women and birth outcomes. The researches have investigated the possible correlations between AAP and the effects of prenatal exposure and birth outcomes using several parameters such as low birth weight, intrauterine growth restriction, and preterm birth delivery. The authors found that the literature data are in conflict and do not reach univocal results. In fact, not all of the researches show effects and correlations between AAP and birth outcomes and the studies are extremely various and do not use similar methods of analysis. Furthermore the mechanisms of action are unclear. The possible difficulties in this matter should be the lack of an univocal guideline in the studies, the absence of the researches analyzing the particular internal composition of particulate matter (PM), the possible overlap of short and long term exposure. In addition, we have verified the lack of studies of associations between the possible birth defects and ultrafine particulates (UFPs) able to move from pulmonary district to the circulatory system. Birth defects have a potential great impact on individual and public health since they may involve not only immediate but also future impairments of organs and/or metabolic functions. Therefore we suggest further studies that should be performed (a) using same guidelines, (b) analyzing not only the effects of the concentrations of the particulate matter but also of its particular internal composition, and (c) investigating the effects of UFPs on the birth outcomes.