The air pollution is a public health problem. The pregnancy period is critical because mother’s exposure to air pollutants could affect the fetal development of humans and animals.

Studies in animals and humans had demonstrated the association between the mother’s exposure to air pollutants, neonatal mortality and birth defects [1-4]. Veras et al. [3] demonstrated an increase in transplacental diffusion of substances in female mouse which were exposed to air pollution at ambient level during the pre-pregnancy and pregnancy periods. In 2009 [4], the same researchers showed that females which inhaled PM (particulate matter) at ambient level presented a decrease in the number of cicles, of folicules and embryo implantation as well as lower weight of puppies. Reliene et al. [5] showed an increase in frequency of mutations in DNA (desoxiribonucleic acid) of puppies whose mothers were exposed to PM.

In studies with women, Lacasãna et al. [6] revealed an association between the increment of 10 μg/m³ in concentration of PM₁₀ and 22% in the deaths of neonates by respiratory diseases. The maternal exposure to O₃ in the second and to CO in third month of pregnancy caused a loss in weight of babies [7-10]. Moreover, the pregnant women who inhaled NO₂ during gestational period present an increase of 25% premature delivery [11]. The mechanism that was suggested to clarify the association between CO and the low weight of neonates would be the competition between this gas and O₂ for the sites in hemoglobin, which would decrease the transport of O₂ to the tissues and harm the fetal development. In terms of the association between O₃ and the decrease in neonate weight, animal studies suggested that this effect would be modulated by maternal inflammatory process. The prematurity could be explained through oxidation of proteins and lipids by NO₂ and the decrease of antioxidant protection of fetus and mother. Experimental studies demonstrated that inhalation of NO₂ during gestational period induced the oxidation of lipids, which are components of placenta, and increased the lethality in post-implatantion period of embryo [12]. Gilboa et al. [13] showed the existence of a positive association between the exposure to CO and the Fallot Tetrology (odds ratio: 2,04); between PM₁₀ and atrial septus defects (odds ratio: 2,27) and between SO₂ and ventricular septus defects (odds ratio: 2,16). Ritz et al. [14] found CO and O₃ inhaled during the second month of pregnancy, which is a critical period for heart development, caused congenital cardiac malformation.

Considering the studies which were presented in this editorial, the mechanisms that are involved in injuries caused to air pollution in pre and post-natal periods are not well known. Therefore, there is a necessity to study more and to increase our knowledge about this subject to determine the effects of pollutant inhalation during the gestational period in adult age. Moreover, these kinds of studies are important to create public health policies to decrease the emission of pollutants in atmosphere.