OUTDOOR POLLUTION AND LOW BIRTH WEIGHT

Air pollution, as an environmental factor affects the health status and growth of the fetus, considering that the air pollutants have dramaticaly increased in Tehran, reviewing the effects of them on the health situation of infants, which are very vulnerable seems to be of great importance. Hence, a retrospective cohort study was conducted on 1000 randomly selected newborns with gestational age of 28-42 weeks. Infants were assigned in two groups and compared based on their mother's areas of residency, during the third trimester of pregnancy. Findings showed that those mothers, who were the inhabitants of areas, where the level of particulate matters under 10 microns (PM10) and carbon monoxide (CO), reported to be in reasonable level, consequently delivered babies with higher weight in comparison with those lived in areas in which two mentioned pollutants had a higher density. There were significant relationships between maternal exposure to (CO) and low birth weight (P=0.003) and also between maternal exposure to (PM10) and low birth weight (P=0.01). Moreover the relationships between birth weight and concentration of some gasses such as CO, SO2, NO2 and O3 were significantly meaningful and (P) values were respectively (0.011), (0.05), (0.009) and (0.03). Due to the fact that upon increase in the level of air pollutants such as CO, SO2 and NO2 low birth weight is to be anticipated. So mothers who work in polluted areas during their pregnancy are prone to this outcomes. Thus, a similar study is recommended to be conducted focusing on the birth weight of infants of mothers who work during pregnancy. Also responsible authorities should device some plans to diminish the level of air pollution.