The Relationship between CO Ambient and Low Birth Weight

LBW is the strongest factor related to prenatal, neonatal, postnatal and childhood mortality and morbidity. Air pollution is one of the risk factors that is recently gaining attention. This study was carried out to determine the relationship between the CO ambient and low birth weight in women referring to Tehran hospitals in 2007-2008. In this historical cohort study 225 pregnant women having lived within 5 kilometers of a monitoring station during pregnancy and referring to selected hospitals in Tehran were investigated. An information questionnaire was used for data collection and sampling was done by multistage sampling and convenience method. Women were assigned to low exposure group and high exposure group based on mean exposure to each pollutant during pregnancy. These two groups were matched with respect to confounding factors. SPSS software version 15, T statistics, 2, Man Withnney, and Relative Risk procedures were used for data analysis. The result showed that 31.6% of CO high exposure group and 7.4% of CO low exposure group had Low birth weight baby. The result also showed a significant relationship between exposure to high amount of CO and LBW (p=0.001). Relative Risk calculated with confidence interval (RR=4/67, CI=(1/76-9/43) was found to be 95% and the amount of attributable risk was 66%. Based on these finding, exposure to carbon monoxide pollution can cause LBW. There should be an educational program about the disadvantages of CO pollutant on pregnant women living in densely populated areas of the city. Moreover, practical approaches should be provided to reduce these pollutants.