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Women in Beijing, China Delivered Heavier Babies When Air Was Cleaner


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It is reported that pregnant ladies in Beijing during the period of the 2008 Olympics have welcomed their new born babies with more weight because of temporarily reduced air pollution at that time. According to information released in the recent edition of Environmental Health Perspectives, if a woman is exposed to high levels of pollution during the final weeks of her pregnancy, it could greatly affect the growth and development of the fetus.

Based on previous studies, there should be some link between low birth weight and high concentrations of air pollutants experienced during pregnancy. However, is it true that pollution could be decisive factor for such phenomenon? In order to confirm it, a team led by David Rich of University of Rochester and Kaibo Liu from Beijing Capital Medical University resorted to a natural experiment: In the months prior to the 2008 Olympics and Paralympics, the Chinese government took some serious measures for better improvement of poor air quality in Beijing, for example, strictly limiting auto use, temporally shutting down factories, stopping construction projects as well as other attempts at cloud seeding. As a result of a six-to-seven-week period campaign, it was boasted that in Beijing, the decrease of sulfur dioxide concentrations, carbon monoxide, and nitrogen dioxide had been made by 60 percent, 48 percent and 43 percent respectively. At the same time, there were fewer particles smaller than 2.5 microns in diameter in the air over the city.

With the collected data on 83,672 full-term births by women residing in Beijing’s four urban districts, the team gave special attention to how many months pregnant each mother-to-be was from August 8 through September 24, 2008. Afterwards, they made the comparison between these Olympic babies and newborns from the same period in 2007 and 2009 in regard to their birth weights.

In the study, scientists discovered that women who were pregnant during the games did give birth to higher-birth-weight, babies in comparison with those who were pregnant before and after the games, especially for women who were eight months pregnant during the Olympics, they gave birth to children with twenty-three grams heavier on average. However, the team did not find the major link between pollution and birth weight for months one through seven.

As Rich said, their study had clearly illustrated an association between changes in air pollutant concentrations and birth weight. At the later stage of the pregnancy, the fetus would undergo the most part of physical growth as well as the development of the central nervous, cardiovascular, musculoskeletal systems in the accelerating way. According to Rich’s team, their findings not only showed one of the many obvious health consequences of pollution, but also revealed  that something could be done to reverse such phenomenon can be reversed. At present, scientists are making efforts to identify the exact way in which pollution could lead to lower birth weights.

Source: University of Rochester

Journal reference: Rich, David Q., et al. “Differences in Birth Weight Associated with the 2008 Beijing Olympic Air Pollution Reduction: Results from a Natural Experiment.”Environmental health perspectives (2015).