Perreault Magazine - 47 -
These measures created a unique “natural experiment” for scientists to study the impact of pollution on human health. A prior study by this group, which was also conducted in conjunction with the Beijing Olympics, demonstrated that pollutions levels were linked to physiological changes that increase risk for cardiovascular disease, and that these same air pollution reductions resulted in improvements in several risk factors.
RESEARCHERS LOOKED AT LAST MONTH OF PREGNANCY, A KEY FETAL GROWTH PERIOD
The researchers compiled information from 83,672 term births (37 to 42 weeks gestational age at birth) to mothers in four urban districts in Beijing. They compared birth weights for mothers whose eighth month of pregnancy occurred during the 2008 Olympics/Paralympics with those whose eighth month of pregnancy occurred at the same time of year in the years before (2007) and after (2009) the games when pollution levels were at their normally higher levels. They found that the babies born in 2008 were on average 23 grams larger than those in 2007 and 2009.
Late pregnancy is a particularly important period of fetal growth, as during this time the fetus experiences the greatest amount of physical growth, and the development of the central nervous, cardiovascular, and musculoskeletal systems accelerates. The study suggests that pollution may be interfering with this period of development.
STUDY SHOWS EVEN SHORT-TERM MEASURES LEAD TO BENEFITS
While the biological mechanism by which exposure to pollution causes lower birth weights are not fully understood, the scientists speculate that several factors could play a role, including maternal inflammation, altered placental function, and reduced nutrient delivery to the fetus, which may impede fetal growth.
“While Beijing’s pollution is particularly noteworthy, many of the world’s other cities face similar air quality problems,” said Zhang. “This study shows that pollution controls—even short-term ones—can have positive public health benefits.”
The study was funded by the National Institute of Environmental Health Sciences.