London - Women breathing high levels of air pollution during the last month of pregnancy are more likely than unexposed women to give birth to babies with a significantly lower birth weight, according to a study of the effects of air-quality controls introduced during the 2008 Beijing Olympics.
The temporary pollution regulations imposed on the Chinese capital during the games had a measurable and positive impact on the weight of the babies born to mothers who were eight months pregnant at the time, scientists said.
It is the first time that researchers have been able to pinpoint the effect of air pollution levels on a particular development period in the womb, indicating the importance of clean air during the last month of pregnancy when foetal growth is most rapid.
Beijing researchers analysed nearly 84 000 births to mothers living in four urban districts before, during and after the 2008 Olympics, when the government imposed curbs on vehicles and industry to minimise the impact of the city's high levels of pollution on competing athletes.
Scientists found that women who were in the eighth month of their pregnancy during the seven-week period of the Olympics-Paralympics benefited most from the cleaner air. They gave birth to babies who were on average 23 grams heavier than babies born to similar women in 2007 and 2009, when air pollution controls were not as strict.
Researchers said the findings for the eighth month of pregnancy held across different age groups and socio-economic class. “This is the first study to show that when air pollution levels go down during the eighth month of pregnancy, we see an increase in birth weight,” said David Rich, an epidemiologist at the University of Rochester Medical Centre in New York, and lead author of the study published in the journal Environmental Health Perspectives.
The Independent