Pollution and birth weight linked

Pollution levels have been found to affect birth weight in China.

Scientist at the University of Rochester Medical Center used weight data and discovered that during the 2008 Beijing Olympics when air pollution concentrations were reduced, children were recorded to have higher birth weight.

“The results of this study demonstrate a clear association between changes in air pollutant concentrations and birth weight. These findings not only illustrate one of the many significant health consequences of pollution, but also demonstrate that this phenomenon can be reversed,” said research leader Dr David Rich at the University of Rochester Medical Center.

During the 2008 Beijing Olympics and Paralympics, the Chinese government launched strict pollution control to improve the city’s poor air quality.

These measures produced a significant decrease in air contamination for seven weeks – a 60% reduction in sulphur dioxide, a 48% decrease in carbon monoxide, a 43% reduction in nitrogen dioxide, and a reduction in particles smaller than 2.5µm in diameter.

In the study, published in Environmental Health Perspectives, the team used data from 83,672 term births from mothers in four urban districts in Beijing. They collected birth weight data from mothers whose eighth month of pregnancy occurred during the 2008 Olympic Games.

The team then compared the weights of mothers 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 normal levels.

The results showed that the babies born in 2008 were on average 23g larger than those in 2007 and 2009. The scientists believe that exposure to pollution could potentially cause maternal inflammation, altered placental function, and reduced nutrient delivery to the foetus leading to lower birth weights.

“While Beijing’s pollution is particularly noteworthy, many of the world’s other cities face similar air quality problems. This study shows that pollution controls – even short-term ones – can have positive public health benefits,” said research partner Dr Junfeng Zhang.