How the 2008 Beijing Olympics Resulted in Higher Birth Weights

New research has revealed that the decrease in air pollution achieved during the 2008 Beijing Olympics resulted in a rise in birth weights. The study concluded that air pollution causes babies to be born with lower birth weights.

Why did the 2008 Beijing Olympics result in higher birth rates?

Around the time of the 2008 Beijing Olympics, the government took numerous steps to reduce the amount of air pollution in the city. They raised the acceptable levels for permitted vehicle emissions, closed industries and construction down and introduced a mandatory license plate rotation to cut the number of vehicles on the roads.

This intervention by the state created a laboratory-type environment, in which pollution levels could not only be lowered, but their effects also measured.

Beijing is considered to be one of the world’s most polluted cities, but with the government’s efforts, levels of air pollution dropped by 18% to 59% during the 2008 summer Olympics.

Babies who were in the eighth month of pregnancy during the summer of the Olympics were 23g heavier than those born during the same period in 2007 and 2009.

“These findings not only illustrate one of the many significant health consequences of pollution, but also demonstrate that this phenomenon can be reversed,” said associate professor David Rich, a health scientist from the University of Rochester in the US.

“Even a short term reduction in pollution in a community has a very large public health impact. Some of these babies will have fewer complications or diseases later in life. So any time we can improve or increase birth weight we’re protecting not only the babies when they are born, but also in later life.” he said.

Although these results only relate to one city, they could have far reaching implications for the rest of the world.

“A major percentage of the world’s population lives in environments with pollution levels this high. You could name a lot of those cities in China and India. But this shouldn’t be thought of as only a problem in cites with very high air pollution. Even in cities that have lower pollution we see effects on birth weight,” Rich said. You can read more about China’s pollution problems in the following article Are China’s Pollution Problems Too Far-Gone?

During what stage of pregnancy it is important to have clean air?

The study examined the birth weights of mothers who were between one and seven months pregnant during the Beijing Olympics. It found that the babies born to these women were of a similar size.

These mothers had experienced a shorter period of reduced levels of pollution, and then a later exposure to higher levels before giving birth. Rich stated that these results failed to prove there was any positive effects from cleaner air in early pregnancy.

However, it did show that higher levels of air pollution slowed down the fastest phase of foetal development. Typically this is during the eighth month of pregnancy.

Although the actual reason was unknown, Rich said that this was probably due to a nutrient restriction thorough the placenta.

What are the health implications for low weight babies?

The study is important because of the health risks associated with low birth weights. Babies born who are clinically underweight are more at risk of contracting diseases or even death. Low weight at birth has also been linked to decreased lung capacity and asthma.

Jonathan Griggs, a paediatric professor at Queen Mary University of London, agreed that the study confirmed the serious health implications regarding low birth weights. Griggs stressed the impact that the extra weight of 23g could have on an individual child. He warned that for some vulnerable children, this impact would be larger and could potentially force thousands of children in Beijing into a “clinically significant low birth weight” category of under 2.5kg.

“It absolutely does matter because this is showing that dirty air breathed in by mothers can have adverse effects on the developing foetus,” said Griggs.

“I wonder, hypothetically, if you told women that drinking bottled water vs tap water would increase their foetus’ growth by on average 23g - would they dismiss this as irrelevant? It should therefore be the right of all pregnant women to have as clean air as possible,” said Griggs.

For more information about air pollution in China today see our report Air Pollution in China Today- Emissions, APC Equipment and the Effect of the 12th 5-Year Plan.