Washington: Pregnant women who live in areas with high air pollution are significantly more likely to bear children of low birth weight, according to the largest international study of its kind.
Mothers who are exposed to particulate air pollution of the type emitted by vehicles, urban heating and coal power plants risk having babies of low birth weight, according to the study.
The study analysed data collected from more than three million births in nine nations at 14 sites in North America, South America, Europe, Asia and Australia.
The study was led by co-principal investigator Tracey J Woodruff, professor of obstetrics and gynecology and reproductive sciences at UC San Francisco along with Jennifer Parker, of the National Center for Health Statistics, Centers for Disease Control and Prevention.
The researchers found that at sites worldwide, the higher the pollution rate, the greater the rate of low birth weight.
Low birth weight, a weight below 2500 grams, is associated with serious health consequences, including increased risk of postnatal morbidity and mortality and chronic health problems in later life, noted lead author Payam Dadvand, of the Centre for Research in Environmental Epidemiology (CREAL) in Barcelona, Spain.
In the study, published in the journal Environmental Health Perspectives, the team assessed data collected from research centres in the International Collaboration on Air Pollution and Pregnancy Outcomes, an international research collaborative established in 2007 to study the effects of pollution on pregnancy outcomes.
Most of the data assessed was collected during the mid-1990s to the late 2000s, and in some cases, earlier.
"What`s significant is that these are air pollution levels to which practically everyone in the world is commonly exposed. These microscopic particles, which are smaller than the width of a human hair, are in the air that we all breathe," said Woodruff in a statement.
Woodruff noted that nations with tighter regulations on particulate air pollution have lower levels of these air pollutants.
"In the United States, we have shown over the last several decades that the benefits to health and wellbeing from reducing air pollution are far greater than the costs. This is a lesson that all nations can learn from," Woodruff said.
Study co-author Mark Nieuwenhuijsen observed that particulate air pollution in Beijing, China has recently been measured higher than 700 microgrammes per cubic meter.
"From the perspective of world health, levels like this are obviously completely unsustainable," he said.
Whether these pregnancy exposures can have effects later in life, currently is under investigation through an epidemiological follow-up of some of the children included in these studies.