EXPECTANT mothers who are exposed to air pollution from cars are significantly more likely to have smaller babies, a global study has found.
The research led by Newcastle University analysed data from three million births in nine countries, making it the largest of its kind.
It included data from Newcastle and 13 other sites throughout the UK, as well as Europe, Australia, Asia, North America and South America.
Researchers found the higher the level of pollution from vehicles and coal-fired power stations, the greater the rate of low birth weights.
Exposure to air pollution in any stage of pregnancy can stunt the growth of the foetus. Low birth rate is associated with serious health problems, including increased risk of pre-natal death, as well as chronic problems later in life.
Professor Tanja Pless-Mulloli, who led the study at the university, said “As air pollution increases we can see more babies are smaller at birth, which in turn puts them at risk of poor health in later life.
“Microscopic particles, five times smaller than the width of a human hair, are part of the air we breathe every day. We have shown that these are having an effect on pregnant mothers.”
The Newcastle University researchers used records from the city dating back more than 50 years.
Allowing for socio-economic status and occupation, they were able to correlate birth weight with the amount of particles in the outdoor air. Low birth weigh was defined as less than 5lbs 80z or 2,500 grams.
Professor Pless-Mulloli added: “The particles which are effecting pregnant mothers mainly come from burning fossil fuels, and today this is primarily vehicle fumes. Currently in London, we see around 40 units of particulate air pollution, and in Newcastle this is 20 units. Back in the 1960s this figure was at 700 units of air pollution. The study shows that more needs to be done as clean air is really important for the health of newborns.” The international study was led by Dr Tracey J. Woodruff, professor of obstetrics and gynecology and reproductive sciences at the University of California along with Dr Jennifer Parker, of the National Centre for Health Statistics, Centers of Disease and control, US.
Particulate matter found in air pollution is measured in size (microns) and weight (micrograms/ug per cubic meter). In the European Union, England and Wales the limit is 25ug/m3 of particles measuring less than 2.5 microns.
Debates are currently under way to lower this number. In the US and Scotland, regulations require that there be no more than 12ug/m3 of particles. But researchers observed particulate air pollution in Beijing, China of more than 700ug/m3.
“We would like policy-makers to use the result of this study to aid decisions on whether the permitted levels of air pollution should be changed,” said Professor Pless-Mulloli.
Judith Rankin, professor of maternal and paternal epidemiology at Newcastle University added: “This study should not deter future mothers from taking exercise outdoors. The benefits of exercise during pregnancy are well known. These problems need to be addressed by the policy-makers.”