Air pollution linked to low birthweight babies

Researchers say that air pollution during pregnancy may increase the risk of lower birthweight babies, even at pollution levels below those deemed acceptable in current European Union air-quality directives. This is according to a study published in The Lancet Respiratory Medicine.

A team of European researchers used data from the European Study of Cohorts for Air Pollution Effects (ESCAPE). They analyzed 14 cohort studies from 12 European countries, involving 74,000 women who had singleton babies between 1994 and 2011.

The researchers estimated the air pollution concentrations of nitrogen oxides and particulate matter at the home addresses of the participants, using land-use regression models.

In addition, the team recorded traffic density on the nearest road and total traffic load on all major roads within 100 meters of the participants' homes.

Air pollution 'explains many low birthweight cases'

The findings showed that all air pollutants, particularly fine particulate matter (PM 2.5 - with a diameter of 2.5 micrometers or less), and traffic density reduced the average head circumference of a child at birth and increased the risk of low birthweight at term.

In the study population, average pollution exposure levels ranged from less that 10 micrograms per cubic meter (10µg/m^³) to almost 30µg/m^³.

The researchers estimate that for every increase of 5µg/m^³ in exposure to PM 2.5 throughout pregnancy, the risk of low birthweight at term increases by 18%.

The researchers say:

"We have shown that ambient air pollutants, particularly PM 2.5, and traffic density are associated with increases in risk of low birthweight at term and reductions in birthweight and birth head circumference.

Our findings suggest that in-utero exposure to ambient air pollution in European urban areas could explain a substantial proportion of cases of low birthweight at term."

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