Pregnant women had best make sure they are breathing clean air. A worldwide study has shown that pregnant mothers exposed to air pollution emitted by vehicles and coal power plants, are significantly more likely to have smaller babies. Low birth weight is associated with serious health consequences, including increased risk of prenatal death and chronic health problems in later life.
The study, the largest of its kind, analysed data from more than three million births in nine countries in Europe, North America, South America, Asia and Australia. Published recently in Environmental Health Perspectives, the research establishes that the higher the level of pollution, the greater is the rate of low birth weight. Dr Sundeep Salvi, director of Pune-based Chest Research Foundation, said, “Air pollutants that pregnant mothers inhale directly enter the developing foetus through the umbilical cord blood. This was shown several years ago in a study from New York.”
A total of 287 types of pollutants were identified in the umbilical cord blood that was collected soon after the baby’s birth. There are now several studies that have demonstrated the harmful effects of these pollutants on their growth and health. These babies are not only smaller in size and weight, but also have the risk of developing respiratory and metabolic and cardiovascular diseases when they grow.
Defining low birth weight as being less than 2,500 grams, Salvi said, “It has been identified as a significant risk factor for developing chronic obstructive pulmonary disease (COPD) and asthma when the infants become adults.”
Babies born to mothers living in areas close to high motor vehicular air pollution — less than 50 metres away from the main road — have a greater risk of developing asthma and allergic diseases as compared to babies born to mothers living further away. The environment in which the pregnant mother lives and the quality of air she inhales, determines not only the immediate health of the baby, but also subsequent adult health.
Prof Tanja Pless-Mulloli, who led the UK study at Newcastle University, said, “As air pollution increases, we can see that more babies are smaller at birth, which in turn puts them at risk of poor health later in life. Microscopic particles, five times smaller than the width of a human hair, are part of the air we breathe every day. What we have shown definitively is that these levels are already having an effect on pregnant mothers.”
Researchers said though there was an increasing number of studies indicating the findings of this research, the evidence had so far been insufficient to infer a causal association.
At the research orientation workshop on air quality and weather monitoring system (SAFAR-Pune) , a group of science teachers, doctors, professors and health experts discussed the health impacts of the deteriorating air quality.Dr Sundeep Salvi, Director of Chest Research Foundation, said that a study in Pune showed that people travelling in buses are less affected by pollution than the ones travelling in autorickshaws and on two wheelers. This is because pollution from the diesel-based buses affects the people inside it less than the people outside the bus who are directly exposed to the diesel exhaust. Dr Gufran Beig, programme director of SAFAR, said that the project was not only important from the human health point of view but also revealed an impact on the agricultural crop yield.