Maternal exposure to PM 2.5 blamed

Maternal exposure to fine particulate matter (PM 2.5) is an important risk factor and could be a definitive cause for low birth weight newborns, concluded the country’s first study which provides the quantitative effects estimates for linking rural-urban PM 2.5 and birth weight in India.

This Indian Council for Medical Research-funded study looked at 1,285 pregnant women from urban and rural Tamil Nadu.

The study, ‘Exposure to fine particulate matter and birth weight in a rural-urban, mother-child cohort in Tamil Nadu,’ done between 2010-15 and published recently states that a a 10 ug/m3 increase in PM 2.5 exposure during pregnancy period is associated with a 4 gm decrease in birth weight and 2% increase in prevalence of low birth weight.

Additional burden

“The implication of this is huge in India which has elevated air pollution levels. Low birth weight is an important health issue for India and this only adds additional burden to the already strained newborn health status,” said Kalpana Balakrishnan, the head of the study which was carried out at the Center for Advanced Research on Air Quality, Climate and Health, Sri Ramachandra University, Chennai.

The study also adds important evidence for this association from high exposure settings that experience dual health burdens from ambient and household air pollution.

Speaking about the study, at the Clearing the Air seminar series organised by Centre for Policy Research on Wednesday, she said: “The study results point to the need for considering maternal PM 2.5 exposures alongside other risk factors for low birth weight and other adverse pregnancy outcomes in India. The results also point to the imminent need for strategic air quality actions focused on protecting vulnerable groups such as pregnant women and infants.”

“There is increasing consensus that exposures to ambient and household air pollution may be associated with increased risk of adverse pregnancy outcomes, including intra-uterine growth retardation, low birth weight, and pre-term births.

“The evidence from high exposure settings that are commonly encountered in low and middle income countries has however been sparse,” she added.

Selection

For the study, women in their first trimester of pregnancy from primary healthcare centres and urban health posts were selected and they were followed until birth to collect antenatal care data and birth weight. Mothers also completed detailed questionnaires to provide data on covariates related to household, socio-economic, demographic and maternal health characteristics.