Prenatal Exposure to CO and NO2 and Reduced Term Birthweight: A Pilot Study Utilizing Hospital-Based Delivery Data for Environmental Health Research in New Delhi, India

摘要

Background New Delhi is one of the most polluted cities in the world. Pregnant women are exposed to criterion air pollutants that are suspected to reduce birthweight. This study investigates the association of CO and NO2 exposure to birthweight of term neonates born in New Delhi from 2007-2012 (N=10,565) using hospital-based data linked with 10 continuous air quality monitoring station (CAQMS) data reported by the Central Pollution Control Board. Due to the absence of a national birth registry in India, it is important to utilize existing hospital datasets for environmental health assessment studies. Methods 2007-2012 average levels of carbon monoxide (CO), and nitrogen dioxide (NO2) were obtained and linked to delivery data during the same timeframe in an urban hospital in New Delhi. Data from stations within 10 kilometres of maternal residence were assigned to each birth record. Multiple regression analysis was conducted to detect associations between levels of exposure to pollutants and term low birth weight. Results An interquartile range (IQR) increase in ambient pollutant concentrations of CO (580 ppb) and NO2 (26 ppb) during the whole pregnancy was associated with a 19g (95% CI: -36, 2) and 18g (95% CI: -33, -3) decrease in birth weight, respectively, for all births. We assessed pollutant effects by trimester to identify biological exposure window of concern. For CO, the effect is most pronounced during the first trimester. An IQR increase in CO and NO2 was associated with a 26g (95% CI: -50, -3) and 27g (95% CI: -48, -6) decrease in birth weight, respectively, in female births; results were not significant for male births. Conclusions Pregnant women and their neonates are exposed to high levels of CO and NO2 in New Delhi. The medical community can contribute to the policy dialogue by utilizing hospital data for environmental health research. There is a need for a national birth registry to assess early exposures to pollutants and life course impact.