Nitrogen Dioxide and Low Birth Weight

Research on the effect of nitrogen dioxide (NO2) on low birth weights has revealed a consistent association between maternal exposure to this air pollutant and an increased risk of delivering infants with low birth weights. Numerous studies have examined the relationship between NO2 levels, typically measured as ambient air pollution, and adverse birth outcomes.

Findings indicate that prenatal exposure to NO2, which is primarily emitted by vehicle traffic, power plants, and industrial activities, is linked to a higher likelihood of infants being born with low birth weights. Low birth weight is defined as a birth weight below 2,500 grams (5.5 pounds) and is associated with an increased risk of various health problems in newborns and potential long-term consequences.

The mechanisms through which NO2 affects birth weight are not yet fully understood, but it is believed that the pollutant’s ability to induce inflammation, oxidative stress, and placental dysfunction may play a role. Additionally, pregnant women living in areas with higher NO2 levels may also be exposed to other air pollutants, which can further contribute to adverse birth outcomes.

While the evidence consistently points to a relationship between NO2 exposure and low birth weights, it is essential to note that individual studies may vary in their specific findings and the magnitude of the effect. Nonetheless, these research findings highlight the importance of mitigating air pollution, particularly NO2 emissions, to protect maternal and fetal health and reduce the risk of adverse birth outcomes.


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  2. Siddika N, Balogun HA, Amegah AK, et al. Ambient air pollution exposure and risk of stillbirth: A systematic review and meta-analysis. Environmental Research. 2019;176:108549.
  3. Stieb DM, Chen L, Eshoul M, et al. Ambient air pollution, birth weight and preterm birth: A systematic review and meta-analysis. Environmental Research. 2012;117:100-111.