A week ago on 8 March, the world commemorated International Women’s Day to recognise the participation of women and acknowledge their achievements. I find this to be a good opportunity to raise awareness about how the sacred experiences of pregnancy and childbirth might be negatively influenced by air pollution, in hopes that more can be done to cultivate a safer environment for pregnant women.
Lamichhane et al. (2021) highlight a positive association between air pollution and the stress levels of pregnant women. In particular, they find that exposure to PM2.5, PM10, and ozone induce higher levels of perceived stress among pregnant women. Interestingly, the effects of air pollution appear to vary based on seasonality, with spring seeing the greatest levels of stress, perhaps due to the fact that Seoul (study area) is most polluted during spring.
Figure 1. Differences in PSS (Perceived Stress Scale) scores due to increase in air pollution, by season (Lamichhane et al., 2021)
Meanwhile, Lin et al. (2017) used the Global Severity Index (GSI) as a measure of maternal emotional stress and discovered similarly positive associations between increased air pollution and stress levels among pregnant women. Though the authors conceded that the exact mechanisms through which air pollution induces pregnancy stress “remain unknown”, “oxidative stress” (sounds familiar?) once again surfaces as a possible factor.’
Figure 2. Increased risks of high maternal emotional stress (measured by Global Severity Index (GSI) scores) due to increased concentrations of SO2, NO2, and PM10. (Lin et al., 2017)
Research by Veras et al. (2022) has shown that oxidative stress (again?) is one of several biological manifestations of exposure to particulate matter during pregnancy that heightens the risk of negative birth outcomes. Building upon this fundamental understanding, other studies have demonstrated how an unborn child’s fate may be adversely affected by their mothers’ exposure to air pollution.
For instance, Liu et al. (2022) found that exposure to indoor / household air pollution raises the risk of preterm birth, in which a baby is delivered after less than 37 weeks of gestation. This is highly shocking, given that most pregnant women tend to restrict their activities to indoor spaces (Sun et al., 2022) which are typically deemed to be “safer”.
To make matters worse, the outdoors do not provide a safe respite for pregnant women either, as every 5 μg/m3 increase in PM2.5 concentration makes preterm birth 3% more likely to occur, which also then partly translates to the likelier occurrence of low body weight among newborns. (Mitku et al., 2023). Figure 3 provides a visualisation of the possible extent to which air pollution influences preterm birth rates. As seen, preterm birth rates attributed to air pollution exceed 40% in some of the most polluted parts of the world like China and India.
Figure 3. Percentage of total preterm births which were associated with ambient PM2.5 in 2010 (Darby, 2017)
Finally, I wish to conclude by sharing Proietti et al. (2013)’s grave reminder that prenatal exposure to air pollution can also culminate in far more serious consequences, including a compromised immune system, impaired lung development, respiratory issues, and even infant mortality. Given what has been discussed in this entry, there is an absolutely pressing need to redress air pollution. The arduous period of pregnancy should not be made any tougher for women. Instead, a stress-free environment with clean air will go a long way in helping new mothers stay healthy while ensuring the proper growth and development of many generations of newborns to come.
P.S: My classmate Serene, who is blogging about the relationship between gender and environmental pollution, also posted an entry in honor of International Women’s Day. Check out her blog here!
Until the next entry, breathe safe and be safe!
References
Darby, M. (2017, February 16). Air pollution linked to 2.7 million premature births a year. Climate Home News. Retrieved March 14, 2023, from https://www.climatechangenews.com/2017/02/16/air-pollution-linked-to-2-7-million-premature-births/
Lamichhane, D. K., Jung, D.-Y., Shin, Y.-J., Lee, K.-S., Lee, S.-Y., Ahn, K., Kim, K. W., Shin, Y. H., Suh, D. I., Hong, S.-J., & Kim, H.-C. (2021). Association between ambient air pollution and perceived stress in pregnant women. Scientific Reports, 11(1). https://doi.org/10.1038/s41598-021-02845-4
Lin, Y., Zhou, L., Xu, J., Luo, Z., Kan, H., Zhang, J., Yan, C., & Zhang, J. (2017). The impacts of air pollution on maternal stress during pregnancy. Scientific Reports, 7(1). https://doi.org/10.1038/srep40956
Liu, X.-C., Strodl, E., Huang, L.-H., Hu, B.-J., & Chen, W.-Q. (2022). Effect of prenatal exposure to household air pollution from multiple sources on risk of preterm birth. Atmosphere, 13(12), 2022. https://doi.org/10.3390/atmos13122022
Mitku, A. A., Zewotir, T., North, D., Jeena, P., Asharam, K., Muttoo, S., Tularam, H., & Naidoo, R. N. (2023). Impact of ambient air pollution exposure during pregnancy on adverse birth outcomes: Generalized Structural Equation Modeling Approach. BMC Public Health, 23(1). https://doi.org/10.1186/s12889-022-14971-3
Proietti, E., Röösli, M., Frey, U., & Latzin, P. (2013). Air pollution during pregnancy and neonatal outcome: A Review. Journal of Aerosol Medicine and Pulmonary Drug Delivery, 26(1), 9–23. https://doi.org/10.1089/jamp.2011.0932
Sun, J., Wang, J., Yang, J., Shi, X., Li, S., Cheng, J., Chen, S., Sun, K., & Wu, Y. (2022). Association between maternal exposure to indoor air pollution and offspring congenital heart disease: A case–control study in East China. BMC Public Health, 22(1). https://doi.org/10.1186/s12889-022-13174-0
Veras, M., Waked, D., & Saldiva, P. (2022). Safe in the womb? effects of air pollution to the unborn child and neonates. Jornal De Pediatria, 98. https://doi.org/10.1016/j.jped.2021.09.004