Relationship between air pollutants and spontaneous abortion in a coal resource valley city: a retrospective cohort study

Abstract

Objective

Pollutants in the atmosphere have been linked to poor pregnancy outcomes in women. However, such investigations are scarce in metropolitan northern China. The major exposure window of air pollution affecting pregnant women is also unknown.

Methods

For the analysis, this retrospective cohort study enrolled 6960 pregnant women recorded at Tongchuan People’s Hospital from January 2018 to December 2019. Pollutant concentration values from the nearest monitoring station to the pregnant women were used to estimate exposure doses for each exposure window. Logistic regression models were created to investigate the connection between pollutants and spontaneous abortion while controlling for confounding factors.

Results

PM_2.5 was a risk factor for spontaneous abortion in T₃ (30–60 days before the first day of the last menstrual period [LMP]), (OR: 1.305, 95% CI: 1.143–1.490) and T₄ (60–90 days before the first day of the LMP),(OR: 1.450, 95% CI: 1.239–1.696) after controlling for covariates. In the same window, PM₁₀ was a risk factor (OR: 1.308, 95% CI: 1.140–1.500), (OR: 1.386, 95% CI: 1.184–1.621). In T₂ (30 days before the first day of the LMP), T₃, and T₄, SO₂ was a risk factor for spontaneous abortion (OR: 1.185, 95% CI: 1.025–1.371), (OR: 1.219, 95% CI: 1.071–1.396), (OR: 1.202, 95% CI: 1.040–1.389). In T₃ and T₄, NO₂ was a risk factor (OR: 1.171, 95% CI: 1.019– 1.346), (OR: 1.443, 95% CI: 1.259–1.655). In T₁ (from the first day of the LMP to the date of abortion), O₃ was found to be a risk factor (OR: 1.366, 95% CI: 1.226–1.521).

Conclusion

Exposure to high levels of air pollutants before and during pregnancy may be a risk factor for spontaneous abortion in pregnant women. This study further illustrates the importance of reducing air pollution emissions.

Keywords:

• NO₂
• O₃
• pm_2.5
• PM₁₀
• SO₂
• spontaneous abortion

Acknowledgments

All methods were carried out in accordance with relevant guidelines and regulations (declaration of helsinki). All experimental protocols were approved by a named institutional and/or licensing committee. Informed consent was obtained from all subjects and/or their legal guardian(s). We thank the National Natural Science Foundation of China (41761100), the Natural Science Basic Research Program of Shaanxi (2018JQ4013).

Ethical approval and consent to participate

This study has passed the biomedical ethics review of Yan’an University School of Medicine, No. 2018051. Informed consent was obtained from all individual participants included in the study.

Authors’ contributions

The authors did not receive support from any organization for the submitted work. Conceptualization: Jinwei He; Methodology: Jinwei He; Formal analysis and investigation: Jinwei He, Jimin Li; Writing - original draft preparation: Jimin Li, Boya Yang, Lang Liu, Jiajia Gu, Meiying Cao; Writing - review and editing: Jimin Li, Jinwei He; Resources: Lili Wu; Supervision: Jinwei He, Lili Wu.

Disclosure statement

The authors declare that they have no known competing fnancial interest or personal relationships that could have appeared to infuence the work reported in this paper.

Data availability statement

All data and information are available.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (number No.41761100); and the Natural Science Basic Research Program of Shaanxi (number 2018JQ4013); and the 2022 National Innovation and Entrepreneurship Training Program for College Students of Yan'an University (number 202210719043).