Association of ambient air pollution with preterm birth risk: A 20 year cohort study in Tehran
Abstract
Introduction: Exposure to ambient air pollution is a critical environmental health risk, with growing evidence linking it to adverse pregnancy outcomes. However, long-term data from Iran remain limited. This study aimed to investigate the association between maternal exposure to major air pollutants and the risk of preterm birth in Tehran.
Materials and methods: This cohort study utilized 20 years of data (2000–2020) from the Tehran Lipid and Glucose Study (TLGS). We analyzed 697 pregnancies, assessing maternal exposure to Particulate Matter (PM₂.₅, PM₁₀), Ozone (O₃), Carbon monoxide (CO), Nitrogen dioxide (NO₂), and Sulfur dioxide (SO₂) from 10 validated monitoring stations. Historical PM₂.₅ concentrations (pre-2010) were reconstructed using archival data. The association between pollutant exposure and preterm birth was analyzed using Generalized Estimating Equation (GEE) models, adjusting for maternal age and Body Mass Index (BMI).
Results: The incidence of preterm birth was 3.7% (26 cases). The adjusted GEE analysis showed a positive and statistically significant association between maternal CO exposure and preterm birth (coefficient = 0.537; 95% CI: 0.158 to 0.917; P = 0.005).
Conclusion: No statistically significant associations were observed for PM₂.₅, PM₁₀, NO₂, SO₂, and O₃ in the adjusted models. Our findings provide evidence suggesting a potential association between maternal exposure to ambient carbon monoxide and preterm birth in this urban population. These findings highlight the potential public health relevance of traffic-related CO exposure for pregnant women in highly polluted urban settings.
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4. Davis EP, Narayan AJ. Pregnancy as a period of risk, adaptation, and resilience for mothers and infants. Development and psychopathology. 2020 Dec;32(5):1625-39.
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6. Decrue F, Townsend R, Miller MR, Newby DE, Reynolds RM. Ambient air pollution and maternal cardiovascular health in pregnancy. Heart. 2023 Nov;109(21):1586-93.
7. Chen H, Oliver BG, Pant A, Olivera A, Poronnik P, Pollock CA, Saad S. Effects of air pollution on human health–Mechanistic evidence suggested by in vitro and in vivo modelling. Environmental research. 2022 Sep 1;212:113378.
8. Pradhan SH, Gibb M, Kramer AT, Sayes CM. Peripheral (lung-to-brain) exposure to diesel particulate matter induces oxidative stress and increased markers for systemic inflammation. Environmental Research. 2023 Aug 15;231:116267.
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11. Nowadly C, Johnson-Arbor K, Boyle A. Severe unintentional first trimester carbon monoxide poisoning: case report. Undersea & Hyperbaric Medicine. 2018 Jul 1;45(4):453.
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13. Craig EA, Lin Y, Ge Y, Wang X, Murphy SK, Harrington DK, Miller RK, Thurston SW, Hopke PK, Barrett ES, O’Connor TG. Associations of gestational exposure to air pollution and polycyclic aromatic hydrocarbons with placental inflammation. Environment & Health (Washington, DC). 2024 Jul 30;2(9):672.
14. Ruano CS, Miralles F, Méhats C, Vaiman D. The impact of oxidative stress of environmental origin on the onset of placental diseases. Antioxidants. 2022 Jan 1;11(1):106.
15. Hu P, Ran SS, Lin QM, Yang Y, Zhang ZL, Guo XL, Gao YG, Zhao JD, Lin HL. Association between ambient ozone exposure during pregnancy and risk of preterm birth in Guangdong Province.
16. Dastoorpoor M, Idani E, Goudarzi G, Khanjani N. Acute effects of air pollution on spontaneous abortion, premature delivery, and stillbirth in Ahvaz, Iran: a time-series study. Environmental science and pollution research. 2018 Feb;25(6):5447-58.
17. Ranjbaran M, Mohammadi R, Yaseri M, Kamari M, Yazdani K. Ambient temperature and air pollution, and the risk of preterm birth in Tehran, Iran: a time series study. The Journal of Maternal-Fetal & Neonatal Medicine. 2022 Feb 16;35(4):726-37.
18. Aghaei M, Yaseri M, Shendi MR, Asbagh FA, Yousefian F, Past V, Mahvi AH. Long-term exposure to air pollution and risk of preterm birth and low birth weight in Tehran, Iran. Journal of Air Pollution and Health. 2021.
19. Norooziyan M, Karami F, Shahdadnejad M, Nikbakht M, Abbasnia M. The association between urban pollutants and preterm birth occurrences: a case study of Mashhad-Iran. Resources and Environmental Economics. 2019 Apr 4;1(2):50-6.
20. Janghorbani M, Piraei E. Association between air pollution and preterm birth among neonates born in Isfahan, Iran. Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences. 2013 Oct;18(10):875.
21. Azizi F. Tehran lipid and glucose study: a national legacy. International Journal of Endocrinology and Metabolism. 2018 Oct 9;16(4 Suppl):e84774.
22. Azizi F, Rahmani M, Emami H, Mirmiran PA, Hajipour R, Madjid M, Ghanbili J, Ghanbarian A, Mehrabi J, Saadat N, Salehi P. Cardiovascular risk factors in an Iranian urban population: Tehran lipid and glucose study (phase 1). Sozial-und präventivmedizin. 2002 Dec;47(6):408-26.
23. Goyal A, Gupta Y, Tandon N. Overt diabetes in pregnancy. Diabetes Therapy. 2022 Apr;13(4):589-600.
24. Yousefian F, Faridi S, Azimi F, Aghaei M, Shamsipour M, Yaghmaeian K, Hassanvand MS. Temporal variations of ambient air pollutants and meteorological influences on their concentrations in Tehran during 2012–2017. Scientific reports. 2020 Jan 15;10(1):292.
25. Fang GC, Chang CN, Wu YS, Fu PP, Chang KF, Yang DG. The characteristic study of TSP, PM2. 5∼ 10 and PM2. 5 in the rural site of central Taiwan. Science of the total environment. 1999 Aug 1;232(3):177-84.
26. Brook JR, Dann TF, Burnett RT. The relationship among TSP, PM10, PM2. 5, and inorganic constituents of atmospheric participate matter at multiple Canadian locations. Journal of the Air & Waste Management Association. 1997 Jan 1;47(1):2-19.
27. Liang KY, Zeger SL. Longitudinal data analysis using generalized linear models. biometrika. 1986 Apr 1:13-22.
28. Eddings W, Marchenko Y. Diagnostics for multiple imputation in Stata. The Stata Journal. 2012 Sep;12(3):353-67.
29. Torbatian S, Hoshyaripour A, Shahbazi H, Hosseini V. Air pollution trends in Tehran and their anthropogenic drivers. Atmospheric Pollution Research. 2020 Mar 1;11(3):429-42.
30. Bleecker ML. Carbon monoxide intoxication. Handbook of clinical neurology. 2015 Jan 1;131:191-203.
31. Tuoni C, Nuzzi G, Scaramuzzo RT, Fiori S, Filippi L. Neonatal hypoxic-ischemic encephalopathy after acute carbon monoxide intoxication during pregnancy. A case report and brief review of the literature. Frontiers in Pediatrics. 2023 Nov 3;11:1264855.
32. Stieb DM, Chen L, Eshoul M, Judek S. Ambient air pollution, birth weight and preterm birth: a systematic review and meta-analysis. Environmental research. 2012 Aug 1;117:100-11.
33. Ming X, Yang Y, Li Y, He Z, Tian X, Cheng J, Zhou W. Association between risk of preterm birth and long-term and short-term exposure to ambient carbon monoxide during pregnancy in chongqing, China: a study from 2016-2020. BMC public health. 2024 May 27;24(1):1411..
34. Partha DB, Yasmin S, Nath H. Preterm births attributable to criteria air pollutant exposure in Bangladesh during 2015–2019. Environmental Pollution. 2025 Mar 1;368:125742.
35. Zhang X, Fan C, Ren Z, Feng H, Zuo S, Hao J, Liao J, Zou Y, Ma L. Maternal PM2. 5 exposure triggers preterm birth: a cross-sectional study in Wuhan, China. Global health research and policy. 2020 May 1;5(1):17.
36. Li XiangYu LX, Huang ShuQiong HS, Jiao AnQi JA, Yang XuHao YX, Yun JunFeng YJ, Wang YuXin WY, Xue XiaoWei XX, Chu YuanYuan CY, Liu FeiFei LF, Liu YiSi LY, Ren Meng RM. Association between ambient fine particulate matter and preterm birth or term low birth weight: an updated systematic review and meta-analysis. 2017: 596-605.
37. Namvar Z, Mohseni-Bandpei A, Shahsavani A, Amini H, Mousavi M, Hopke PK, Shahhosseini E, Khodagholi F, Hashemi SS, Azizi F, Ramezani Tehrani F. Long-term exposure to air pollution and anti-mullerian hormone rate of decline: a population-based cohort study in Tehran, Iran. Environmental Science and Pollution Research. 2023 Aug;30(37):86987-97.
38. Namvar Z, Ramezani Tehrani F, Shahsavani A, Amini H, Khodagholi F, Hashemi SS, Mousavi M, Hopke PK, Shahhosseini E, Azizi F, Mohseni-Bandpei A. Association of ambient air pollution and age at menopause: a population-based cohort study in Tehran, Iran. Air Quality, Atmosphere & Health. 2022 Dec;15(12):2231-8.
2. Ward VC, Lee AC, Hawken S, Otieno NA, Mujuru HA, Chimhini G, Wilson K, Darmstadt GL. Overview of the global and US burden of preterm birth. Clinics in Perinatology. 2024 Jun 1;51(2):301-11.3.
3. Sharifi N, Khazaeian S, Pakzad R, Chehreh H. Investigating the prevalence of preterm birth in Iranian population: a systematic review and meta-analysis. Journal of caring sciences. 2017 Dec 1;6(4):371.
4. Davis EP, Narayan AJ. Pregnancy as a period of risk, adaptation, and resilience for mothers and infants. Development and psychopathology. 2020 Dec;32(5):1625-39.
5. Fussell JC, Jauniaux E, Smith RB, Burton GJ. Ambient air pollution and adverse birth outcomes: a review of underlying mechanisms. BJOG: An International Journal of Obstetrics & Gynaecology. 2024 Apr;131(5):538-50.
6. Decrue F, Townsend R, Miller MR, Newby DE, Reynolds RM. Ambient air pollution and maternal cardiovascular health in pregnancy. Heart. 2023 Nov;109(21):1586-93.
7. Chen H, Oliver BG, Pant A, Olivera A, Poronnik P, Pollock CA, Saad S. Effects of air pollution on human health–Mechanistic evidence suggested by in vitro and in vivo modelling. Environmental research. 2022 Sep 1;212:113378.
8. Pradhan SH, Gibb M, Kramer AT, Sayes CM. Peripheral (lung-to-brain) exposure to diesel particulate matter induces oxidative stress and increased markers for systemic inflammation. Environmental Research. 2023 Aug 15;231:116267.
9. Chen H, Oliver BG, Pant A, Olivera A, Poronnik P, Pollock CA, Saad S. Particulate matter, an intrauterine toxin affecting foetal development and beyond. Antioxidants. 2021 May 6;10(5):732.
10. Bongaerts E, Aengenheister L, Dugershaw BB, Manser P, Roeffaers MB, Ameloot M, Nawrot TS, Bové H, Buerki-Thurnherr T. Label-free detection of uptake, accumulation, and translocation of diesel exhaust particles in ex vivo perfused human placenta. Journal of Nanobiotechnology. 2021 May 17;19(1):144.
11. Nowadly C, Johnson-Arbor K, Boyle A. Severe unintentional first trimester carbon monoxide poisoning: case report. Undersea & Hyperbaric Medicine. 2018 Jul 1;45(4):453.
12. T Tuoni C, Nuzzi G, Scaramuzzo RT, Fiori S, Filippi L. Neonatal hypoxic-ischemic encephalopathy after acute carbon monoxide intoxication during pregnancy. A case report and brief review of the literature. Frontiers in Pediatrics. 2023 Nov 3;11:1264855.
13. Craig EA, Lin Y, Ge Y, Wang X, Murphy SK, Harrington DK, Miller RK, Thurston SW, Hopke PK, Barrett ES, O’Connor TG. Associations of gestational exposure to air pollution and polycyclic aromatic hydrocarbons with placental inflammation. Environment & Health (Washington, DC). 2024 Jul 30;2(9):672.
14. Ruano CS, Miralles F, Méhats C, Vaiman D. The impact of oxidative stress of environmental origin on the onset of placental diseases. Antioxidants. 2022 Jan 1;11(1):106.
15. Hu P, Ran SS, Lin QM, Yang Y, Zhang ZL, Guo XL, Gao YG, Zhao JD, Lin HL. Association between ambient ozone exposure during pregnancy and risk of preterm birth in Guangdong Province.
16. Dastoorpoor M, Idani E, Goudarzi G, Khanjani N. Acute effects of air pollution on spontaneous abortion, premature delivery, and stillbirth in Ahvaz, Iran: a time-series study. Environmental science and pollution research. 2018 Feb;25(6):5447-58.
17. Ranjbaran M, Mohammadi R, Yaseri M, Kamari M, Yazdani K. Ambient temperature and air pollution, and the risk of preterm birth in Tehran, Iran: a time series study. The Journal of Maternal-Fetal & Neonatal Medicine. 2022 Feb 16;35(4):726-37.
18. Aghaei M, Yaseri M, Shendi MR, Asbagh FA, Yousefian F, Past V, Mahvi AH. Long-term exposure to air pollution and risk of preterm birth and low birth weight in Tehran, Iran. Journal of Air Pollution and Health. 2021.
19. Norooziyan M, Karami F, Shahdadnejad M, Nikbakht M, Abbasnia M. The association between urban pollutants and preterm birth occurrences: a case study of Mashhad-Iran. Resources and Environmental Economics. 2019 Apr 4;1(2):50-6.
20. Janghorbani M, Piraei E. Association between air pollution and preterm birth among neonates born in Isfahan, Iran. Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences. 2013 Oct;18(10):875.
21. Azizi F. Tehran lipid and glucose study: a national legacy. International Journal of Endocrinology and Metabolism. 2018 Oct 9;16(4 Suppl):e84774.
22. Azizi F, Rahmani M, Emami H, Mirmiran PA, Hajipour R, Madjid M, Ghanbili J, Ghanbarian A, Mehrabi J, Saadat N, Salehi P. Cardiovascular risk factors in an Iranian urban population: Tehran lipid and glucose study (phase 1). Sozial-und präventivmedizin. 2002 Dec;47(6):408-26.
23. Goyal A, Gupta Y, Tandon N. Overt diabetes in pregnancy. Diabetes Therapy. 2022 Apr;13(4):589-600.
24. Yousefian F, Faridi S, Azimi F, Aghaei M, Shamsipour M, Yaghmaeian K, Hassanvand MS. Temporal variations of ambient air pollutants and meteorological influences on their concentrations in Tehran during 2012–2017. Scientific reports. 2020 Jan 15;10(1):292.
25. Fang GC, Chang CN, Wu YS, Fu PP, Chang KF, Yang DG. The characteristic study of TSP, PM2. 5∼ 10 and PM2. 5 in the rural site of central Taiwan. Science of the total environment. 1999 Aug 1;232(3):177-84.
26. Brook JR, Dann TF, Burnett RT. The relationship among TSP, PM10, PM2. 5, and inorganic constituents of atmospheric participate matter at multiple Canadian locations. Journal of the Air & Waste Management Association. 1997 Jan 1;47(1):2-19.
27. Liang KY, Zeger SL. Longitudinal data analysis using generalized linear models. biometrika. 1986 Apr 1:13-22.
28. Eddings W, Marchenko Y. Diagnostics for multiple imputation in Stata. The Stata Journal. 2012 Sep;12(3):353-67.
29. Torbatian S, Hoshyaripour A, Shahbazi H, Hosseini V. Air pollution trends in Tehran and their anthropogenic drivers. Atmospheric Pollution Research. 2020 Mar 1;11(3):429-42.
30. Bleecker ML. Carbon monoxide intoxication. Handbook of clinical neurology. 2015 Jan 1;131:191-203.
31. Tuoni C, Nuzzi G, Scaramuzzo RT, Fiori S, Filippi L. Neonatal hypoxic-ischemic encephalopathy after acute carbon monoxide intoxication during pregnancy. A case report and brief review of the literature. Frontiers in Pediatrics. 2023 Nov 3;11:1264855.
32. Stieb DM, Chen L, Eshoul M, Judek S. Ambient air pollution, birth weight and preterm birth: a systematic review and meta-analysis. Environmental research. 2012 Aug 1;117:100-11.
33. Ming X, Yang Y, Li Y, He Z, Tian X, Cheng J, Zhou W. Association between risk of preterm birth and long-term and short-term exposure to ambient carbon monoxide during pregnancy in chongqing, China: a study from 2016-2020. BMC public health. 2024 May 27;24(1):1411..
34. Partha DB, Yasmin S, Nath H. Preterm births attributable to criteria air pollutant exposure in Bangladesh during 2015–2019. Environmental Pollution. 2025 Mar 1;368:125742.
35. Zhang X, Fan C, Ren Z, Feng H, Zuo S, Hao J, Liao J, Zou Y, Ma L. Maternal PM2. 5 exposure triggers preterm birth: a cross-sectional study in Wuhan, China. Global health research and policy. 2020 May 1;5(1):17.
36. Li XiangYu LX, Huang ShuQiong HS, Jiao AnQi JA, Yang XuHao YX, Yun JunFeng YJ, Wang YuXin WY, Xue XiaoWei XX, Chu YuanYuan CY, Liu FeiFei LF, Liu YiSi LY, Ren Meng RM. Association between ambient fine particulate matter and preterm birth or term low birth weight: an updated systematic review and meta-analysis. 2017: 596-605.
37. Namvar Z, Mohseni-Bandpei A, Shahsavani A, Amini H, Mousavi M, Hopke PK, Shahhosseini E, Khodagholi F, Hashemi SS, Azizi F, Ramezani Tehrani F. Long-term exposure to air pollution and anti-mullerian hormone rate of decline: a population-based cohort study in Tehran, Iran. Environmental Science and Pollution Research. 2023 Aug;30(37):86987-97.
38. Namvar Z, Ramezani Tehrani F, Shahsavani A, Amini H, Khodagholi F, Hashemi SS, Mousavi M, Hopke PK, Shahhosseini E, Azizi F, Mohseni-Bandpei A. Association of ambient air pollution and age at menopause: a population-based cohort study in Tehran, Iran. Air Quality, Atmosphere & Health. 2022 Dec;15(12):2231-8.
| Files | ||
| Issue | Vol 11 No 3 (2026): Summer 2026 | |
| Section | Original Research | |
| Keywords | ||
| Preterm birth; Air pollution; Carbon monoxide (CO); Cohort study; Maternal exposure | ||
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
How to Cite
1.
Khoddam S, Ramazani Tehrani F, Borgheipour H, Mousavi M, Mohammadi H. Association of ambient air pollution with preterm birth risk: A 20 year cohort study in Tehran. JAPH. 2026;11(3):377-394.
