Background and Objective:

The aim of this study was to investigate the association between exposure to ambient air pollution during pregnancy and the risk of spontaneous abortion. This review sought to clarify the impact of air pollution on pregnancy health and to identify research gaps and needs in this field.

Methods: The Web of Science, PubMed, and Scopus databases were systematically searched through September 2025. No time or language restrictions were applied, and the reference lists of relevant studies were also manually screened. All eligible epidemiological studies were included in the review. The quality of the included studies was assessed using the Newcastle–Ottawa Scale (NOS).

Results: Among the 2,034 records identified, 658 duplicate articles were removed. In the initial screening stage, 1,376 articles were assessed, of which 173 were considered eligible for full-text review after title and abstract screening. Ultimately, 15 studies met the inclusion criteria. Overall, the findings of these studies indicated that exposure to air pollutants, including carbon monoxide (CO), sulfur dioxide (SO₂), particulate matter less than 2.5 microns in diameter (PM₂.₅), and ozone (O₃), may be associated with an increased risk of spontaneous abortion.

Conclusion: Considerable inconsistency existed across the findings of the reviewed studies; however, ambient air pollution appears to be a potential risk factor for spontaneous abortion. Further studies are required to confirm these findings.