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Background Extreme air pollution events, characterised by abnormally high pollutant concentrations, pose a serious threat to human health, particularly among vulnerable populations such as pregnant women. Air pollutants can pass through the placental barrier, impairing fetal development and increasing the risk of premature birth, low birth weight, gestational hypertension and miscarriage. While existing research has examined general air pollution effects on pregnancy, little has been done on the impact of extreme pollution events, which are expected to increase due to climate change. This systematic literature review aims to assess the impact of extreme air pollution events on adverse pregnancy outcomes.Methods A comprehensive literature search was conducted with the last date being on July 1, 2025, using Scopus, Web of Science and PubMed databases. The search was limited to English language and publication dates from 1 January 2015 to 15 June 2025. Both randomised and non-randomised studies were included using the PECOS framework. The Liverpool literature quality assessment tool was used to assess study quality and risk of bias.Results From an initial pool of 5148 records, 26 studies met quality criteria and were included in the final synthesis. From those we found that exposure to wildfire related PM 2.5 during pregnancy was consistently associated with increased risks of preterm birth and low birth weight, Among the included studies, 13 assessed preterm birth and 13 examined birth weight. PM2.5 was the most frequently studied pollutant (23 studies), followed by PM10, SO2, NO2, CO, and O3.Conclusion Despite differences in exposure assessment, study designs and adjustment for confounders, the evidence showed that the overall direction of associations was positive and consistent, suggesting that extreme air pollution events may pose a significant risk to maternal and fetal health.