Air Quality Indicators and Perinatal–Neonatal Outcomes: A Scoping Review

AIM: To map evidence linking maternal exposure to ambient air pollution during pregnancy and around birth when reported, with perinatal outcomes. METHODS: We searched PubMed, Embase and Web of Science for studies evaluating air quality index, fine particulate matter less than 2.5 μm, nitrogen dioxide or ozone in relation to birth weight, preterm birth, stillbirth, neonatal mortality, congenital anomalies or neonatal intensive care unit admission. Two reviewers screened and extracted data independently. We performed a narrative scoping synthesis; pooled odds ratios came from included meta-analyses. RESULTS: Twenty studies were included: 12 cohort studies, 3 case-control studies, 4 systematic reviews with meta-analyses and 1 cross-sectional study. Most assessed in utero exposure by trimester or pregnancy averages; a few assessed exposure around delivery, and none primarily evaluated preconception exposure. Fine particulate matter less than 2.5 μm showed the most consistent associations with lower birth weight and higher preterm birth risk. Nitrogen dioxide was also associated with preterm birth and reduced birth weight. CONCLUSION: Ambient air pollution, especially fine particulate matter less than 2.5 μm and nitrogen dioxide, is associated with adverse perinatal and neonatal outcomes and supports exposure reduction during pregnancy and better research on critical exposure windows.