Urban Environmental Exposures, Air Pollution, and Maternal–Offspring Outcomes: A Systematic Review
Background: Urban ambient air pollution and various co-occurring environmental stressors during pregnancy contribute to systemic inflammation, oxidative stress, endothelial dysfunction, and impaired placental perfusion, thereby increasing the risk of adverse maternal and child health outcomes. Therefore, this study aims to systematically synthesize the evidence on the associations between ambient air pollution and co-occurring urban environmental exposures and pregnancy complications affecting maternal and child health, based on the available evidence.Methods: Following PRISMA 2020 guidelines and a defined PECO framework, comprehensive searches were executed on Scopus and ScienceDirect (April 23, 2026; updated May 06, 2026) for literature published between 2022 and 2025. Of 3,547 records identified, 20 articles met the inclusion criteria, comprising 16 empirical observational studies and 4 supporting conceptual articles. Study quality and risk of bias were assessed using the Newcastle-Ottawa Scale and JBI critical appraisal tools.Results: Moderate-certainty evidence indicated that exposure to PM2.5 and NO2 during the preconception and early-to-mid pregnancy periods increased the risks of gestational diabetes mellitus, hypertensive disorders of pregnancy, low birth weight, and preterm birth. Multi-pollutant models consistently provided stronger risk estimates than single-pollutant models. Evidence linking air pollution with gestational hypothyroidism, postpartum mental distress, and offspring neurodevelopmental outcomes remained limited and heterogeneous.Conclusion: Ambient air pollution and related urban environmental exposures are important determinants of maternal and child health. Integrating environmental exposure assessment into antenatal care and strengthening urban emission reduction policies are essential to reduce pregnancy-related health risks.