Impact of indoor air pollution on maternal cardio-respiratory health and childbirth outcomes: systematic review.

Indoor air pollution (IAP) remains a significant contributor to poor maternal and neonatal health, particularly in low- and middle-income countries (LMICs) where biomass fuel use is prevalent. This systematic review aimed to synthesise available evidence on the impact of IAP on maternal cardio-respiratory health and childbirth outcomes. A comprehensive literature search was conducted using PubMed, Scopus, Web of Science, and Google Scholar for studies published between January 2014 and February 2025. Eligible studies included observational or interventional research that reported on exposures to indoor air pollutants (e.g. biomass smoke, particulate matter, and carbon monoxide) and outcomes, such as hypertension, respiratory illness, preterm birth, or low birth weight. Forty studies met the inclusion criteria, most conducted in Asia and Africa. Results showed consistent associations between exposure to fine particulate matter and adverse outcomes, including increased risks of gestational hypertension, respiratory symptoms, preterm delivery, and low birth weight. Considerable heterogeneity was observed in study design, exposure assessment methods, and confounder adjustment. Despite these limitations, the findings highlight the urgent need for public health interventions to improve indoor air quality in vulnerable settings. Exposure to fine particulate matter (PM2.5) was consistently linked to gestational hypertension, respiratory illness, preterm delivery, and low birth weight. These findings emphasise the urgent need for interventions to reduce indoor pollution exposures in vulnerable populations. This review was not registered, and no external funding was received. Data are available from the corresponding author upon request.