The effect of climate anomalies and ambient air pollution on spontaneous miscarriage in Ghana: Evidence from a national cross-sectional survey

Background: Climate anomalies and ambient air pollutants (AAPs) are linked to adverse pregnancy outcomes, but their impact on spontaneous miscarriage, particularly in sub-Saharan Africa, remains underexplored. This study examines how preconception exposure to climate anomalies, AAPs, and vegetation (measured by the Enhanced Vegetation Index [EVI]) affects spontaneous miscarriage among Ghana women, focusing on EVI’s role as an effect modifier. Methods: Data from the 2017 Ghana Maternal Health Survey were analyzed using Bayesian hierarchical linear and nonlinear clog-log models to assess the relationship between environmental exposures and spontaneous miscarriage. Meteorological data came from the Climatic Research Unit’s gridded Time Series (1960–2017), while AAP and vegetation data were sourced from NASA’s Goddard Earth Sciences Data. The analyses include interaction terms between EVI and environmental exposures. Results: Preconception mean temperature anomalies and carbon monoxide (CO) were strongly associated with increased miscarriage risk (hazard ratio = 4.286 for temperature anomalies and 1.013 for CO). Other AAPs, such as PM 2.5 and ozone, were confounded by climate anomalies and maternal factors. EVI modified the impact of environmental exposures, particularly reducing the effects of temperature anomalies and PM 2.5 on miscarriage risk at higher EVI levels. Conclusions: This study underscores the significant role of climate anomalies and AAPs in increasing spontaneous miscarriage risk in Ghana. The effect modification by EVI highlights vegetation’s potential to mitigate the impact of environmental stressors. These findings stress the need for policies addressing air pollution and climate change to protect maternal health, especially in vulnerable regions.