Mapping the Global Evidence on Environmental and Climatic Factors Linked to Human Fertility-Related Outcomes: Protocol for a Scoping Review.

Background: Increasing attention has been directed toward environmental and climatic exposures as potential factors influencing reproductive function and fertility-related outcomes. However, the available evidence is dispersed across populations, study designs, and exposures. Objective: The primary objective of this scoping review is to map and synthesize the extent, range, and nature of the global evidence on how environmental and climatic factors influence human fertility outcomes. We aim to capture the environmental and climatic exposures that have been studied, characterize the fertility-related outcomes assessed, and summarize the associations reported between these exposures and outcomes. Methods: The present scoping review will systematically map global evidence on environmental and climatic factors in relation to human fertility-related outcomes. We will include human studies examining associations between environmental or climatic exposures and fertility-related outcomes, including measures of reproductive function, fertility potential, and reproductive success. A comprehensive search will be conducted across major electronic databases, including PubMed, Embase, Web of Science, and the Cochrane Library. Covidence will be used for screening and data management. Reviewers will independently screen studies for eligibility, with disagreements resolved through discussion or consultation with a third reviewer. Data will be extracted using a standardized form, which will be piloted and refined. Furthermore, the methodological quality of included studies will be appraised using the relevant JBI critical appraisal checklist according to study design. Findings will be synthesized using narrative synthesis, structured tables, and appropriate visual methods. The review will be reported in accordance with the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) guidelines. Results: Title and abstract screening was completed in May 2026, and full-text screening is underway. Data extraction and synthesis will be conducted after completion of study selection. The review will provide a structured synthesis of available human evidence, summarizing the range of environmental and climatic exposures studied, fertility-related outcomes assessed, and characteristics of included studies. It will also describe the direction and significance of reported findings, including consistent, mixed, or inconclusive evidence, and identify key gaps in the literature to inform future research priorities. Conclusions: As global fecundity trends evolve and concerns about environmental exposures and climate change intensify, understanding how the environment influences reproductive potential is urgent. This work aligns with global development priorities by addressing the intersection of Sustainable Development Goals 3 (good health and well-being) and 13 (climate action).