Air pollution and female reproductive traits: insights from bibliometrics and Mendelian randomization

This study employed a dual-method approach integrating bibliometric analysis and Mendelian randomization (MR) to investigate the relationship between air pollution and female reproductive traits. A bibliometric analysis of the Web of Science database (up to May 2025) identified a marked increase in research output after 2010, with China, the USA, and the UK as the leading contributors. The analysis highlighted key mechanistic themes, including oxidative stress, endocrine disruption, and emerging interest in epigenetic mechanisms. Using MR to explore potential genetic links, we found that in individuals of European ancestry, genetically predicted exposure to PM2.5 was associated with a later age at first birth (AFB) and first live birth (AFLB). PM2.5-10 and PM10 were associated with AFB, while NOx was linked to later timing of AFLB, last live birth (ALLB), first sexual intercourse (AFS), and natural menopause (ANM) (all *p* < 0.05). In the African ancestry cohort, more limited but notable signals were observed: PM2.5-10 was associated with an earlier age at menarche (AAM), and NOx with later AFLB and ALLB. All findings were supported by sensitivity analyses showing no evidence of pleiotropy.