The environmental determinant in fertility disparities: Can residential greenness modify the association of oxidants and fine particulate matter with reproductive risks?

Poor Ovarian Response (POR) significantly impairs the success of Assisted Reproductive Technologies (ART). The specific roles of oxidants and fine particulate matter (PM 2.5 ) on female fertility, especially those with POR, remains poorly understood. In this cohort study of 4920 women undergoing ART cycles, we investigated the associations between long-term pre-treatment exposure to oxidants, PM 2.5 , their constituents, and six key reproductive outcomes. Results revealed that elevated oxidants exposure increased risks of pregnancy failure (for each 10 μg/m³ increase in oxidants, odds ratios [OR]=1.238, 95%CI: 1.158, 1.325) and live birth failure (OR=1.330, 95%CI: 1.245, 1.420), with ozone identified as the primary contributor. Exposure to PM 2.5 was significantly linked to an increased risk of POR (for each 10 μg/m³ increase in PM 2.5 exposure, OR=1.249, 95%CI: 1.205, 1.299), with organic matter (OM) being the key constituent. Crucially, residential greenness exerted significant protective effect, associated with reduced risks, accounting for​ 7.44%-17.72% of the observed associations between pollutants and adverse reproductive outcomes through the pathway of reducing oxidants and PM 2.5 . These findings highlight oxidants and PM 2.5 as modifiable risk factors in the fertility equation, and emphasize residential greenness as a potential strategic nature-based intervention to mitigate pollution-related fertility impairment.