Associations of ambient air pollutants with pregnancy outcomes in women undergoing assisted reproductive technology and the mediating role of ovarian reserve: A longitudinal study in eastern China

Existing evidence has explored the relationship between exposure to air pollutants with ovarian reserve in women receiving assisted reproductive technology (ART). However, few studies have followed up on ART pregnancy outcomes and evaluated how ovarian reserve is involved in the association between air pollutant exposure and specific ART outcomes. We aimed to determine whether air pollutants affect ART outcomes by interfering with ovarian reserve through long-term follow-up. A total of 5354 women who underwent ART treatment and completed antral follicle count (AFC) detection at the First Affiliated Hospital of University of Science and Technology of China between 2018 and 2020 were involved. Exposure concentrations (0.1° × 0.1°) for three aerodynamic diameters of particulate matter (PM₁, PM_2.5, PM₁₀) and three oxidized pollutants (NO₂, SO₂, O₃) were assigned to each individual according to the latitude and longitude of the participant's residential address. Multivariate linear mixed effects models (LMMs) were performed to estimate the impacts of exposure to air pollutants during the first 6 months of AFC and longer periods on ovarian reserve capacity and ART pregnancy outcomes. Exposure to PM₁ (OR: 0.914, 95%CI: 0.845-0.988), PM_2.5 (OR: 0.908, 95%CI: 0.850-0.970), PM₁₀ (OR: 0.924, 95%CI: 0.865-0.987), and SO₂ (OR: 0.908, 95%CI: 0.843-0.978) was linked with decreased OR for live birth. In addition, with each IQR increase in PM₁, PM_2.5, PM₁₀, SO₂, and NO₂, AFC levels decreased by 0.370, 0.395, 0.064, 0.311, and 0.465, respectively. The mediation effect was more pronounced for NO₂ and SO₂, with AFCs explaining 26.83 % and 9.54 % of their associations with live birth, respectively. Additionally, 6.49 %, 9.16 %, and 6.79 % of live birth failures were ascribed to PM₁, PM_2.5, and PM₁₀, respectively. Findings of this study suggest that exposure to air pollutants may affect reproductive outcomes in women receiving ART by reducing their ovarian reserve capacity.