Association of combined exposure to air pollutants during ovarian stimulation, follicular fluid metabolites, and IVF/ICSI outcomes: A prospective cohort study.
Xu. Song S; Li. Yuehong Y; Xiang. Hanyu H; Sun. Yan Y; Zhang. Jie J
Key Findings
- Higher ozone (O3) and fine particulate matter (PM2.5) exposure during ovarian stimulation reduced fertilization rates and the proportion of top‑quality embryos.
- PM2.5 exposure was also associated with lower clinical pregnancy and live‑birth rates.
- Four follicular‑fluid metabolites (pregnenolone, 7‑dehydrodesmosterol, oleic acid, deoxyuridine monophosphate) partially mediated the negative effects, pointing to disrupted steroid production, oxidative balance, and DNA damage.
Practical Outcomes
- For biohackers and DIY fertility enthusiasts, the takeaway is to minimize exposure to air pollution during IVF cycles—use high‑efficiency air filters, stay indoors on high‑pollution days, and consider timing cycles when air quality is better. The findings don’t change how gonadorelin is used, but they highlight environmental factors that can impact reproductive success.
Summary
This study looked at how breathing polluted air while women are undergoing IVF affects the eggs and embryos. It found that higher levels of ozone and fine particles (PM2.5) were linked to fewer fertilized eggs, lower‑quality embryos, and reduced chances of pregnancy and live birth. Certain chemicals in the fluid around the egg seemed to explain part of this damage.
Abstract
The impact of ambient air pollution on female fertility, particularly under real-world multipollutant exposure scenarios and regarding embryo quality, remains poorly understood. The underlying biological mechanisms have yet to be fully elucidated. Follicular fluid (FF) metabolites, reflecting the oocyte microenvironment, may provide mechanistic insights into air pollution toxicity. In this prospective cohort study, 688 women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) were enrolled. Individual-level exposures to six air pollutants [particulate matter with aerodynamic diameter ≤ 2.5 μm (PM<sub>2.5</sub>); particulate matter with aerodynamic diameter ≤ 10 μm (PM<sub>10</sub>); ozone (O<sub>3</sub>); nitrogen dioxide (NO<sub>2</sub>); sulfur dioxide (SO<sub>2</sub>); carbon monoxide (CO)] were averaged over each participant's controlled ovarian stimulation (COS) window. Composite air pollution scores (CAPS) were constructed for IVF/ICSI outcomes. Untargeted FF metabolomics was performed using ultra-performance liquid chromatography coupled with high-resolution mass spectrometry. Associations between pollutant exposure, CAPS, and IVF/ICSI outcomes were assessed using generalized linear models, and mediation analysis was conducted to identify FF metabolites involved. Elevated levels of O<sub>3</sub> and PM<sub>2.5</sub> were associated with lower proportions of fertilization and best-quality embryo. PM<sub>2.5</sub> was also inversely associated with clinical pregnancy and live birth proportions. CAPS demonstrated consistent negative associations, especially in nulliparity, IVF treatment, and gonadotropin-releasing hormone antagonist protocol participants, with variations across age and body mass index. Mediation analysis identified four FF metabolites-pregnenolone, 7-dehydrodesmosterol, oleic acid, and deoxyuridine monophosphate-as partial mediators. These metabolites participate in steroid biosynthesis, oxidative balance, and DNA damage pathways, providing novel mechanistic insights into the reproductive toxicity of ambient air pollution.
Study Information
pubmed
2025
2025-10-07T00:00:00.000Z
10.1016/j.jhazmat.2025.140067
56