Effects of air pollution on female fertility and pregnancy: a review

Air pollution exerts a lot of adverse effects on human health, including on female fertility. However, the exact mechanism of the adverse effects on human fertility is unclear. We conducted a systematic review of previous researches on the influence of air pollution upon female reproduction to fully understand the effect of air pollution on human fertility. The research sites and major pollutants concerned are different among various population epidemiology researches and laboratory studies. The sites of epidemiological investigations included petrochemical plants and traffic roads and the pollutants concerned mainly included particulate matter < 10/2.5 microm in aerodynamic diameter (PM_10/2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃) and other compositions related to coal combustion and traffic exhaust. These studies are mainly based on the evaluation of air pollutants on various stages of egg development, fertilized egg formation and implantation, clinical conception, in vitro fertilization and embryo transfer, abortion, and preterm labor. Despite the bias caused by different design types and many confounding factors, these studies to some extent provide clues for the in-depth study of the mechanism of air pollution's influence on female reproduction.