Abstract: Through the review of nearly 40 domestic and foreign literature, the formation, components and toxicity of PM2.5 and its association with adverse birth outcomes (ABOs) including low birth weight (LBW), preterm birth (PTB), stillbirth, gestational diabetes mellitus (GDM) and pre-eclampsia are investigated. PM2.5 mainly consists of element carbon, organic carbon, inorganic matter and heavy metals. Coal burning and traffic are the main sources of urban PM2.5. Heavy metals and polycyclic aromatic hydrocarbons were the main toxic components of PM2.5, which could exert adverse effect on pregnancy outcome through direct placental permeation, affecting maternal endocrine and immune system, inducing oxidative stress or changing genetic materials. At last, there is still mystery about the association of PM2.5 and GDM and pre-eclampsia. Nevertheless, PM2.5 is convincingly thought to be a risk factor of LBW, PTB and stillbirth.

Key words: Air pollutants, Air pollution, Infant, low birth weight, Premature birth, Fetal diseases