Relationship Between Outdoor Air Pollutant Exposure and Premature Delivery in China- Systematic Review and Meta-Analysis.

Preterm birth (PTB) is considered as a public health problem and one of the main risk factors related to the global disease burden. The purpose of this study aims to explore the influence of exposure to major air pollutants at different pregnancies on PTB. The relationship between air pollutants and PTB in China was collected from cohort studies and case-control studies published before 30 April 2022. Meta-analysis was carried out with STATA 15.0 software. A total of 2,115 papers were retrieved, of which 18 papers met the inclusion criteria. The comprehensive effect of pollutant exposure and PTB were calculated. PM during entire pregnancy and O exposure during third trimester were positively associated with preterm birth. Every 10 μg/m increase in the average concentration of PM during the whole pregnancy will increase the risk of premature delivery by 4%, and every 10 μg/m increase in the average concentration of O in the third trimester will increase the risk of premature delivery by 1%. Exposure to PM entire prenatal pregnancy and O in third trimester is associated with an increased risk of preterm birth occurrence.