Analysis Of The Association Between Ambient PM_2.5 Pollution And Adverse Pregnancy Outcomes

Everyone is exposed to different levels of air pollution every day. It has beendemonstrated that air pollution has adverse effects on different periods of human healthof various aspects. Despite the danger of everyone at certain time point is not large, butconsidering continuing exposure crowd is huge, air pollution remains to causetremendous burden of global public health. In recent decades, several countries havereported that air pollution can lead to adverse effects on pregnancy outcomes, and alsocan be enormous harmful to maternal and infant health.Fine particles (fine particulate matter, PM2.5) because of its small size, largespecific surface area, more likely adsorbing chemical substances (toxic heavy metalsetc.) as well as microorganism (bacteria and viruses et) in the air, and characteristic ofhigher reaction and dissolution rate, has become a more harmful air pollutant. Theadverse effects of PM2.5on birth outcomes are worldwide important research at present.A growing body of studies reported the quantitative relationship between the two, butresults are inconsistent, and for whether exposure has a risky time period, the results oftime series analysis are not consistent.Objective: This study aims at conducting a meta-analysis to synthetically quantify theexposure-dose quantitative relationship between PM2.5exposure and adversepregnancy outcomes as well as establishing whether PM2.5exposure can lead toincreased risk of adverse pregnancy outcomes, and providing evidence for if exposurehas higher risky pregnancy period.Methods: I searched Pubmed, Web of Science, Cochrane Library databases of datestliteratures published on March2015, using the Cochrane Collaboration networksystem evaluation method to obtain all papers which studying on quantitativerelationship between PM2.5exposure measurement and adverse pregnancy outcomes.We choose low birth weight, preterm birth, small for gestational age, intrauterinegrowth restriction, hypertensive disorders of pregnancy, premature rupture of membranes as the outcome of adverse pregnancy outcomes. Using the Cochranecollaboration Revman5.3and Stata12.0Meta-analysis software to explore thequantitative relationship.Results: Based on entire pregnancy exposure, a10μg/m3increase in PM2.5waspositively associated with low birth weigh（tOR=1.09；95%CI，1.03-1.15；P<0.05）,preterm birth （OR=1.10；95%CI，1.01-1.20；P<0.05), small for gestational age（OR=1.16；95%CI，1.11-1.20；P<0.01), hypertensive disorders of pregnancy（OR=1.77；95%CI，1.77-2.41；P<0.01), and suggested a potential increase the riskof premature rupture of membranes（OR=1.09，95%CI，1.00-1.19；P=0.05）. Basedon trimester exposure, no significant risks were found in adverse birth outcomes.Publication bias did not occur frequently throughout the study.Conclusion:(1) Based on the whole pregnancy exposure, a10μg/m3increase in PM2.5wasstatistically significant associated with low birth weight, premature birth, smallfor gestational age, and hypertensive disorders of pregnancy, suggested thepossible increase risk of premature rupture of membranes.(2) For the choice of exposure window, we did not observe the obvious evidenceindicating specific exposure period for PM2.5exposure and adverse pregnancyoutcomes.(3) There has been lack of evidence to quantify the relationship between hypertensivedisorders of pregnancy or pre-labor rupture of membranes and PM2.5, moreliteratures are needed.