Association between exposure to particulate matter during pregnancy and birthweight: a systematic review and a metaanalysis of birth cohort studies

Abstract

Studies of the associations between maternal exposure to particulate matter (PM) and risk of adverse effects on fetal growth are inconsistent and inconclusive. This question can be well answered by carefully designed birth cohort studies; however, so far the evidence from such studies has not come to the same conclusion. We sought to evaluate the association between maternal exposures to PM and low birthweight (LBW) enrolling 14 studies from 11 centers, and to explore the influence of trimester and exposure assessment methods on between-center heterogeneity in this association. Data were derived from PubMed, Embase, Google Scholar, CNKI, and WanFang database, references from relevant articles, and results from published studies until March 2017. Using a random-effects meta-analysis, we combined the coefficient and odds ratios (OR) of individual studies conducted among 14 birth cohort studies. Random-effect meta-analysis results suggested that a 17% and 6% increase in risk of LBW was relevant to a 10 mg/m rise in PM and PM exposure concentrations at the 3rd trimester (pooled odds ratios (OR), 1.17 and 1.06; 95% confidence interval (CI), 0.94-1.46 and 0.97-1.15, respectively), but the null value was included in our 95% CI. Our results showed that exposure to PM and PM during pregnancy has a positive relevance to LBW based on birth cohort studies. However, neither reached formal statistical significance. Negative impacts on outcomes of birth is implied by maternal exposure to PM. Further mechanistic researches are needed to explain the connection between PM pollution and LBW.

Perinatal Health Inequalities in the Industrial Region of Estonia: A Birth Registry-Based Study

“…The current study showed a positive but statistically non-significant association between prenatal PM 10 exposure and ABOs, which is consistent with the existing evidence on non-significant association [ 72 , 74 ]. Despite the inconsistent results shown by earlier reviews [ 72 , 74 , 75 ], according to the recent review [ 26 ], a number of studies conducted in the ICS have shown a significant association between PM 10 and PTB [ 18 , 27 , 29 , 35 ] and LBW [ 27 , 29 , 32 , 33 , 53 ]. One of the reasons for the currently established non-significant association with PM 10 could be that the average annual concentration is on the borderline of the recommended air quality guideline by WHO [ 71 ].…”

“…Similarly, the systematic review by Sapkota et al [ 72 ] found that PM 2.5 exposure during the first trimester increased the PTB risks, while the LBW results were inconclusive. On the other hand, the comprehensive review by Klepac et al [ 73 ] reported heterogeneity with both first and third-trimester exposure and PTB, whereas the review and meta-analysis by Ji et al [ 74 ] showed a higher publication bias on the association between LBW and third-trimester PM 2.5 exposure. Thus, studies seem to have a heterogenous association with ABOs on the trimester-specific PM 2.5 exposure.…”

Association between maternal exposure to particulate matter (PM2.5) and adverse pregnancy outcomes in Lima, Peru

“…Three prior meta-analyses [12,13,24] found the higher PM 2.5 was associated with higher risk of LBW or TLBW. Our results for TLBW are generally consistent with these reviews.…”