[Impact of atmospheric particulate matter at different period of gestation on low birth weight: a meta-analysis]

Area of Science:

• Environmental Health
• Reproductive Epidemiology
• Public Health

Background:

• Air pollution, particularly particulate matter (PM), is a growing global concern.
• Adverse birth outcomes, such as low birth weight (LBW), have significant long-term health implications.
• Understanding the specific impacts of different PM sizes (PM2.5 and PM10) during gestation is crucial for public health interventions.

Purpose of the Study:

• To systematically analyze the association between maternal exposure to PM2.5 and PM10 and the risk of low birth weight (LBW).
• To investigate how exposure during different trimesters of gestation influences the risk of LBW.
• To provide a quantitative synthesis of existing evidence through meta-analysis.

Main Methods:

• A systematic literature search was conducted across multiple databases (PubMed, Cochrane Library, Web of Science, etc.) for studies published between 2000 and 2016.
• Keywords included "air pollution", "adverse birth outcomes", "adverse pregnancy outcomes", and "low birth weight/LBW".
• Meta-analysis using the R 3.1.1 Software (Metafor package) was performed on 27 selected studies, including heterogeneity testing, sensitivity analysis, and publication bias adjustment.

Main Results:

• Each 10 μg/m³ increase in PM2.5 was associated with increased odds of LBW: 1st trimester (OR=1.02), 2nd trimester (OR=1.03), 3rd trimester (OR=1.07), and entire gestation (OR=1.09).
• Each 10 μg/m³ increase in PM10 was associated with increased odds of LBW: 1st trimester (OR=1.66), 2nd trimester (OR=1.58), 3rd trimester (OR=1.38), and entire gestation (OR=1.04).
• After adjusting for publication bias, a 10 μg/m³ increase in PM2.5 was associated with a 1.11-fold increased risk of LBW (95% CI: 1.02-1.21).

Conclusions:

• Maternal exposure to both PM2.5 and PM10 during pregnancy is associated with an increased risk of low birth weight.
• The magnitude of the risk associated with PM exposure appears to vary across different trimesters of gestation.
• This meta-analysis underscores the adverse impact of air pollution on fetal development and highlights the need for strategies to mitigate exposure.