Air pollution and birth outcomes: a systematic review
Prakesh S Shah1, Taiba Balkhair,
1Department of Pediatrics, Mount Sinai Hospital, Toronto, Ontario, Canada. pshah@mtsinai.on.ca
Environment International
|November 30, 2010
Summary
Exposure to specific air pollutants like fine particulate matter is linked to adverse birth outcomes, including low birth weight and preterm birth. Further research is needed to clarify these associations.
Area of Science:
- Environmental Health
- Reproductive Epidemiology
- Toxicology
Background:
- Maternal exposure to air pollutants is suspected to cause adverse birth outcomes through various mechanisms.
- These mechanisms include inflammation, direct fetal/placental toxicity, altered oxygen transport, and DNA damage.
Purpose of the Study:
- To systematically review the scientific literature on the association between air pollutants and birth outcomes.
- Specifically examining low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA) births.
Main Methods:
- A comprehensive search of electronic databases and bibliographies was conducted for relevant English-language studies.
- Included studies underwent rigorous risk of bias assessment, focusing on selection, exposure, confounders, analysis, and outcomes.
- Unadjusted and adjusted effect estimates were extracted and methodological differences were evaluated.
Main Results:
- Forty-one studies met eligibility criteria, with many exhibiting moderate risk of bias due to indirect exposure assessment.
- Sulfur dioxide exposure was linked to PTB; fine particulate matter (≤2.5 μM) associated with LBW, PTB, and SGA.
- Coarse particulate matter (≤10 μM) was associated with SGA births, while evidence for other pollutants was inconclusive.
Conclusions:
- Published studies show heterogeneous associations between air pollutants and birth outcomes, potentially due to exposure quantification challenges and study design limitations.
- Improved methods for assessing exposure duration, intensity, and population-wide effects are crucial for future research.
- Well-designed nested studies addressing confounding and residential mobility are needed to clarify these complex relationships.
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