Spatially and Temporally Resolved Ambient PM_2.5 in Relation to Preterm Birth

Area of Science:

• Environmental Health
• Reproductive Epidemiology
• Perinatal Studies

Background:

• Maternal exposure to ambient fine particulate matter (PM$_{2.5}$) is increasingly linked to preterm birth (PTB).
• Identifying critical exposure windows is crucial for understanding biological mechanisms and informing public health interventions.
• Few studies have investigated specific gestational windows for PM$_{2.5}$ exposure and PTB risk.

Purpose of the Study:

• To investigate the association between weekly maternal exposure to ambient PM$_{2.5}$ and the odds of preterm birth (PTB).
• To explore potential critical windows of PM$_{2.5}$ exposure during pregnancy.
• To examine sex-specific associations between PM$_{2.5}$ exposure and PTB.

Main Methods:

• Utilized data from 891 mother-newborn pairs in a U.S. pregnancy cohort.
• Estimated daily residential PM$_{2.5}$ concentrations using a satellite-based hybrid model at 1x1 km$^{2}$ resolution.
• Applied Critical Window Variable Selection to assess weekly PM$_{2.5}$ exposure in relation to PTB, with sex-stratified analyses.

Main Results:

• Overall, PM$_{2.5}$ exposure was not associated with an increased odds of PTB across any gestational week.
• Sex-stratified analysis revealed a marginal increase in PTB odds with PM$_{2.5}$ exposure during gestational week 16, specifically among female infants.
• The average PM$_{2.5}$ level during pregnancy was 8.13 ± 1.10 µg/m$^{3}$.

Conclusions:

• This study did not find strong evidence supporting a general association between weekly PM$_{2.5}$ exposure and preterm birth.
• A potential sex-specific, critical window effect at week 16 warrants further investigation.
• Findings suggest current PM$_{2.5}$ levels in this cohort may not pose a significant risk for PTB.