Particulate matter 2.5 exposure during pregnancy and birth outcomes: Evidence from Colombia.

Particulate matter is a type of air pollution that consists of fine particles with a diameter <2.5 μm (PM), which can easily penetrate the respiratory system and enter the bloodstream, increasing health risks for pregnant women and their unborn babies. Recent reports have suggested that there is a positive association between PM exposure and adverse pregnancy outcomes. However, most evidence of this relationship comes from Western countries. Thus, the objective of this study was to evaluate the association between PM exposure during pregnancy and birth outcomes among pregnant women in Colombia. This study included 542,800 singletons born in 2019 to Colombian women, aged 15+ years, residing in 981 municipalities. Data on parental, child and birth characteristics were extracted from anonymized live birth records. Satellite-based estimates of monthly PM concentrations at the surface level were extracted for each municipality from the Atmospheric Composition Analysis Group (ACAG). PM exposure during pregnancy was indicated by the monthly average of PM concentrations across the pregnancy duration for the municipality where the child was born. The associations of municipality-level PM concentration during pregnancy with pre-term birth (PTB) and low birth weight (LBW) were tested in separate two-level logistic regression models, with babies nested within municipalities. The prevalence of PTB and LBW were 8.6 % and 8.3 %, respectively. The mean PM concentration across the 981 municipalities was 18.26 ± 3.30 μg/m, ranging from 9.11 to 31.44 μg/m. Greater PM concentration at municipality level was associated with greater odds of PTB (1.05; 95%CI: 1.04-1.06) and LBW (1.04; 95%CI: 1.03-1.05), after adjustment for confounders. Our findings provide new evidence on the association between PM on adverse pregnancy outcomes from a middle-income country.