Air Pollution Impact on Pregnancy Outcomes in Como, Italy

Objective: This retrospective observational study investigates the association between maternal exposure to air pollutants and pregnancy adverse outcomes in low urbanization areas. Methods: We used multivariate regression analysis to estimate, in the Como province (2005-2012), the effects of NOx, NO2, SO2, O-3, CO, and PM10 on low birth weight (LBW), babies small for gestational age (SGA), and preterm birth (PTB). Results: PTB was inversely associated with high (5.5 mu g/m(3)) exposure to SO2 (adjusted odds ratio [aOR] = 0.74, 95% confidence interval [95% CI] = 0.58-0.95) and to CO (1.8 mg/m(3), aOR = 0.84, CI = 0.72-0.99). PTB risk increased with second trimester exposure to NOx (118.3 mu g/m(3), aOR = 1.53, CI = 1.25-1.87), while LBW risk increased with third trimester PM10 (56.1 mu g/m(3), aOR = 1.44, CI = 1.03-2.02). SGA was inversely associated with third trimester NOx (115.8 mu g/m(3), aOR = 0.89, CI = 0.79-0.99). Conclusions: Exposure to SO2 and CO seems to postpone delivery: a longer gestation could compensate for maternal hypoxemic-hypoxic damage.