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Table 4 Trimester-specific odds ratios (OR)* of low birth weight and premature birth for pollution exposure

From: Maternal exposure to low-level air pollution and pregnancy outcomes: a population-based study

Pollutant Low birth weight Preterm birth
  Single pollutant model Multiple pollutant model† Single pollutant model Multiple pollutant model†
  OR (95% CI) OR (95% CI) OR 95% CI OR 95% CI
Formaldehyde(per 5 μg/m3 increase in concentration)
1st trimester 2.20 (1.00–4.85) 2.39 (1.07–5.32) 1.13 (0.64–1.97) 0.91 (0.49–1.68)
2nd trimester 1.48 (0.65–3.40) 1.57 (0.68–3.64) 0.46 (0.27–0.78) 0.38 (0.21–0.67)
3rd trimester 1.29 (0.62–2.73) 1.17 (0.52–2.65) 1.01 (0.64–1.59) 0.94 (0.57–1.53)
NO2 (per 10 μg/m3 increase in concentration)
1st trimester 0.91 (0.53–1.56) 0.79 (0.45–1.39) 1.67 (1.28–2.18) 1.69 (1.28–2.23)
2nd trimester 0.93 (0.61–1.41) 0.88 (0.57–1.36) 1.13 (0.90–1.40) 1.30 (1.03–1.64)
3rd trimester 1.34 (0.94–1.92) 1.32 (0.92–1.91) 1.19 (0.96–1.47) 1.19 (0.96–1.49)
  1. * odds ratio adjusted for gestational age (low birth weight model only), parity, maternal age (≤ 19, 20–29, 30–34, ≥ 35), marital status, education, season of birth, maternal and paternal smoking † also adjusted for the other air pollutant assessed