Table 4.

Adjusted odds ratio for the association of air pollutants and adverse birth outcomes for every interquartile (IQR)^a increase in exposure after adjustment for co-pollutant effects.

Pollutants	Term LBW^b	PTD^c	VPTD^c
O₃ (ppb)
Trimester 1	0.990 (0.960, 1.021)	1.012 (0.997, 1.028)	1.021 (0.983, 1.061)
Trimester 2	0.960 (0.931, 0.990) ^*	0.990 (0.975, 1.005)	0.985 (0.949, 1.024)
Trimester 3	0.936 (0.907, 0.965) ^*	1.001 (0.986, 1.016)	0.987 (0.943, 1.033)
Pregnancy	0.930 (0.892, 0.970) ^*	1.034 (1.014, 1.055) ^*	1.075 (1.022, 1.131) ^*
PM_2.5 (μg/m³)
Trimester 1	1.013 (0.984, 1.042)	1.030 (1.015, 1.045) ^*	1.053 (1.016, 1.091) ^*
Trimester 2	1.047 (1.018, 1.076) ^*	1.132 (1.117, 1.148) ^*	1.217 (1.177, 1.257) ^*
Trimester 3	1.020 (0.994, 1.047)	1.030 (1.017, 1.044) ^*	1.020 (0.981, 1.061)
Pregnancy	1.026 (1.000, 1.053)	1.052(1.038, 1.066) ^*	1.069 (1.035, 1.105) ^*

Interquartile range for O₃ in ppb: 7.8 for trimester 1, 8.0 for trimester 2, 8.0 for trimester 3, 7.1 for the entire pregnancy; for PM_2.5 in μg/m³: 2.6 for trimester 1, 2.6 for trimester 2, 2.8 for trimester 3, and 2.0 for the entire pregnancy.

Adjusted for maternal education, ethnicity, marital status, age, infant gender, prenatal care status, season of conception, alcohol, smoking, census tract income, urbanicity, presence or absence of maternal risk factor, infection, PTD status, or co morbidity.

Adjusted for maternal education, ethnicity, marital status, age, infant gender, prenatal care status, alcohol, smoking, census group income, urbanicity, presence or absence of maternal risk factor, LBW status, or comorbidity.

Indicates statistical significance at p<0.05