# Table 4 Associations by Exposure Period and Race for Birthweight Percentile for Gestational Age per Interquartile Range Increase in PM2.5 (1.9 μg/m3)a

Longitudinal study population Reference population
Non-Hispanic Black women SIBLING MODEL
(n = 28,782 births to
n = 13,797 women)
NAÏVE MODEL
(n = 28,782 births)
NAÏVE MODEL
(n = 105,262 births)
1st trimester 0.094 (−0.26, 0.45) − 0.035 (− 0.39, 0.31) −0.05 (− 0.28, 0.086)
2nd trimester − 0.011 (− 0.35, 0.33) − 0.12 (− 0.45, 0.21) −0.29 (− 0.46, − 0.11)*
3rd trimester −0.19 (− 0.49, 0.18) −0.37 (− 0.69, − 0.042)* −0.21 (− 0.38, − 0.036)*
Whole pregnancy −0.098 (− 0.57, 0.38) −0.35 (− 0.77, 0.072) −0.35 (− 0.57, − 0.13)*
Non-Hispanic white women SIBLING MODEL
(n = 81,147 births to
n = 39,617women)
NAÏVE MODEL
(n = 81,147 births)
NAÏVE MODEL
(n = 286,381 births)
1st trimester − 0.038 (− 0.25, 0.17) − 0.20 (− 0.40, 0.01) −0.19 (− 0.30, − 0.082)*
2nd trimester −0.34 (− 0.55, − 0.14) −0.38 (− 0.58, − 0.17)* −0.34 (− 0.44, − 0.23)*
3rd trimester −0.31 (− 0.51, − 0.11) −0.45 (− 0.65, − 0.25)* −0.31 (− 0.41, − 0.21)*
Whole pregnancy −0.46 (− 0.74, − 0.17) −0.54 (− 0.80, − 0.29)* −0.43 (− 0.56, − 0.30)*
1. Abbreviations: PM2.5 particulate matter with aerodynamic diameter of < 2.5 μm
2. a Models adjusted for birth order, infant sex, maternal age, maternal educational attainment, maternal smoking during pregnancy, maternal marital status, mean temperature during the corresponding exposure window, and median household income of the census tract of residence
3. *Indicates statistical significance at p < 0.05