Table 3 Odds Ratios by Exposure Period and Race for Small for Gestational Age (SGA) Births per Interquartile Range Increase in PM_2.5 (1.9 μg/m³)^a

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

1.01 (0.96, 1.06)

1.01 (0.97, 1.04)

1.01 (0.98, 1.02)

 2nd trimester

1.02 (0.97, 1.07)

1.02 (0.98, 1.05)

1.02 (1.00, 1.03)

 3rd trimester

1.05 (1.00, 1.10)

1.04 (1.01, 1.08)*

1.03 (1.01, 1.05)*

 Whole pregnancy

1.04 (0.98, 1.11)

1.04 (1.00, 1.09)

1.03 (1.00, 1.05)

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

1.08 (1.03, 1.12)*

1.07 (1.03, 1.10)*

1.03 (1.02, 1.05)*

 2nd trimester

1.06 (1.02, 1.10)*

1.05 (1.02, 1.08)*

1.04 (1.02, 1.06)*

 3rd trimester

1.06 (1.02, 1.11)*

1.06 (1.03, 1.09)*

1.04 (1.02, 1.05)*

 Whole pregnancy

1.11 (1.06, 1.18)*

1.09 (1.05, 1.14)*

1.06 (1.04, 1.08)*