Table 3 Unadjusted and adjusted linear regression results for black smoke (per 10 gm³) in relation to all three outcome measures, by exposure window

Whole pregnancy

Birth weight (g)

-3.4 (-3.9, -2.9)

< 0.00001

-1.7 (-2.4 -0.9)

< 0.00001

Gestational age (wks)

0.02 (0.01, 0.02)

< 0.0001

0.001 (-0.003, 0.004)

0.667

Standardized birth weight

-0.01 (-0.01; -0.01)

< 0.0001

-0.002 (-0.004 -0.0003)

0.020

Trimester 1

Birth weight (g)

-0.2 (-2.4, -1.6)

< 0.0001

-0.2 (-0.7, 0.3)

0.497

Gestational age (wks)

0.01 (0.01, 0.02)

< 0.0001

0.004 (0.002, 0.006)

< 0.0001

Standardized birth weight

-0.007 (-0.008 -0.006)

< 0.0001

0.0003 (-0.0009; 0.001)

0.657

Trimester 2

Birth weight (g)

-2.7 (-3.1, -2.3)

< 0.0001

-1.5 (-2.0, -0.9)

< 0.0001

Gestational age (wks)

0.01 (0.01, 0.02)

< 0.0001

0.003 (0.001, 0.006)

0.006

Standardized birth weight

-0.008(-0.009 -0.007)

< 0.0001

-0.002 (003; -0.001)

< 0.0001

Trimester 3

Birth weight (g)

-3.0 (-3.4, -2.5)

< 0.0001

-0.7 (-1.2, -0.2)

0.012

Gestational age (wks)

0.01 (0.01, 0.02)

< 0.0001

-0.01(-0.01, -0.003)

< 0.0001

Standardized birth weight

-0.008(-0.008; -0.007)

< 0.0001

-0.0008 (-0.002, 0.0004)

0.203