Table 4 Odds of SGA by census dissemination area average income with and without adjustment for maternal risk factors

Average income quintile

 1 ($6,196–$24,444)

 2 ($24,444–$28,440)

 3 ($28,440–$32,954)

 4 ($32,986–$38,832)

 5 ($38,837–$509,269)

Smoking during pregnancy

 No

Reference

 Yes

1.6 (1.4, 1.8)***

Maternal age

 <20

0.8 (0.6, 1.0)*

 20–35

Reference

 ≥ 35

1.0 (0.9, 1.1)

Parity

 0

Reference

 ≥ 1

0.5 (0.5, 0.6)***

Pre-pregnancy BMI

 Underweight (<18.5)

1.8 (1.6, 2.0)***

 Normal weight (18.5–25)

Reference

 Overweight (25–30)

0.7 (0.7, 0.8)***

 Obese (≥30)

0.6 (0.5, 0.6)***

Height (continuous, cm)

0.9 (0.9, 0.9)***

Diabetes/ Hypertension

 Neither

Reference

 Diabetes only

0.9 (0.8, 1.0)

 Hypertension only

2.4 (2.1, 2.7)***

 Diabetes & hypertension

1.5 (1.1, 2.0)*

Oligohydramnios

 No

Reference

 Yes

3.9 (3.4, 4.4)***

Placenta disorder

 No

Reference

 Yes

1.4 (1.2, 1.7)**