Table 3 Bivariate associations of SGA with census dissemination area average income and maternal risk factors
|  | SGA (n = 4237) | Not SGA (n = 54802) |  |
|---|---|---|---|
n (%) | n (%) | n (%) | 2-sided p* |
Average income quintile | Â | Â | Â |
 1 ($6,196–$24,444) | 1018 (24) | 10426 (19) | <0.0001 |
 2 ($24,444–$28,440) | 916 (22) | 10594 (19) |  |
 3 ($28,440–$32,954) | 876 (21) | 11077 (20) |  |
 4 ($32,986–$38,832) | 752 (18) | 11411 (21) |  |
 5 ($38,837–$509,269) | 675 (16) | 11294 (21) |  |
Smoking during pregnancy | 326 (8) | 3152 (6) | <0.0001 |
Maternal age | Â | Â | Â |
 <20 | 75 (2) | 852 (2) | 0.0002 |
 20–35 | 3167 (75) | 39508 (72) |  |
 ≥ 35 | 995 (23) | 14442 (26) |  |
Parity | Â | Â | Â |
 0 | 2784 (66) | 26712 (49) | <0.0001 |
 ≥ 1 | 1453 (34) | 28090 (51) |  |
Pre-pregnancy BMI (kg/m2) | Â | Â | Â |
 Underweight (<18.5) | 531 (13) | 3567 (7) | <0.0001 |
 Normal weight (18.5–25) | 2805 (66) | 34913 (64) |  |
 Overweight (25–30) | 632 (15) | 10862 (20) |  |
 Obese (≥30) | 269 (6) | 5460 (10) |  |
Height (cm) (mean (SD)) | 161 (7) | 164 (7) | <0.0001 |
Diabetes/hypertension | Â | Â | Â |
 Neither | 3422 (81) | 46741 (85) | <0.0001 |
 Diabetes only | 364 (9) | 5251 (10) |  |
 Hypertension only | 390 (9) | 2263 (4) |  |
 Diabetes & hypertension | 61 (1) | 547 (1) |  |
Oligohydramnios | 339 (8) | 1044 (2) | <0.0001 |
Placenta disorder | 135 (3) | 1116 (2) | <0.0001 |