Table 6

Maternal risk factors by census dissemination area income quintile
Census dissemination area average income quintile
1 (lowest) 2 3 4 5 (highest) 2-sided p
n 11444 11510 11953 12163 11969
n (%)
Smoking during pregnancy 690 (6) 807 (7) 815 (7) 698 (6) 468 (4) <0.0001
Maternal age
 <20 269 (2) 211 (2) 201 (2) 144 (1) 102 (1) <0.0001
 20–35 8714 (76) 8667 (75) 8827 (74) 8738 (72) 7729 (65)
 ≥ 35 2461 (22) 2632 (23) 2925 (24) 3281 (27) 4138 (35)
Parity ≥ 1 5713 (50) 5643 (49) 5979 (50) 6119 (50) 6089 (51) .0760
Pre-pregnancy BMI
 Underweight (<18.5) 1092 (10) 878 (8) 772 (6) 691 (6) 665 (6) <0.0001
 Normal weight (18.5–25) 7190 (63) 7167 (62) 7355 (62) 7727 (64) 8279 (69)
 Overweight (25–30) 2144 (19) 2278 (20) 2464 (21) 2471 (20) 2137 (18)
 Obese (≥30) 1018 (9) 1187 (10) 1362 (11) 1274 (10) 888 (7)
Height (cm) – Mean (SD) 162 (7) 163 (7) 164 (7) 165 (7) 165 (7) <0.0001
Diabetes/ Hypertension
 Neither 9388 (82) 9592 (83) 10061 (84) 10493 (86) 10629 (89) <0.0001
 Diabetes only 1444 (13) 1270 (11) 1188 (10) 984 (8) 729 (6)
 Hypertension only 463 (4) 512 (4) 563 (5) 577 (5) 538 (4)
 Diabetes & hypertension 149 (1) 136 (1) 141 (1) 109 (1) 73 (1)
Oligohydramnios 308 (3) 281 (2) 264 (2) 258 (2) 272 (2) 0.0345
Placenta disorder 238 (2) 274 (2) 239 (2) 245 (2) 255 (2) 0.2528

Average income quintile ranges: quintile 1, $6,196–$24,444; quintile 2, $24,445–28,440; quintile 3, 28,441–$32,954; quintile 4, $32,987–$38,832; quintile 5, $38,838–$509,269. 2-sided p value is for chi squared test except for height, which is for analysis of variance (ANOVA).

Hayward et al.

Hayward et al. BMC Public Health 2012 12:333   doi:10.1186/1471-2458-12-333

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