| Nonasthmatic# | Asthmatic¶ | |||
| Nonsmokers | Smokers | Nonsmokers | Smokers | |
| Subjects | 133 271 (82.7) | 27 869 (17.3) | 8333 (74.6) | 2832 (25.4) |
| Maternal age years | 30.4±5.3 | 27.8±6.0 | 29.4±5.6 | 26.7±6.0 |
| <20 | 4814 (3.6) | 3010 (10.8) | 502 (6.0) | 408 (14.4) |
| 20–24 | 17 421 (13.1) | 7178 (25.8) | 1523 (18.3) | 815 (28.8) |
| 25–29 | 39 276 (29.5) | 7799 (28.0) | 2578 (31.0) | 802 (28.3) |
| 30–34 | 45 964 (34.5) | 6234 (22.4) | 2426 (29.1) | 522 (18.4) |
| ≥35 | 24 720 (18.5) | 3648 (13.0) | 1304 (15.6) | 285 (10.1) |
| Ethnicity | ||||
| Caucasian | 119 610 (89.7) | 25 128 (90.2) | 7892 (94.7) | 2586 (91.3) |
| Aboriginal/TSI | 1813 (1.4) | 2208 (7.9) | 151 (1.8) | 200 (7.1) |
| Asian | 8512 (6.4) | 222 (0.7) | 178 (2.1) | 18 (0.6) |
| Other | 3336 (2.5) | 311 (1.1) | 112 (1.3) | 28 (1.0) |
| Born in Australia | 109 297 (82.0) | 25 710 (92.3) | 7541 (90.5) | 2657 (93.8) |
| Socioeconomic index for areas | ||||
| Quintile 1 (lowest) | 28 533 (21.4) | 11 293 (40.5) | 1964 (23.6) | 1284 (45.3) |
| Quintile 2 | 29 874 (22.4) | 7598 (27.3) | 1978 (23.8) | 732 (25.8) |
| Quintile 3 | 25 447 (19.1) | 4395 (15.8) | 1607 (19.3) | 440 (15.5) |
| Quintile 4 | 29 824 (22.4) | 3395 (12.2) | 1787 (21.4) | 284 (10.0) |
| Quintile 5 | 19 501 (14.6) | 1168 (4.2) | 992 (11.9) | 92 (3.2) |
| Unknown | 92 (0.1) | 20 (<0.01) | 5 (<0.01) | 0 |
| Hospital classification | ||||
| Private | 84 371 (63.3) | 25 672 (92.1) | 5497 (66.0) | 2697 (95.2) |
| Public | 48 900 (36.7) | 2197 (7.9) | 2836 (34.0) | 135 (4.8) |
| Parity | ||||
| 0 | 57 193 (42.9) | 9576 (34.4) | 4043 (48.5) | 1036 (36.6) |
| 1 | 48 149 (36.1) | 8816 (31.6) | 2715 (32.6) | 812 (28.7) |
| 2 | 19 154 (14.4) | 5134 (18.4) | 1058 (12.7) | 491 (17.3) |
| ≥3 | 8775 (6.6) | 4343 (15.6) | 517 (6.2) | 493 (17.4) |
| Cigarettes smoked per day in second half of pregnancy | ||||
| 1–10 | 17 697 (63.5) | 1613 (57.0) | ||
| 11–20 | 8464 (30.4) | 944 (33.3) | ||
| ≥21 | 1706 (6.1) | 275 (9.7) | ||
Data are presented as n (%) or mean±sd. TSI: Torres Strait Islander. #: n=161 140 (93.3%); ¶: n=11 165 (6.7%).