Table 1 Socio-demographics of sample population and target population
| Survey Participants n (%) | Target Population n (%) | P-value* | |
|---|---|---|---|
| Maternal Characteristics | n = 3341 | n = 10,131 | |
| Age, years | (missing = 103) | ||
| < 20 years | 27 (0.8) | 354 (3.4) | < 0.0001 |
| 20–29 years | 1065 (32.9) | 4432 (43.1) | |
| 30–39 years | 1982 (61.2) | 5066 (49.2) | |
| ≥ 40 years | 164 (5.1) | 435 (4.2) | |
| Parity | (missing = 51) | ||
| Primiparous | 1496 (45.5) | 3079 (30.4) | < 0.0001 |
| Multiparous | 1794 (55.5) | 7052 (69.6) | |
| Marital status | (missing = 57) | (missing = 15) | |
| Partnered [married/de facto] | 3125 (95.2) | 8120 (80.3) | < 0.0001 |
| Single [never married, separated/divorced, widowed, not stated] | 159 (4.8) | 2046 (19.7) | |
| Country of birth | (missing = 57) | (missing = 1) | |
| Australia | 2554 (77.8) | 7386 (72.9) | < 0.0001 |
| Overseas | 730 (22.2) | 2744 (27.1) | |
| Indigenous status | (missing = 74) | ||
| Neither Aboriginal nor Torres Strait Islander | 3205 (98.1) | 9411 (92.9) | < 0.0001 |
| Aboriginal and/or Torres Strait Islander | 62 (1.9) | 720 (7.1) | |
| Smoking status | (missing = 59) | (missing = 21) | |
| Smoked during pregnancy | 135 (4.1) | 1216 (12.0) | < 0.0001 |
| Smoke-free during pregnancy | 3147 (95.9) | 8894 (88.0) | |
| Infant Characteristics | n = 3341 | n = 10,287 | |
| Sex | (missing = 29) | ||
| Female | 1552 (53.1) | 4881 (47.4) | 0.41 |
| Male | 1760 (46.9) | 5406 (52.6) | |
| Birth weight, g | (missing = 147) | (missing = 19) | |
| < 2500 | 169 (5.3) | 700 (6.8) | < 0.0003 |
| 2500–3499 | 1632 (51.1) | 5444 (52.9) | |
| 3500–3999 | 1012 (31.7) | 3078 (29.9) | |
| 4000–4499 | 323 (10.1) | 938 (9.1) | |
| ≥ 4500 | 58 (1.8) | 127 (1.2) | |
| Gestation | (missing = 55) | ||
| Term ≥37 weeks | 3074 (93.5) | 9400 (91.4) | < 0.0001 |
| Preterm < 37 weeks | 212 (6.5) | 887 (8.6) | |
| Plurality | (missing = 74) | ||
| Singleton | 3220 (98.6) | 9976 (97.0) | < 0.0001 |
| Multiple | 47 (1.4) | 311 (3.0) | |
| Indigenous status | (missing = 61) | ||
| Neither Aboriginal nor Torres Strait Islander | 3166 (96.5) | 9382 (91.2) | < 0.0001 |
| Aboriginal and/or Torres Strait Islander | 114 (3.5) | 905 (8.8) |