Table 1.
Maternal characteristics by smoking status in BC, 2001-2006
| Births by smoking status,* % | ||||||||
|---|---|---|---|---|---|---|---|---|
| Never | Former | 1-4 | 5-9 | 10 + | Missing | Total (% missing) | ||
| Characteristic | n = 197,583 | n = 12,256 | n = 7,806 | n = 5,839 | n = 10,407 | n = 2,512 | n = 236,403 (1.1) | |
| Maternal Age | < 20 | 2.3 | 7.8 | 14.0 | 12.2 | 9.2 | 11.8 | 8,620 (3.5) |
| 20-24 | 12.4 | 24.3 | 32.4 | 32.7 | 30.3 | 29.0 | 35,817 (2.0) | |
| 25-29 | 27.9 | 29.5 | 26.8 | 27.2 | 26.8 | 25.7 | 65,877 (1.0) | |
| 30-34 | 34.7 | 24.5 | 17.4 | 17.3 | 20.3 | 21.1 | 76,616 (0.7) | |
| 35-39 | 18.7 | 11.5 | 7.7 | 8.8 | 10.8 | 10.1 | 40,808 (0.6) | |
| 40+ | 4.0 | 2.4 | 1.7 | 1.8 | 2.5 | 2.2 | 8,665 (0.7) | |
| Parity ≥ 1 | No | 44.3 | 59.3 | 54.7 | 47.3 | 40.2 | 52.5 | 107,381 (1.2) |
| Yes | 55.7 | 40.7 | 45.3 | 52.7 | 59.8 | 47.5 | 129,022 (0.9) | |
| Single Parent | No | 92.7 | 87.1 | 76.5 | 77.8 | 75.1 | 75.6 | 214,054 (0.9) |
| Yes | 3.7 | 8.7 | 15.0 | 15.1 | 16.7 | 18.3 | 12,726 (3.6) | |
| Unknown | 3.6 | 4.1 | 8.6 | 7.1 | 8.2 | 6.1 | 9,623 (1.6) | |
| Has Grade 12† | No | 0.8 | 3.0 | 5.2 | 5.2 | 5.4 | 3.1 | 3,301 (0.7) |
| Yes | 10.7 | 12.9 | 9.6 | 9.4 | 6.5 | 6.7 | 24,908 (2.4) | |
| missing | 88.5 | 84.1 | 85.2 | 85.4 | 88.1 | 90.2 | 208,194 (1.1) | |
| Gestational | No | 93.3 | 94.6 | 96.2 | 95.8 | 95.1 | 94.7 | 221,256 (1.1) |
| diabetes | Yes | 6.7 | 5.4 | 3.8 | 4.2 | 4.9 | 5.3 | 15,147 (0.9) |
| Pre-existing Diabetes | No | 99.6 | 99.7 | 99.6 | 99.6 | 99.4 | 99.6 | 235,465 (1.1) |
| Yes | 0.4 | 0.3 | 0.4 | 0.4 | 0.6 | 0.4 | 938 (1.2) | |
| Hypertension in pregnancy | No | 97.8 | 97.1 | 98.1 | 98.0 | 98.2 | 97.8 | 228,674 (1.1) |
| Yes | 2.2 | 3.0 | 1.9 | 2.0 | 1.8 | 2.2 | 5,272 (1.0) | |
| Indication of Alcohol Use | No | 99.7 | 98.1 | 95.9 | 96.6 | 95.1 | 93.8 | 234,290 (1.0) |
| Yes | 0.4 | 1.9 | 4.1 | 3.4 | 4.9 | 6.3 | 2,113 (7.4) | |
| Indication of Drug Use | No | 99.2 | 96.9 | 90.8 | 90.3 | 84.6 | 86.7 | 231,267 (0.9) |
| Yes | 0.8 | 3.1 | 9.2 | 9.7 | 15.4 | 13.1 | 5,136 (6.4) | |
| Pre-pregnancy weight | < 55 | 21.0 | 16.4 | 19.0 | 19.9 | 18.8 | 16.4 | 48,430 (0.9) |
| 55-74 | 42.9 | 43.6 | 38.8 | 38.6 | 36.2 | 35.0 | 99,973 (0.9) | |
| > 74 | 14.7 | 22.0 | 18.1 | 18.4 | 20.3 | 16.7 | 36,720 (1.1) | |
| missing | 21.5 | 18.1 | 24.1 | 23.1 | 24.7 | 31.8 | 51,280 (1.6) | |
| Prenatal Care Visits | ≥ 3 | 92.1 | 93.4 | 92.3 | 91.2 | 89.5 | 85.9 | 217,461 (1.0) |
| < 3 | 1.2 | 1.2 | 2.5 | 3.0 | 3.4 | 3.8 | 3,364 (2.9) | |
| missing | 6.7 | 5.5 | 5.2 | 5.8 | 7.1 | 10.3 | 15,578 (1.7) | |
* Likelihood-Ratio Chi-squared tests for independence across the 5 smoking categories were all significant at p < 0.05, except pre-existing diabetes (p = 0.06).
† Maternal education was measured in years of education with '12 years' indicating high school education.