Smoking behaviours reported in pregnancy and the postpartum adjusted for non-response at late pregnancy and 3 months postpartum using multiple imputation
| Characteristic | Baseline (early pregnancy) | Late pregnancy | Postpartum | ||||
| n | % | 95% CI | % | 95% CI | % | 95% CI | |
| Current smokers* | 488 | 57.4 | 54.1 to 60.7 | 59.1 | 54.9 to 63.4 | 67.1 | 62.7 to 71.5 |
| Reported quit attempt since learning of pregnancy/previous questionnaire/birth of baby† | |||||||
| Yes | 272 | 55.7 | 51.3 to 60.1 | 51.3 | 44.7 to 58.0 | 27.4 | 21.7 to 33.2 |
| No | 200 | 41.0 | 36.7 to 45.4 | 48.7 | 42.0 to 55.3 | 72.6 | 66.8 to 78.3 |
| If have made a quit attempt, attempt lasted at least 24 hours | |||||||
| Yes | 178 | 65.4 | 59.6 to 71.0 | 78.9 | 71.6 to 86.2 | 67.8 | 55.8 to 79.8 |
| No | 90 | 33.1 | 27.7 to 38.9 | 21.1 | 13.8 to 28.4 | 32.2 | 20.2 to 44.2 |
| Cigarettes per day | |||||||
| 0–10 | 342 | 70.1 | 65.9 to 74.0 | 68.3 | 63.2 to 73.3 | 60.0 | 54.3 to 65.7 |
| ≥11 | 131 | 26.8 | 23.1 to 31.0 | 31.6 | 26.6 to 36.7 | 40.0 | 34.3 to 45.7 |
| How soon after waking smoke first cigarette, min | |||||||
| ≤30 | 260 | 53.3 | 48.8 to 57.7 | 48.6 | 43.1 to 54.2 | 48.2 | 41.8 to 54.6 |
| ≥31 | 206 | 42.2 | 37.9 to 46.7 | 51.4 | 45.8 to 56.9 | 51.8 | 45.4 to 58.2 |
| Heaviness of Smoking Index | |||||||
| Low dependence (0–2) | 310 | 63.5 | 59.1 to 67.7 | 68.1 | 62.5 to 73.8 | 65.7 | 59.1 to 72.3 |
| Moderate-to-high dependence (3–6) | 154 | 32.6 | 27.6 to 35.8 | 31.9 | 26.2 to 37.5 | 34.3 | 27.7 to 40.9 |
| Intention to quit smoking | |||||||
| Intending to quit within next 30 days | 197 | 40.4 | 36.1 to 44.8 | 29.7 | 23.8 to 35.6 | 14.2 | 10.0 to 18.3 |
| Intending to quit within next 3 months/not seriously planning to quit | 252 | 51.6 | 47.2 to 56.1 | 70.3 | 64.4 to 76.2 | 85.8 | 81.7 to 90.0 |
| Urges to smoke | |||||||
| How often felt urges to smoke in previous 24 hours | |||||||
| No/few urges/don’t know | 707 | 83.2 | 80.5 to 85.5 | 82.0 | 78.7 to 85.3 | 78.7 | 74.8 to 82.6 |
| Frequent urges (a lot of the time-all of the time) | 135 | 15.9 | 13.6 to 18.5 | 18.0 | 14.7 to 21.3 | 21.3 | 17.4 to 25.2 |
| Strength of urges to smoke in previous 24 hours | |||||||
| No urges/slight-to-moderate urges/don’t know | 738 | 86.8 | 84.4 to 88.9 | 82.8 | 79.0 to 86.5 | 83.0 | 79.0 to 87.0 |
| Strong-to-extremely strong urges | 109 | 12.8 | 10.7 to 15.2 | 17.2 | 13.5 to 21.0 | 17.0 | 13.0 to 21.0 |
*Includes those who report smoking regularly and those who smoke occasionally (not every day).
†Quit attempts: at baseline, since finding out about the pregnancy; at follow-up 1, since completing previous survey; follow-up 2, since birth of baby.