Comparison of participants who completed all three questionnaires with those who completed either one or two questionnaires
| Characteristic | Completed all follow-up surveys, n=397 (46.7%) | Did not complete all surveys, n=453 (53.3%) | P value |
| n (%) | n (%) | ||
| Weeks’ gestation (mean, SD) | 15.8 (4.1) | 15.4 (4.1) | 0.14 |
| Age, years (mean, SD) | 26.5 (5.6) | 25.2 (5.5) | <0.001*** |
| Baseline smoking status | |||
| Current smoker | 199 (50.1) | 289 (63.8) | |
| Ex-smoker | 198 (49.9) | 164 (36.2) | <0.001*** |
| Previous pregnancy | |||
| Not been pregnant before | 143 (36.0) | 132 (29.1) | |
| Been pregnant before | 250 (63.0) | 314 (69.3) | 0.037* |
| Partner smoking | |||
| Partner is not a current smoker/no partner | 158 (39.8) | 187 (41.3) | |
| Partner is a current smoker | 236 (59.4) | 263 (58.2) | 0.67 |
| Current smokers only | |||
| Reported quit attempt since learning of pregnancy/previous questionnaire/birth of baby† | |||
| Yes | 115 (57.8) | 157 (54.3) | |
| No | 78 (39.2) | 122 (42.2) | 0.47 |
| Heaviness of Smoking Index | |||
| Low dependence (0–2) | 140 (70.4) | 170 (58.8) | |
| Moderate dependence (3–4) | 46 (23.1) | 100 (34.6) | |
| High dependence (5–6) | 1 (0.5) | 7 (2.4) | 0.004* |
*Significant at <0.05.
***Significant at <0.001.
†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.