TABLE 1.
Participant baseline characteristics; n (%) or mean (SD).
| Characteristic | Provided saliva samples at baseline and at follow‐up (n = 20) | Failed to provide saliva samples at baseline and at follow‐up (n = 20) |
|---|---|---|
| Age (years) | 29.05 (4.89) | 29.25 (5.53) |
| Ethnicity | ||
| White | 20 (100%) | 18 (90%) |
| Qualifications d | ||
| None | 1 (5%) | 4 (20%) |
| GCSEs | 13 (65%) | 6 (30%) |
| A‐levels | 6 (30%) | 6 (30%) |
| Degree | 0 (0%) | 4 (20%) |
| Gestation (days) | 110.5 (38.28) | 99.3 (28.28) |
| Partner who smokes | ||
| No partner | 2 (10%) | 4 (20%) |
| Partner who smokes | 14 (70%) | 11 (55%) |
| Partner is a non/ex‐smoker | 4 (20%) | 5 (25%) |
| Smoking status in previous pregnancies | ||
| No previous pregnancies | 1 (5%) | 2 (10%) |
| Yes | 16 (80%) | 17 (85%) |
| No | 3 (15%) | 1 (5%) |
| Number of hours after waking before first cigarette | ||
| Within 5 minutes | 5 (25%) | 6 (30%) |
| 6–30 minutes | 10 (50%) | 10 (50%) |
| 31–59 minutes | 2 (10%) | 2 (10%) |
| 1–2 hours | 2 (10%) | 2 (10%) |
| More than 2 hours | 1 (5%) | 0 (0%) |
| E‐cigarette use | 1 (5%) | 1 (5%) |
| Number of cigarettes smoked per day c | 8 (3.63) | 11 (6.58) |
| Saliva cotinine concentration (ng/ml) | 156.54 (69.13) | 164 (103.87) |
| Exhaled carbon monoxide concentration (p.p.m.) | 14 (7.24) a | 23.67 (11.14) b |
a
n = 17;
b
n = 12.
c
Data have been rounded to the nearest cigarette;
d
GCSEs (General Certificate of Secondary Education) are sat at age 16; A (Advanced) levels are sat at age 18 and degree refers to any undergraduate degree certificate.