Table 1 Clinical characteristics for Total biomarker study group (n = 2603) and Nicotine exposure study group (n = 2278)
Maternal and pregnancy characteristics | Total biomarker study group (n = 2603) | Nicotine exposure study group (n = 2278) | ||
|---|---|---|---|---|
N | % | N | % | |
Fetal sex | ||||
Male | 1371 | 53.0 | 1201 | 53.0 |
Female | 1214 | 47.0 | 1066 | 47.0 |
Gestational age at blood sampling (weeks)*, mean ± SD | 19.8 ± 6.2 | 19.8 ± 6.1 | ||
16–17 | 199 | 7.7 | 168 | 7.5 |
18 | 811 | 31.5 | 695 | 30.8 |
19–20 | 993 | 38.6 | 859 | 38.1 |
21–23 | 573 | 22.2 | 532 | 23.6 |
Maternal age at enrollment (years), mean ± SD | 32.3 ± 4.2 | 32.4 ± 4.2 | ||
< 30 | 900 | 34.5 | 770 | 33.8 |
30–35 | 1120 | 43.0 | 993 | 43.6 |
> 35–40 | 500 | 19.2 | 441 | 19.4 |
> 40 | 83 | 3.2 | 74 | 3.2 |
Maternal prepregnancy body mass index (kg/m2), mean ± SD | 24.8 ± 3.7 | 24.8 ± 3.7 | ||
Underweight < 18.5 | 87 | 3.4 | 76 | 3.4 |
Normal weight 18.5–24.9 | 1902 | 74.9 | 1669 | 75.1 |
Overweight 25.0–29.9 | 405 | 16.0 | 361 | 16.3 |
Obese ≥ 30.0 | 145 | 5.7 | 115 | 5.2 |
Parity (previous deliveries) | ||||
0 | 1694 | 65.1 | 1369 | 60.1 |
1 | 717 | 27.5 | 717 | 31.5 |
> 1 | 192 | 7.4 | 192 | 8.4 |
Country of origin | ||||
Norway or Sweden | 2020 | 77.6 | 2020 | 88.7 |
Rest of the world | 258 | 9.9 | 258 | 11.3 |
Education (years) | ||||
Preliminary school only (9–10 years) | 18 | 0.7 | 18 | 0.8 |
High school only | 230 | 8.8 | 230 | 10.1 |
Higher education < 4 years | 730 | 28.0 | 730 | 32.2 |
Higher education ≥ 4 years | 1289 | 49.5 | 1289 | 56.8 |
Other | 2 | 0.1 | 2 | 0.1 |
Snus | ||||
Never | 1762 | 67.7 | 1762 | 77.3 |
Stopped before pregnancy | 343 | 13.2 | 343 | 15.1 |
Stopped when recognizing pregnancy | 160 | 6.2 | 160 | 7.0 |
Current | 13 | 0.5 | 13 | 0.6 |
Smoking | ||||
Never | 1762 | 67.7 | 1762 | 77.3 |
Stopped before pregnancy | 404 | 15.5 | 404 | 17.6 |
Stopped when recognizing pregnancy | 97 | 3.7 | 97 | 4.3 |
Current | 15 | 0.6 | 15 | 0.7 |