Table 1.
Characteristics of the mothers and infants (n = 133).
| Characteristic | N (%) | |
|---|---|---|
| Maternal age | Mean (SD), min–max | 31.4 (4.6) 20–42 |
| Marital status | Single | 1 (1) |
| Cohabiting | 82 (61.2) | |
| Married | 48 (35.8) | |
| In a relationship | 2 (2) | |
| Country of origin | Norway | 120 (90) |
| Other (11 different countries) | 13 (10) | |
| Pre pregnancy, BMI, kg/m2 | < 18.5 | 4 (3) |
| 18.5–24.9 | 93 (70) | |
| 25–30 | 21 (16) | |
| > 30 | 15 (11) | |
| BMI by inclusion, kg/m2 | < 18.5 | 4 (3) |
| 18.5–24.9 | 83 (62) | |
| 25–30 | 30 (23) | |
| > 30 | 16 (12) | |
| Planning new pregnancy | Yes | 54 (41) |
| Pregnant now | Yes | 2 (2) |
| Infants age, in months 1 | 1–4 | 54 (41) |
| 5–7 months | 27 (20) | |
| 8–11 months | 35 (26) | |
| 12–13 months | 17 (13) | |
| Educational level | <12 years | 6 (5) |
| 12 years | 19 (15) | |
| 1–4 years college/university | 52 (39) | |
| >4 years college/university | 56 (42) | |
| Smoking status | Never smoked | 103 (77) |
| Smoked before pregnancy | 27 (20) | |
| Occasionally during pregnancy | 0 | |
| Daily smoker during pregnancy 2 | 3 (2) | |
| Dietary supplement use | Any supplement (FFQ) | 76 (57) |
| Iodine-containing supplement past 24-h | 30 (23) | |
| Adhering to a vegetarian or vegan diet | 6 (4) | |
| Diet includes dairy | No | 9 (7) |
| Occasionally | 22 (16) | |
| Yes, daily | 103 (77) | |
| Self-reported hypothyroidism, no use of thyroid medication | 2 (2) | |
1 Seven children in the 13 months category were 13 months, plus 1 or 2 weeks (recruited at age 12 months); 2 number of cigarettes daily: 12 ± 3 during the whole gestation. BMI, Body Mass Index.3.2. Iodine Concentrations in Human Milk (HMIC) and Urine (UIC).