Table 1 Characteristics of the study participants, i.e. 307 mother-infant pairs recruited in 1996-1999
Characteristic | N | Median (Range) |
Maternal age (years) | 307 | 28 (18–41) |
Maternal pre-pregnancy BMI (kg/m2) | 307 | 23 (18–44) |
Maternal weight gain during pregnancy (%)a | 304 | 22 (3.9–46) |
Gestational length (days)b | 138 | 280 (249–300) |
Birth weight of the child (g)b | 150 | 3510 (2430–5000) |
Age of infant at 3-weeks-sampling (days)b | 148 | 24 (17–38) |
Weight of the infant at 3 monthsc | 109 | 6180 (4350–8600) |
Age of infant at 3-months-sampling (days)c | 115 | 91 (75–123) |
Maternal serum TH concentrations, early pregnancy | Â | Â |
 TSH (mIU/L) | 220 | 1.3 (0.002–7.5) |
 Total T3 (nmol/L) | 219 | 2.4 (0.57–3.7) |
 Free T4 (pmol/L) | 220 | 11 (7.8–20) |
Maternal serum TH concentrations, late pregnancy | Â | Â |
 TSH (mIU/L) | 281 | 1.4 (0.06–6.7) |
 Total T3 (nmol/L) | 281 | 2.5 (1.1–3.8) |
 Free T4 (pmol/L) | 281 | 8.3 (5.7–13) |
 anti-TPOd (kIU/L) | 260 | 8.6 (5.5–134) |
Infant serum TH concentrations, 3Â weeks of age | Â | Â |
 TSH (mIU/L) | 148 | 2.4 (0.54–6.4) |
 Total T3 (nmol/L) | 145 | 2.8 (1.4–4.2) |
 Free T4 (pmol/L) | 150 | 17 (12–23) |
Infant serum TH concentrations, 3Â months of age | Â | Â |
 TSH (mIU/L) | 115 | 1.8 (0.77–4.8) |
 Total T3 (nmol/L) | 115 | 3.0 (1.7–4.2) |
 Free T4 (pmol/L) | 114 | 15 (10–22) |
| Â | N | % |
Country of birth | Â | Â |
 Nordic country | 291 | 95 |
 Non-Nordic country | 16 | 5 |
Years of education | Â | Â |
 ≤4 years of high school | 144 | 49 |
 1–3 years of higher education | 72 | 24 |
 >3 years of higher education | 79 | 27 |
Smoking habits during pregnancy (smoker/non-smoker) | 58/194 | 19/81 |
Alcohol during pregnancy (no/yes) | 254/52 | 83/17 |
Mode of delivery (vaginal/caesarean)b | 120/18 | 87/13 |
Sex of the child (male/female)b | 83/67 | 55/45 |