Table 2.
Concentration of the thyroid hormones FT4, FT3, and TSH in maternal blood and cord blood of 378 mother-neonate pairs and by tertiles of placental iodine concentration
| Thyroid hormone | Total (n = 378) | Tertile 1 (n = 122) | Tertile 2 (n = 125) | Tertile 3 (n = 131) | p value for trend |
|---|---|---|---|---|---|
| Mother | |||||
| FT4, pmol/L | 12.1 (2.0) | 11.4 (1.9) | 12.0 (2.0) | 12.7 (1.8) | 0.0001 |
| FT3, pmol/L | 4.0 (1.0) | 4.1 (0.9) | 3.9 (1.0) | 4.1 (1.2) | 0.25 |
| TSH, mIU/L | 2.4 (1.3) | 2.5 (1.2) | 2.3 (1.4) | 2.4 (1.3) | 0.49 |
| Neonate | |||||
| FT4, pmol/L | 16.5 (2.0) | 15.9 (2.2) | 16.5 (1.9) | 17.0 (1.9) | 0.0001 |
| FT3, pmol/L | 2.3 (0.6) | 2.3 (0.5) | 2.4 (0.6) | 2.4 (0.6) | 0.36 |
| TSH, mIU/L | 10.7 (7.6) | 10.5 (7.0) | 11.2 (8.6) | 10.4 (7.3) | 0.67 |
| Placental iodine concentrations, µg/kg | 26.2 (4.3) | 21.6 (2.0) | 25.8 (1.0) | 30.9 (2.8) | – |
Data are presented as mean (SD). Tertiles are based on the placental iodine concentration: I ≤ 24.2; 24.2 < I ≤ 27.5; and I > 27.5