Table 2.
Baseline characteristics of study subjects (n = 417)
| Variable | Trimester |
p valuea | ||
|---|---|---|---|---|
| First | Second | Third | ||
| No. of subjects | 135 | 143 | 139 | |
| Age, yr | 32 ± 3 | 33 ± 4 | 33 ± 3 | 0.020 |
| Weight, kg | 55 ± 8 | 60 ± 7 | 65 ± 8 | < 0.001 |
| TSH, mIU/L | 1.32 (0.01–9.43) | 1.62 (0.01–7.40) | 1.59 (0.15–7.54) | 0.280 |
| f T4, ng/dL | 1.14 (0.77–2.22) | 0.91 (0.64–1.64) | 0.88 (0.54–1.20) | < 0.001 |
| UIC, µg/Lb | 439 (20–5,020) | 397 (29–10,192) | 451 (19–5,431) | 0.480 |
Values are presented as mean ± SD or median (range).
TSH, thyroid stimulating hormone; fT4, free thyroxine; UIC, urinary iodine concentration.
a
One-way analysis of variance or Kruskall-Wallis test was used for the comparison of variables from each trimester.
b
Urine samples were collected from 275 subjects: 65 samples in the first trimester, 108 in the second trimester, and 102 in the third trimester.