Table 1 Characteristics of subjects of this study
From: Serum levels of hydroxylated PCBs, PCBs and thyroid hormone measures of Japanese pregnant women
|  | n | Mean ± SD |
|---|---|---|
Age (years) | 127 | 33.8 ± 5.0 |
Pre-pregnancy body weight (kg) | 128 | 52.0 ± 6.6 |
Height (cm) | 128 | 159.2 ± 4.9 |
Parity (number of subjects) | 128 | Â |
 0 | 62 |  |
 ≥1 | 66 |  |
Smoking during pregnancy (number of subjects) | 127 | Â |
 No | 124 |  |
 Yes | 3 |  |
Smoked until becoming pregnant (number of subjects) | 124 | Â |
 No | 108 |  |
 Yes | 16 |  |