Table 1 Basal characteristics and exposure levels in 489 mother-baby pairs
|  | Male newborns (n = 252) | Female newborns (n = 237) | p valuea |
|---|---|---|---|
|  | Mean ± SD or median and the 5–95 percentiles (or number and %) in parenthesis | Mean ± SD or median and the 5–95 percentiles (or number and %) in parenthesis | |
Maternal characteristics | |||
 Maternal age (years) | 31.5 ± 4.3 | 31.3 ± 4.4 | 0.497 |
 Body weight before pregnancy (kg) | 53.1 ± 7.4 | 52.6 ± 8.4 | 0.511 |
 Body mass index before pregnancy (kg/m2) | 21.0 ± 2.4 | 20.9 ± 3.3 | 0.906 |
 Body weight gain during pregnancy (kg) | 9.6 ± 3.7 | 9.8 ± 3.6 | 0.584 |
 Fish/seafood intake during pregnancy (g/day) | 51.6 (13.1–109.2) | 53.6 (12.2–131.4) | 0.201 |
 Smoking habit during pregnancy (smokers, %) | 17 (6.7) | 20 (8.4) | 0.499 |
 Drinking habit during pregnancy (drinkers, %) | 82 (32.5) | 73 (30.8) | 0.698 |
 Delivery type (spontaneous, %) | 176 (69.8) | 178 (75.1) | 0.225 |
Newborn characteristics | |||
 Gestational age (weeks) | 39.5 ± 1.3 | 39.6 ± 1.2 | 0.516 |
 Birth weight (g) | 3126 ± 353 | 3036 ± 314 | 0.003 |
 Parity (first-born children, %) | 133 (52.8) | 123 (51.9) | 0.857 |
Biomarkers in cord blood | |||
 Total PCBs (ng/g-lipid)b | 49.4 (16.3–118.6) | 44.6 (19.6–107.5) | 0.170 |
 PCB-153 (ng/g-lipid)b | 10.6 (3.2–27.9) | 9.7 (3.9–23.4) | 0.243 |
 Total mercury (ng/g) | 10.2 (4.5–23.8) | 9.9 (4.0–21.4) | 0.669 |
 Lead (μg/dL) | 1.0 (0.6–1.7) | 1.0 (0.5–1.7) | 0.252 |