Table 1.
General characteristics of pregnant women and their babies
| Characteristics | n | Mean ± S.D. or n (%) |
|---|---|---|
| Pregnant women | ||
| Age, yrs | 959 | 30.1 ± 3.5 |
| Pre-pregnancy weight, kg | 950 | 55.4 ± 8.9 |
| Pre-pregnancy BMI, kg/m2 | 943 | 21.3 ± 3.2 |
| Residential area | 960 | |
| Seoul | 223 (23.2) | |
| Cheonan | 298 (31.1) | |
| Ulsan | 439 (45.7) | |
| Family income, US$/month | 925 | |
| <2000 | 250 (27.0) | |
| 2000-4000 | 512 (55.4) | |
| >4000 | 163 (17.6) | |
| Education | 941 | |
| ≤High school | 265 (28.1) | |
| ≤University | 186 (19.8) | |
| ≥Graduate school | 491 (52.2) | |
| Nutritional supplements, yes | 960 | 410 (42.7) |
| Secondhand smokers, yes | 898 | 772 (86.0) |
| Urinary cotinine levels, μ mol/mol creatinine | 905 | 17.4 ± 152.1 |
| Babies | ||
| Gestational age, d | 939 | 274.9 ± 10.1 |
| Birth length, cm | 920 | 50.5 ± 2.5 |
| Birth weight, g | 959 | 3268.6 ± 424.7 |
| Gender, girls | 955 | 458 (48.0) |
| Umbilical cord blood mercury, μ g/L | 746 | 5.9 ± 3.7 |
| Breastfeeding status, yes | 860 | 559 (65.0) |
| BSID-II | 960 | |
| MDI | 96.2 ± 11.9 | |
| PDI | 96.0 ± 14.7 | |
S.D. standard deviation BSID-II Bayley Scales of Infant Development II MDI mental development index PDI psychomotor development index