Table II.
The Infant Development and the Environment Study: characteristics of mothers and infants.
| Mothers (N = 753) | Categorical variables | N | (%) | ||
| Center | |||||
| San Francisco, CA | 187 | (24.83) | |||
| Minneapolis, MN | 202 | (26.83) | |||
| Rochester, NY | 212 | (28.15) | |||
| Seattle, WA | 152 | (20.19) | |||
| Race/Ethnicity | |||||
| White/Not Hispanic | 500 | (66.40) | |||
| Other | 253 | (33.60) | |||
| Smoking | |||||
| Yes | 43 | (5.81) | |||
| No | 697 | (94.19) | |||
| Education | |||||
| Less than college | 191 | (25.64) | |||
| Graduated college | 554 | (74.36) | |||
| Marital status | |||||
| Married/ Living as married | 622 | (83.16) | |||
| Separated/divorced/single | 126 | (16.84) | |||
| Continuous variables | Mean (SD) | Percentiles |
|||
| 25th | 50th | 75th | |||
| All Infants | Age | 31.09 (5.52) | 27.37 | 31.52 | 35.03 |
| Pre-pregnancy BMI (kg/m2) | 26.23 (6.29) | 21.81 | 24.55 | 29.21 | |
| Weight at exam (kg) | 3.37 (0.71) | 2.96 | 3.30 | 3.66 | |
| Gestational age (weeks) | 39.31 (1.79) | 38.71 | 39.57 | 40.57 | |
| Age at exam (days) | 6.44 (15.55) | 1 | 1 | 2 | |
| Weight-for-length z-score (ZWL) | −0.39 (1.26) | −1.09 | −0.34 | 0.36 | |
| Boys (N = 366) | AGDAS (mm) | 24.73 (4.55) | 21.73 | 24.33 | 27.17 |
| AGDAP (mm) | 49.66 (5.91) | 45.6 | 49.03 | 53.23 | |
| Penile width (mm) | 10.81 (1.32) | 9.93 | 10.78 | 11.5 | |
| Girls (N = 373) | AGDAF (mm) | 16.02 (3.22) | 13.9 | 15.73 | 18.20 |
| AGDAC (mm) | 36.60 (3.89) | 34.07 | 36.78 | 39.17 | |