Table 1 Demographic characteristics of Chemicals in Our Body (CIOB) study population (N = 506)
| Â | N (%) |
Maternal Age | |
 Mean (SD) | 32 (5.4) |
Maternal Race/Ethnicity | |
 Non-Hispanic White | 193 (38%) |
 Non-Hispanic Black | 40 (8%) |
 Hispanic | 173 (34%) |
 Asian/Pacific Islander | 95 (19%) |
 Missing | 5 (1%) |
Pre-pregnancy Body Mass Index | |
 Underweight (< 18.5 kg/m2) | 12 (2%) |
 Normal (18.5–24.9 kg/m2) | 236 (47%) |
 Overweight (25–29.9 kg/m2) | 128 (25%) |
 Obese (≥  30 kg/m2) | 89 (18%) |
 Missing | 41 (8%) |
Infant Sex | |
 Female | 257 (51%) |
 Missing | 27 (5.3%) |
Parity | |
 One or More Previous Births | 254 (50%) |
 Missing | 7 (1%) |
Maternal Education | |
  < High School | 59 (12%) |
 High School Graduate or Some College | 139 (27%) |
 College Degree | 116 (23%) |
 Graduate Level Degree | 185 (37%) |
 Missing | 7 (1%) |
Smoking Status | |
 Never | 421 (83%) |
 Ever | 60 (12%) |
 Current | 10 (2%) |
 Missing | 15 (3%) |
Difficulty Paying for Basics | |
 Yes | 146 (29%) |
 Missing | 12 (2%) |
Food Insecurity | |
 Yes | 79 (16%) |
Foreign Born | |
 Yes | 209 (41%) |
 Missing | 75 (15%) |
Preterm Birth | |
  < 37 weeks gestation | 41 (8%) |
 Missing | 13 (3%) |
| Â | Median (SD) |
Birth Weight (grams) | 3300 (580) |
 Missing | 18 (4%) |
Gestational Age at Delivery (weeks) | 39 (2.0) |
 Missing | 13 (3%) |