Table 1.
Maternal and offspring characteristics for the NHBCS () and RICHS () samples.
| Maternal characteristics | NHBCSa | RICHSa |
|---|---|---|
| Smoking during pregnancy | ||
| Any | 21 (6.1%) | 19 (13.5%) |
| None | 322 (93.9%) | 122 (86.5%) |
| Educational attainment | ||
| High school or less | 37 (10.8%) | 34 (24.1%) |
| More than high school | 306 (89.2%) | 107 (75.9%) |
| Ethnicity | ||
| Not white | 6 (1.7%) | 36 (25.5%) |
| White | 337 (98.3%) | 105 (74.5%) |
| Infant characteristics | ||
| Gestational age (weeks) | 38.95 (1.54) | 39.33 (1.00) |
| Birth weight (g)b | 3435.14 (510.95) | 3623.09 (716.03) |
| Size for gestational ageb | ||
| SGA | 15 (4.4%) | 21 (14.9%) |
| AGA | 292 (86.1%) | 68 (48.2%) |
| LGA | 32 (9.4%) | 52 (36.9%) |
| Sex | ||
| Female | 159 (46.4%) | 68 (48.2%) |
| Male | 184 (53.6%) | 73 (51.8%) |
| Placental Cd (ng/g)c | ||
| Overall | 3.13 (2.61) | 4.37 (2.71) |
| Below cohort-specific median | 2.07 (1.05) | 2.78 (1.35) |
| Above cohort-specific median | 4.68 (2.32) | 5.49 (2.44) |
Note: AGA, adequate for gestational age; Cd, cadmium; LGA, large for gestational age; NHBCS, New Hampshire Birth Cohort Study; RICHS, Rhode Island Child Health Study; SGA, small for gestational age.
a
Means and standard deviations are presented for continuous variables, whereas frequencies and percentages are presented for categorical variables.
b
Four samples were missing for birth weight and SGA/AGA/LGA classifications in the NHBCS; all other continuous and categorical variables had no missing values.
c
Medians and interquartile ranges (IQRs) presented owing to skewed distributions of Cd concentrations.