Table 1.
Sample characteristics.
| N | Mean | SD | Range | |
|---|---|---|---|---|
| Infant characteristics | ||||
| Gestational age, weeksa | 320 | 37.99 | 1.86 | 28–41 |
| Birthweight, grams | 320 | 3165.85 | 572.16 | 1310–4627 |
| Sex assigned at birth, % (n) | 320 | |||
| Female | – | 44 (140) | – | – |
| Male | – | 56 (180) | – | – |
| Race, % (n)b | 320 | |||
| Black/African American | – | 61.6 (197) | – | – |
| White/Caucasian | – | 23.9 (118) | – | – |
| Asian | – | 1.9 (6) | – | – |
| Native Hawaiian/Pacific Islander | – | 0.3 (1) | – | – |
| Other (not defined) | – | 0.6 (2) | – | – |
| Ethnicity, % (n) | 320 | |||
| Hispanic or Latino/a | – | 2.5 (8) | – | – |
| Not Hispanic or Latino/a | – | 96.9 (310) | – | – |
| Unspecified | – | 0.6 (2) | – | – |
| Postmenstrual age at MRI scan, weeks | 320 | 41.2 | 1.47 | 37-45 |
| Maternal characteristics | ||||
|---|---|---|---|---|
| Age at delivery, years | 320 | 29.27 | 5.29 | 19–42 |
| Tobacco use during pregnancy, % (n) | 320 | 11.6 (37) | – | – |
| Cannabis use during pregnancy and/or positive urine drug screen, % (n) | 320 | 10.9 (35) | – | – |
| Income-to-needs ratio | 311 | 2.80 | 2.97 | 0.32–12.48 |
| Family SES group | 311 | |||
| Lower, % (n) | – | 63 (196) | – | – |
| Higher, % (n) | – | 37 (115) | – | – |
All trimester-specific effects are included in the Supplementary Information material (Tables S4 and S5).
aPremature neonates included: n = 45 (3 very preterm [<32 weeks’ GA]; 4 moderate preterm [32–33 weeks’ GA]; 38 late preterm [34–36 weeks’ GA]).
bMore than one race reported for four infants (African American-Caucasian = 2; Caucasian-Asian = 2).