Table 1.
Participant Characteristics (% a), National Birth Defects Prevention Study, 2006–2011 (n = 4395)
| Characteristic | Low Stress Score (0–3)b | High Stress Score (4–7)b |
|---|---|---|
| N = 4186 | N = 209 | |
| Race/ethnicity | ||
| White non-Hispanic | 2351 (56.2) | 96 (45.9) |
| Black non-Hispanic | 404 (9.7) | 43 (20.6) |
| Hispanic | 1131 (27.0) | 48 (23.0) |
| Other | 299 (7.1) | 22 (10.5) |
| Missing | 1 (< 0.1) | – |
| Age (years) | ||
| < 20 | 351 (8.4) | 30 (14.4) |
| 20–24 | 876 (20.9) | 88 (42.1) |
| 25–29 | 1247 (29.8) | 45 (21.5) |
| 30–34 | 1112 (26.6) | 31 (14.8) |
| > 34 | 600 (14.3) | 15 (7.2) |
| Parity | ||
| Nulliparous | 1656 (39.6) | 89 (42.6) |
| Parous | 2529 (60.4) | 120 (57.4) |
| Missing | 1 (< 0.1) | – |
| Education | ||
| < High school | 658 (15.7) | 32 (15.3) |
| High school graduate | 917 (21.9) | 81 (38.8) |
| > High school | 2602 (62.2) | 96 (45.9) |
| Missing | 9 (0.2) | – |
| Smokingc | ||
| No | 3559 (85.0) | 108 (51.7) |
| Yes | 625 (14.9) | 101 (48.3) |
| Missing | 2 (< 0.1) | – |
| Use of folic acid-containing vitamin/mineral supplement | ||
| Began month before or 1st month | 2423 (57.9) | 86 (41.2) |
| Began 2nd - 3rd month | 1277 (30.5) | 79 (37.8) |
| Began later or none | 447 (10.7) | 41 (19.6) |
| Missing | 39 (0.9) | 3 (1.4) |
| Alcohol use c | ||
| None | 2611 (62.4) | 103 (49.3) |
| Some | 1029 (24.6) | 48 (23.0) |
| Binge drinking d | 511 (12.2) | 57 (27.3) |
| Missing | 35 (0.8) | 1 (0.5) |
| Pre-pregnancy body mass index (kg/m2) | ||
| Underweight (< 18.5) | 200 (4.8) | 10 (4.8) |
| Normal weight (18.5–24.9) | 2041 (48.8) | 91 (43.5) |
| Overweight (25.0–29.9) | 925 (22.1) | 48 (23.0) |
| Obese (> = 30.0) | 849 (20.3) | 55 (26.3) |
| Missing | 171 (4.1) | 5 (2.4) |
a Numbers may not add to 100% due to rounding
b Indices reflect the number of questions that had a “yes” response
c From one month before through three months after conception
d Having four or more drinks on at least one occasion