Table 1.
Maternal characteristics by race in the Collaborative Perinatal Project, 1959-1966
| Characteristics | White | Black | P |
|---|---|---|---|
| N | 17,662 | 14,633 | |
| Maternal age (year) | < 0.0001 | ||
| < 20 | 2,960 (16.8) | 4,026 (27.5) | |
| 20-25 | 6,866 (38.9) | 4,848 (33.1) | |
| 25-30 | 4,152 (23.5) | 2,894 (19.8) | |
| 30-35 | 2,233 (12.6) | 1,710 (11.7) | |
| ≥ 35 | 1,451 (8.2) | 1,155 (7.9) | |
| Married | 15,722 (89.0) | 9,261 (63.3) | < 0.0001 |
| Maternal education levels (year) | < 0.0001 | ||
| Less than high school (≤ 9) | 4,133 (23.4) | 4,076 (27.9) | |
| High school (10-12) | 10,071 (57.0) | 9,852 (67.3) | |
| College and above (> 12) | 3,458 (19.6) | 705 (4.8) | |
| Socioeconomic status | < 0.0001 | ||
| 1 (Lowest) | 492 (2.8) | 1,436 (9.8) | |
| 2 | 3,351 (19.0) | 5,607 (38.3) | |
| 3 | 5,231 (29.6) | 5,089 (34.8) | |
| 4 | 5,109 (28.9) | 2,128 (14.5) | |
| 5 (Highest) | 3,479 (19.7) | 373 (2.6) | |
| Parity | < 0.0001 | ||
| 0 | 5,548 (31.4) | 3,968 (27.1) | |
| 1 | 4,492 (25.4) | 3,049 (20.8) | |
| ≥ 2 | 7,622 (43.2) | 7,616 (52.1) | |
| Smoking during pregnancy | 9,551 (54.1) | 6,660 (45.5) | < 0.0001 |
| Maternal pre-pregnancy BMI (kg/m2) | < 0.0001 | ||
| < 18.5 | 3,597 (20.4) | 1,624 (11.1) | |
| 18.5-25 | 11,142 (63.1) | 9,003 (61.5) | |
| 25-30 | 1,999 (11.3) | 2,600 (17.8) | |
| ≥ 30 | 924 (5.2) | 1,406 (9.6) | |
| Stillbirth | 149 (0.8) | 150 (1.0) | < 0.0001 |
| Birth weight (g) | < 0.0001 | ||
| < 2500 | 1,183 (6.7) | 1,694 (11.6) | |
| 2500-2999 | 3,563 (20.2) | 4,380 (29.9) | |
| 3000-3499 | 7,096 (40.2) | 5,814 (39.7) | |
| 3500-3999 | 4,534 (25.7) | 2,279 (15.6) | |
| ≥ 4000 | 1,286 (7.3) | 466 (3.2) | |
| Gestational age (week) | < 0.0001 | ||
| 32-36 | 1,505 (8.5) | 2,564 (17.5) | |
| 37-41 | 13,787 (78.1) | 10,538 (72.0) | |
| 42-44 | 2,370 (13.4) | 1,531 (10.5) | |
| Small for gestational age | 1,575 (10.3) | 1,381 (10.5) | 0.5076 |
| Pregnancy associated hypertension | 3,445 (19.6) | 3,443 (23.6) | < 0.0001 |
| Chronic hypertension | 1,136 (6.4) | 1,573 (10.8) | 0.0002 |
| Gestational diabetes | 221 (1.3) | 119 (0.8) | 0.0002 |
| Pre-pregnancy diabetes | 400 (2.3) | 149 (1.0) | < 0.0001 |