Table 2.
Spontaneous and Medically Induced Preterm Birth Rates (%) in 1989 and 2004 for various demographic groups from the National Center for Health Statistics Natality Files
| Spontaneous 1989 | Spontaneous 2004 | Induced 1989 | Induced 2004 | |
|---|---|---|---|---|
| All Births | 7.8 | 6.2 | 3.4 | 6.6 |
| Maternal Race/Ethnicity | ||||
| White N-H | 5.9 | 5.3 | 3.1 | 6.6 |
| Black N-H | 15.2 | 9.4 | 4.9 | 8.9 |
| Hispanic | 8.6 | 6.7 | 3.1 | 5.7 |
| Asian & Pacific Islander | 7.7 | 5.7 | 2.7 | 5.1 |
| Native American | 9.8 | 7.7 | 3.0 | 6.7 |
| Maternal Age in Years | ||||
| < 15 | 21.4 | 16.2 | 4.4 | 7.8 |
| 15-19 | 12.4 | 9.3 | 3.3 | 5.6 |
| 20-24 | 8.7 | 7.0 | 3.1 | 5.8 |
| 25-29 | 6.6 | 5.7 | 3.1 | 6.1 |
| 30-34 | 6.2 | 5.2 | 3.6 | 7.1 |
| 35-39 | 6.7 | 5.2 | 4.4 | 8.6 |
| 40-45 | 7.4 | 5.5 | 5.6 | 10.9 |
| 45-49 | 8.6 | 5.6 | 7.0 | 20.7 |
| Pregnancy Plurality | ||||
| Singleton | 7.5 | 5.9 | 2.8 | 5.2 |
| Twin | 23.0 | 14.7 | 24.7 | 45.4 |
| Triplet+ |
17.3 | 4.9 | 69.3 | 88.5 |