Characteristics of 30–346/7 week gestation premature infants in the study
| Entire sample* | Range across sites† | |
|---|---|---|
| *Results are weighted on the basis of different sampling fractions. | ||
| †Unweighted data. | ||
| ‡14% of all respondents did not provide income information. | ||
| SGA, Small for gestational age; SNAP-II, score for neonatal acute physiology, version II; nCPAP, nasal continuous positive airways pressure; IMV, intermittent ventilation; PMAD, premenstrual age at discharge. | ||
| Enrolled births | 1250 | 60–100 |
| Maternal characteristics | ||
| Mean age (years) | 31.1 | 28.6–33.8 |
| Completed high school (%) | 73.3 | 56.7–86.0 |
| Annual income <$30 000 (%)‡ | 12.5 | 1.1–29.2 |
| Annual income $30 000–49 999 (%)‡ | 12.0 | 3.9–24.7 |
| Annual income ⩾$50 000 (%)‡ | 60.0 | 44.1–80.9 |
| White (%) | 58.5 | 26.0–86.1 |
| African-American (%) | 14.2 | 0.0–35.1 |
| Asian (%) | 13.4 | 3.5–31.3 |
| Hispanic (%) | 10.3 | 0.0–26.5 |
| Antenatal steroids | ||
| All gestations | 66.0 | 61.5–72.0 |
| 30 weeks | 88.3 | 50.0–100 |
| 31 weeks | 84.8 | 70.0–100 |
| 32 weeks | 80.4 | 73.9–95.0 |
| 33 weeks | 73.1 | 54.2–85.7 |
| 34 weeks | 44.7 | 23.3–59.1 |
| Infant characteristics | ||
| Sex (% male) | 50.3 | 43.3–58.5 |
| Mean gestational age (weeks) | 33.1 | 32.9–33.5 |
| 33–346/7 weeks (%) | 61.9 | 53.0–76.7 |
| 30–326/7 weeks (%) | 38.1 | 23.3–47.0 |
| SGA (%) | 6.6 | 3.0–15.4 |
| Multiple gestation (%) | 39.5 | 20.0–51.0 |
| Mean birth weight (g) | 1933 | 1807–2091 |
| ⩾2000 g birth weight (%) | 41.5 | 30.0–56.7 |
| 1500–1999 g (%) | 43.3 | 31.7–50.0 |
| <1500 g (%) | 15.2 | 5.0–24.6 |
| Mean SNAP-II | 5.6 | 3.5–7.1 |
| Ever ventilated (%) | 45.7 | 18.3–59.0 |
| nCPAP only (%) | 19.1 | 8.0–31.0 |
| IMV without nCPAP (%) | 4.1 | 0.0–9.0 |
| Ever transported (%) | 14.4 | 0.0–58.3 |
| Received surfactant (%) | 24.6 | 6.7–29.0 |
| Mean PMAD (weeks) | 36.2 | 35.5–36.6 |