Characteristics of singleton infants greater than 200 g and between 22 and 45 gestational weeks born in Massachusetts in 1990
| Study population | Preterm | SGA* | LBW* | Mean birth weight (g)* | |
|---|---|---|---|---|---|
| Abbreviations: SGA, small for gestational age; LBW, low birth weight. | |||||
| *Term births only. | |||||
| Total births | 56513 | 3173 | 5310 | 1325 | 3458 |
| Maternal race | |||||
| Caucasian | 42047 (74.4%) | 5.0% | 9.2% | 2.2% | 3503 |
| African-American | 6025 (10.7%) | 11.6% | 9.2% | 4.9% | 3310 |
| Other | 5907 (10.5%) | 8.6% | 13.6% | 3.2% | 3359 |
| Asian | 2428 (4.3%) | 9.0% | 17.3% | 4.0% | 3263 |
| American Indian | 106 (0.2%) | 8.9% | 16.3% | 5.8% | 3336 |
| Maternal age (y) | |||||
| 11–22 | 11024 (19.5%) | 8.7% | 14.0% | 3.7% | 3346 |
| 23–34 | 38456 (68.1%) | 5.5% | 9.1% | 2.4% | 3482 |
| 35–45 | 7033 (12.4%) | 6.4% | 8.7% | 2.8% | 3504 |
| Maternal education | |||||
| 9th grade or less | 5192 (9.2%) | 9.8% | 16.2% | 4.7% | 3324 |
| 10th or 11th grade | 5947 (10.5%) | 10.1% | 14.7% | 4.5% | 3333 |
| High school graduate | 18752 (33.2%) | 6.5% | 10.6% | 3.0% | 3443 |
| At least 1 year of college | 26622 (47.1%) | 4.6% | 7.4% | 1.8% | 3521 |
| Maternal smoking | |||||
| 0 cigarettes/day | 44986 (79.6%) | 5.7% | 8.1% | 2.0% | 3502 |
| 1–5 cigarettes/day | 2404 (4.3%) | 8.2% | 13.9% | 4.8% | 3338 |
| 6–10 cigarettes/day | 4409 (7.8%) | 8.4% | 17.2% | 5.6% | 3287 |
| 11 or more cigarettes/day | 4714 (8.3%) | 8.6% | 19.7% | 6.1% | 3259 |
| Prenatal care (Kessner Index) | |||||
| No prenatal care | 320 (0.6%) | 31.8% | 28.0% | 14.9% | 3117 |
| Inadequate | 2115 (3.7%) | 13.4% | 15.6% | 5.6% | 3300 |
| Intermediate | 10142 (18.0%) | 9.0% | 12.8% | 3.9% | 3378 |
| Adequate | 43936 (77.7%) | 5.1% | 9.7% | 2.2% | 3485 |
| Number of previous births | |||||
| 0 | 25029 (44.3%) | 6.4% | 11.7% | 3.1% | 3414 |
| 1 | 17915 (31.7%) | 5.2% | 8.2% | 2.1% | 3498 |
| 2 or 3 | 11764 (20.8%) | 6.5% | 8.8% | 2.5% | 3493 |
| 4 or more | 1774 (3.1%) | 11.6% | 11.2% | 4.1% | 3454 |
| Infant gender | |||||
| Male | 28904 (51.2%) | 5.9% | 10.0% | 2.2% | 3524 |
| Female | 27609 (48.9%) | 6.5% | 10.0% | 3.2% | 3390 |
| Average TTHM (μg/l) during pregnancy | |||||
| 0–60 | 44232 (78.3%) | 6.2% | 9.7% | 2.7% | 3463 |
| >60–80 | 7588 (13.4%) | 6.1% | 10.2% | 2.5% | 3458 |
| >80 | 4693 (8.3%) | 6.2% | 12.0% | 2.9% | 3416 |