Table 1.
Demographics and clinical metrics of the study population overall and among births with adverse birth outcomes
| All births (n= 457 642) | LBW (n = 30 458) | SGA (n = 42 663) | PTB (n = 40 746) | |
|---|---|---|---|---|
| Mean BWT in g (SD) |
3320.8 (573.7) |
2003.1 (508.0) |
2534.1 (387.2) |
2392.6 (717.0) |
| Gestational age (%) |
|
|
|
|
| 24-34 weeks |
3.3 |
43.3 |
4.3 |
37.2 |
| 35-36 weeks |
5.6 |
25.0 |
7.6 |
62.8 |
| 37-42 weeks |
91.1 |
31.7 |
88.0 |
N/A |
| Infant sex male (%) |
51.2 |
46.9 |
50.3 |
53.2 |
| First born (%) |
42.7 |
50.9 |
52.5 |
45.7 |
| Trimester prenatal care began (%) |
|
|
|
|
| First |
84.9 |
81.0 |
79.6 |
83.2 |
| Second |
12.6 |
15.0 |
16.7 |
12.4 |
| Third |
1.9 |
1.9 |
2.6 |
2.1 |
| None |
0.6 |
2.1 |
1.1 |
2.3 |
| Year of birth (%) |
|
|
|
|
| 2002 |
19.2 |
19.1 |
19.0 |
19.0 |
| 2003 |
19.3 |
19.4 |
19.3 |
19.5 |
| 2004 |
19.9 |
19.5 |
19.2 |
20.0 |
| 2005 |
20.4 |
20.5 |
20.6 |
20.5 |
| 2006 |
21.1 |
21.5 |
22.0 |
20.9 |
| Race/ethnicity (%) |
|
|
|
|
| Non-hispanic white |
62.4 |
39.0 |
48.2 |
57.5 |
| Non-hispanic black |
22.8 |
50.2 |
37.7 |
31.2 |
| Hispanic |
14.8 |
10.8 |
14.1 |
11.3 |
| Maternal education (%) |
|
|
|
|
| <9 years |
6.2 |
5.6 |
6.8 |
5.3 |
| 9-11 years |
15.0 |
21.2 |
22.5 |
17.4 |
| 12 years |
28.4 |
33.1 |
33.3 |
30.7 |
| 13-15 years |
22.4 |
21.6 |
20.0 |
23.5 |
| >15 years |
28.1 |
18.5 |
17.4 |
23.1 |
| Maternal age (%) |
|
|
|
|
| 15-19 years |
11.4 |
16.4 |
17.8 |
13.5 |
| 20-24 years |
27.2 |
30.4 |
33.0 |
27.6 |
| 25-29 years |
27.2 |
23.8 |
23.7 |
25.3 |
| 30-34 years |
22.7 |
18.3 |
16.4 |
21.0 |
| 35-39 years |
9.9 |
9.1 |
7.6 |
10.5 |
| 40-44 years |
1.7 |
2.0 |
1.6 |
2.2 |
| Tobacco use (%) |
11.7 |
21.0 |
22.2 |
15.5 |
| Married (%) |
64.4 |
49.7 |
48.1 |
58.1 |
| Household median income ($) |
|
|
|
|
| Mean (SD) |
424000 (15490) |
39187 (13753) |
39284 (14083) |
40605 (14403) |
| Household median income (%) |
|
|
|
|
| Low |
24.4 |
30.9 |
31.2 |
27.6 |
| Moderate |
32.5 |
34.2 |
33.9 |
33.8 |
| High |
43.1 |
34.9 |
34.9 |
38.6 |
| PM2.5 (μg/m3) |
|
|
|
|
| Mean (SD) |
13.6 (1.7) |
13.6 (1.8) |
13.7 (1.7) |
13.6 (1.8) |
| Interquartile range |
2.0 |
2.3 |
2.0 |
2.3 |
| O3 in ppb |
|
|
|
|
| Mean (SD) |
43.2 (4.0) |
43.3 (5.0) |
43.3 (4.1) |
43.2 (5.0) |
| Interquartile range | 5.9 | 7.4 | 6.0 | 7.5 |