Table 1 Demographic characteristics and crude odds ratios (95% CI) for preterm birth.a
Parameter | Preterm Cases (N = 10,265) n (%) or mean ± SD | Cohort (N = 111,203) n (%) or mean ± SD | Crude Preterm OR (95% CI) |
|---|---|---|---|
Gestational age (days) | 244 (17.0) | 275 (14.6) | -- -- -- |
Birth weight (g) | 2970 (643) | 3342 (489) | -- |
Infant's sex | Â | Â | Â |
Female | 4790 (46.7) | 54665 (49.2) | 0.91 (0.88-0.95) |
Male | 5474 (53.3) | 56537 (50.8) | 1.00 |
Missing | 1 | 1 | Â |
Maternal age (years) | Â | Â | Â |
< 20 | 1336 (13.0) | 13185 (11.9) | 1.15 (1.08-1.24) |
20-24 | 2555 (24.9) | 28409 (25.6) | 1.03 (0.97-1.09) |
25-29 | 2556 (24.9) | 29508 (26.5) | 1.00 |
30-34 | 2121 (20.7) | 24347 (21.9) | 0.99 (0.94-1.06) |
≥ 35 | 1697 (16.5) | 15751 (14.2) | 1.26 (1.18-1.35) |
Missing | Â | 3 | Â |
Maternal race/ethnicity | Â | Â | Â |
Hispanic | 7749 (75.8) | 83947 (75.7) | 1.36 (1.25-1.47) |
White, non-Hispanic | 588 (5.8) | 8696 (7.8) | 1.00 |
African American | 1014 (9.9) | 8472 (7.6) | 1.79 (1.62-1.98) |
Asian | 474 (4.6) | 5938 (5.4) | 1.19 (1.05-1.34) |
Otherb | 398 (3.9) | 3839 (3.5) | 1.47 (1.29-1.66) |
Missing | 42 | 311 | Â |
Maternal education (years) | Â | Â | Â |
≤ 8 | 1854 (18.2) | 18169 (16.5) | 1.09 (1.03-1.15) |
9-12 | 5948 (58.6) | 61957 (56.1) | 1.00 |
13-15 | 1422 (14.0) | 16605 (15.1) | 0.88 (0.83-0.94) |
≥ 16 | 935 (9.2) | 13635 (12.3) | 0.71 (0.66-0.77) |
Missing | 106 | 837 | Â |
Parity | Â | Â | Â |
0 | 3535 (34.5) | 41376 (37.2) | 0.88 (0.84-0.92) |
1 or more | 6724 (65.5) | 69787 (62.8) | 1.00 |
Missing | 6 | 40 | Â |
Prenatal care | Â | Â | Â |
No prenatal care or started after 1st trimester | 1287 (12.6) | 10060 (9.1) | 1.51 (1.41-1.60) |
Started in first trimester | 8935 (87.4) | 100784 (90.9) | 1.00 |
Missing | 43 | 359 | Â |
Mother's birthplace (U.S. vs outside U.S.) | Â | Â | Â |
U.S. Born | 4096 (40.0) | 42933 (38.6) | 1.06 (1.01-1.10) |
Foreign Born | 6158 (60.0) | 68187 (61.4) | 1.00 |
Missing | 11 | 83 | Â |
Mother's birthplace | Â | Â | Â |
U.S. | 4096 (40.0) | 42933 (38.6) | 1.00 |
Mexico | 4048 (39.5) | 45090 (40.6) | 0.94 (0.90-0.98) |
Other outside U.S. (includes Puerto Rico) | 2110 (20.5) | 23097 (20.8) | 0.96 (0.91-1.01) |
Missing | 11 | 83 | Â |
Primary payment for prenatal care | Â | Â | Â |
Private insurance/HMO/Pre-paid/Blue Cross-Blue Shield | 2415 (23.9) | 31685 (28.8) | 1.00 |
Medi-Cal, other government programs, self pay, no care | 7670 (76.1) | 78283 (71.2) | 1.30 (1.24-1.36) |
Missing | 180 | 1235 | Â |
Census-based SES index (quintiles) | Â | Â | Â |
Q1 | 7237 (70.5) | 74587 (67.1) | 1.63 (1.32-2.02) |
Q2 | 1710 (16.7) | 19319 (17.4) | 1.49 (1.20-1.85) |
Q3 | 863 (8.4) | 10737 (9.7) | 1.35 (1.08-1.69) |
Q4 | 364 (3.5) | 5062 (4.5) | 1.19 (0.94-1.50) |
Q5 | 91 (0.89) | 1498 (1.3) | 1.00 |