Table 3a.
Adjusted odds ratio for all PTB and IPI stratified on race/ethnicity1
| Race/ethnicity | Interpregnancy interval | 20–36 weeks | 20–23 weeks | 24–31 weeks | 32–36 weeks | ||||
|---|---|---|---|---|---|---|---|---|---|
| n | OR (95% CI) | n | OR (95% CI) | n | OR (95% CI) | n | OR (95% CI) | ||
| Non-Hispanic White | < 6 months | 1533 | 1.64 (1.54,1.76) | 22 | 1.90 (1.06,3.39) | 169 | 2.17 (1.77,2.68) | 1342 | 1.59 (1.48,1.71) |
| 6–11 months | 2897 | 1.16 (1.10,1.22) | 23 | 0.87 (0.50,1.53) | 278 | 1.41 (1.17,1.69) | 2596 | 1.14 (1.08,1.21) | |
| 12–17 months | 3344 | 1.04 (0.99,1.10) | 22 | 0.70 (0.40,1.24) | 272 | 1.10 (0.91,1.31) | 3050 | 1.04 (0.99,1.10) | |
| 18–23 months | 2697 | 1.0 (ref) | 26 | 1.0 (ref) | 209 | 1.0 (ref) | 2462 | 1.0 (ref) | |
| 24–29 months | 2062 | 1.00 (0.95,1.06) | 17 | 0.86 (0.46,1.58) | 182 | 1.14 (0.93,1.39) | 1863 | 0.99 (0.93,1.06) | |
| 30–35 months | 1643 | 1.09 (1.02,1.16) | 16 | 1.07 (0.57,2.00) | 139 | 1.16 (0.94,1.45) | 1488 | 1.08 (1.01,1.16) | |
| 36–47 months | 2243 | 1.11 (1.05,1.18) | 16 | 0.79 (0.42,1.47) | 206 | 1.28 (1.05,1.55) | 2021 | 1.10 (1.03,1.17) | |
| 48–59 months | 1575 | 1.23 (1.16,1.32) | 15 | 1.14 (0.60,2.17) | 152 | 1.46 (1.18,1.80) | 1408 | 1.21 (1.13,1.30) | |
| ≥ 60 months | 4600 | 1.35 (1.29,1.43) | 62 | 1.77 (1.10,2.87) | 526 | 1.83 (1.55,2.17) | 4012 | 1.30 (1.24,1.38) | |
| Non-Hispanic Black | < 6 months | 918 | 1.49 (1.34,1.65) | 12 | 1.59 (0.67,3.81) | 131 | 1.46 (1.13,1.89) | 775 | 1.49 (1.33,1.66) |
| 6–11 months | 1182 | 1.19 (1.08,1.31) | 22 | 1.80 (0.83,3.92) | 154 | 1.06 (0.82,1.35) | 1006 | 1.20 (1.08,1.33) | |
| 12–17 months | 916 | 1.02 (0.92,1.13) | 20 | 1.86 (0.85,4.09) | 114 | 0.86 (0.66,1.12) | 782 | 1.03 (0.92,1.15) | |
| 18–23 months | 754 | 1.0 (ref) | 9 | 1.0 (ref) | 110 | 1.0 (ref) | 635 | 1.0 (ref) | |
| 24–29 months | 593 | 0.94 (0.84,1.06) | 10 | 1.31 (0.53,3.23) | 86 | 0.92 (0.70,1.23) | 497 | 0.94 (0.83,1.06) | |
| 30–35 months | 521 | 0.99 (0.88,1.12) | 8 | 1.26 (0.49,3.28) | 72 | 0.93 (0.69,1.26) | 441 | 1.00 (0.88,1.13) | |
| 36–47 months | 912 | 1.08 (0.97,1.19) | 20 | 1.95 (0.89,4.29) | 145 | 1.15 (0.90,1.48) | 747 | 1.05 (0.94,1.17) | |
| 48–59 months | 696 | 1.12 (1.00,1.25) | 15 | 2.01 (0.87,4.61) | 100 | 1.07 (0.82,1.41) | 581 | 1.11 (0.99,1.25) | |
| ≥ 60 months | 2645 | 1.31 (1.20,1.43) | 64 | 2.74 (1.34,5.62) | 524 | 1.68 (1.35,2.08) | 2057 | 1.22 (1.10,1.34) | |
1
adjusted for prepregnancy BMI, parity, education, medical payer, smoking during pregnancy, initiation of PNC, previous PTB, and age