Table 1.
Subject demography information
| Variable | Newborn Gestational Age | |
|---|---|---|
| < 34 weeks: ePTB | ≥ 34 weeks | |
| N = 134009 | N = 3860863 | |
| Mothers’ Age (%) | ||
| ≤ 24 Years | 40711 (30.38) | 1094793 (28.36) |
| 25-29 Years | 34831 (25.99) | 1112643 (28.82) |
| 30-34 Years | 33578 (25.06) | 1049775 (27.19) |
| ≥ 35 Years | 24889 (18.57) | 603652 (15.64) |
| Mothers’ Nativity (%) | ||
| Born in U.S. | 107578 (80.28) | 2996531 (77.61) |
| Born Outside U.S. /Unknown/Not Stated | 26431 (19.72) | 864332 (22.39) |
| Mothers’ Race (%) | ||
| White | 88185 (65.81) | 2938466 (76.11) |
| Black | 36554 (27.28) | 603921 (15.64) |
| American Indian/Alaskan Native/Asian or Pacific Islander | 9270 (6.92) | 318476 (8.25) |
| Mothers’ Hispanic Origin (%) | ||
| Non-Hispanic/Hispanic Origin Not Stated | 105011 (78.36) | 2968422 (76.88) |
| Hispanic | 28998 (21.64) | 892441 (23.12) |
| Marital Status (%) | ||
| Married | 65594 (48.95) | 2323620 (60.18) |
| Unmarried | 68415 (51.05) | 1537243 (39.82) |
| Mothers’ Education (%) | ||
| ≤ High School or GED/Unknown | 62819 (46.88) | 1512489 (39.17) |
| Associate/Some College Credit | 37338 (27.86) | 1086153 (28.13) |
| ≥ Bachelor's | 29145 (21.75) | 1124077 (29.11) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Pre-pregnancy Smoking Status (%) | ||
| Nonsmoker | 108663 (81.09) | 3258557 (84.40) |
| Smoker/Unknown/Not Stated | 20639 (15.40) | 464162 (12.02) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Pre-pregnancy BMI (%) | ||
| Under Weight-Normal ≤ 24.9 | 55824 (41.66) | 1785913 (46.26) |
| Overweight 25.0-29.9 | 30288 (22.60) | 918380 (23.79) |
| Obesity ≥ 30.0/Unknown/Not Stated | 43190 (32.23) | 1018426 (26.38) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Pre-pregnancy Diabetes Status (%) | ||
| No/Unknown/Not Stated | 126901 (94.70) | 3694967 (95.70) |
| Yes | 2401 (1.79) | 27752 (0.72) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Pre-pregnancy Hypertension Status (%) | ||
| No/Unknown/Not Stated | 123932 (92.48) | 3667289 (94.99) |
| Yes | 5370 (4.01) | 55430 (1.44) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Previous Preterm Birth Status (%) | ||
| No/Unknown/Not Stated | 118468 (88.40) | 3626879 (93.94) |
| Yes | 10834 (8.08) | 95840 (2.48) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Infertility Treatment Usage Status (%) | ||
| No/Unknown/Not Stated | 122859 (91.68) | 3669850 (95.05) |
| Yes | 6443 (4.81) | 52869 (1.37) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Fertility Enhancing Drug Usage Status (%) | ||
| No/Not Applicable/Unknown/Not Stated | 126582 (94.46) | 3697856 (95.78) |
| Yes | 2720 (2.03) | 24863 (0.64) |
| Missing | 4707 (3.51) | 138144 (3.58) |
| Delivery Payment Source (%) | ||
| Medicaid | 65048 (48.54) | 1598851 (41.41) |
| Private Insurance | 51753 (38.62) | 1771814 (45.89) |
| Self-pay/Other/Unknown | 12501 (9.33) | 352054 (9.12) |
| Missing | 4707 (3.51) | 138144 (3.58) |