Table 1 Characteristics of all participants
From: Maternal preterm birth prediction in the United States: a case-control database study
Variables | 2019 (n = 3,006,989) | 2018 (n = 3,039,922) |
|---|---|---|
Age (years), n (%) | ||
 < 35 | 2,415,844 (80.34) | 2,455,582 (80.78) |
 ≥ 35 | 591,145 (19.66) | 584,340 (19.22) |
Race, n (%) | ||
 White | 2,306,813 (76.72) | 2,342,911 (77.07) |
 Black | 385,213 (12.81) | 381,387 (12.55) |
 Other | 314,963 (10.47) | 315,624 (10.38) |
Education, n (%) | ||
 High school or below | 1,868,219 (62.13) | 1,902,319 (62.58) |
 Bachelor | 707,428 (23.53) | 708,539 (23.31) |
 Master or above | 431,342 (14.34) | 429,064 (14.11) |
Age of spouse (years), n (%) | ||
 < 35 | 1,125,350 (37.42) | 1,149,463 (37.81) |
 ≥ 35 | 1,881,639 (62.58) | 1,890,459 (62.19) |
Race of spouse, n (%) | ||
 White | 2,145,381 (71.35) | 2,190,206 (72.05) |
 Black | 437,487 (14.55) | 432,525 (14.23) |
 Other | 424,121 (14.10) | 417,191 (13.72) |
Education of spouse, n (%) | ||
 High school or below | 2,049,096 (68.14) | 2,077,147 (68.33) |
 Bachelor | 611,655 (20.34) | 613,242 (20.17) |
 Master or above | 346,238 (11.51) | 349,533 (11.50) |
Pre-pregnancy BMI (kg/m2), n (%) | ||
 Underweight | 86,346 (2.87) | 91,667 (3.02) |
 Normal | 1,254,721 (41.73) | 1,302,458 (42.85) |
 Overweight | 815,799 (27.13) | 814,083 (26.78) |
 Obesity | 850,123 (28.27) | 831,714 (27.36) |
Prenatal care, n (%) | ||
 No | 35,112 (1.17) | 32,015 (1.05) |
 Yes | 2,971,877 (98.83) | 3,007,907 (98.95) |
Pregnancy smoking, n (%) | ||
 No | 2,870,310 (95.45) | 2,888,128 (95.01) |
 Yes | 136,679 (4.55) | 151,794 (4.99) |
Pre-pregnancy diabetes, n (%) | ||
 No | 2,978,600 (99.06) | 3,012,207 (99.09) |
 Yes | 28,389 (0.94) | 27,715 (0.91) |
Gestation diabetes, n (%) | ||
 No | 2,791,240 (92.83) | 2,828,904 (93.06) |
 Yes | 215,749 (7.17) | 211,018 (6.94) |
Pre-pregnancy hypertension, n (%) | ||
 No | 2,944,019 (97.91) | 2,980,984 (98.06) |
 Yes | 62,970 (2.09) | 58,938 (1.94) |
Gestation hypertension, n (%) | ||
 No | 2,776,000 (92.32) | 2,825,319 (92.94) |
 Yes | 230,989 (7.68) | 214,603 (7.06) |
Hypertension eclampsia, n (%) | ||
 No | 2,999,359 (99.75) | 3,032,983 (99.77) |
 Yes | 7630 (0.25) | 6939 (0.23) |
Previous preterm birth, n (%) | ||
 No | 2,906,623 (96.66) | 2,940,996 (96.75) |
 Yes | 100,366 (3.34) | 98,926 (3.25) |
Previous cesareans, n (%) | ||
 No | 2,536,384 (84.35) | 2,560,142 (84.22) |
 Yes | 470,605 (15.65) | 479,780 (15.78) |
Infections, n (%) | ||
 No | 2,947,151 (98.01) | 2,980,523 (98.05) |
 Yes | 59,838 (1.99) | 59,399 (1.95) |
Plurality, n (%) | ||
 No | 2,912,136 (96.85) | 2,942,193 (96.79) |
 Yes | 94,853 (3.15) | 97,729 (3.21) |
Preterm birth, n (%) | ||
 No | 2,682,289 (89.20) | 2,725,371 (89.65) |
 Yes | 324,700 (10.80) | 314,551 (10.35) |