Table 1.
Descriptive statistics.
| Preterm | Birth Weight (g) | ||||
|---|---|---|---|---|---|
| N | No (%) | Yes (%) | Mean | SD | |
| Month of Birth | |||||
| January | 35,053 | 29,899 (85.30%) | 5154 (14.70%) | 3241 | 495.7 |
| February | 33,695 | 28,874 (85.69%) | 4821 (14.31%) | 3247.8 | 489.5 |
| March | 37,982 | 32,631 (85.91%) | 5351 (14.09%) | 3255 | 485.8 |
| April | 37,200 | 31,985 (85.98%) | 5215 (14.02%) | 3257.7 | 487.6 |
| May | 38,396 | 33,056 (86.09%) | 5340 (13.91%) | 3257.4 | 489.9 |
| June | 37,820 | 32,401 (85.67%) | 5419 (14.33%) | 3256.6 | 491.3 |
| July | 39,411 | 34,104 (86.53%) | 5307 (13.47%) | 3252.1 | 487.7 |
| August | 39,581 | 34,111 (86.18%) | 5470 (13.82%) | 3256.6 | 485.8 |
| September | 38,606 | 33,567 (86.95%) | 5039 (13.05%) | 3256.8 | 482.8 |
| October | 37,372 | 32,364 (86.60%) | 5008 (13.40%) | 3257 | 484.9 |
| November | 35,203 | 30,224 (85.86%) | 4979 (14.14%) | 3251.6 | 490.6 |
| December | 36,642 | 31,309 (85.45%) | 5333 (14.55%) | 3241.3 | 490.5 |
| Number of Prenatal Visits | |||||
| <10 | 177,945 | 145,903 (81.99%) | 32,042 (18.01%) | 3194.2 | 511.5 |
| 10+ | 269,016 | 238,622 (88.70%) | 30,394 (11.30%) | 3291.5 | 468.6 |
| Birth Year | |||||
| 2007 | 47,648 | 40,627 (85.27%) | 7021 (14.73%) | 3242.3 | 486.8 |
| 2008 | 50,302 | 42,732 (84.95%) | 7570 (15.05%) | 3249.2 | 485.3 |
| 2009 | 50,840 | 43,487 (85.54%) | 7353 (14.46%) | 3251 | 487.5 |
| 2010 | 50,056 | 43,055 (86.01%) | 7001 (13.99%) | 3251.4 | 486.4 |
| 2011 | 49,604 | 42,964 (86.61%) | 6640 (13.39%) | 3254.3 | 488.6 |
| 2012 | 49,029 | 42,289 (86.25%) | 6740 (13.75%) | 3256.8 | 487 |
| 2013 | 49,658 | 43,140 (86.87%) | 6518 (13.13%) | 3257 | 490 |
| 2014 | 49,816 | 43,234 (86.79%) | 6582 (13.21%) | 3257.7 | 490.6 |
| 2015 | 50,008 | 42,997 (85.98%) | 7011 (14.02%) | 3254.6 | 493.8 |
| Mother’s Race and Ethnicity | |||||
| Hispanic | 116,570 | 99,546 (85.40%) | 17,024 (14.60%) | 3237.6 | 489.4 |
| Non-Hispanic Non-White | 46,068 | 38,533 (83.64%) | 7535 (16.36%) | 3152.7 | 496.2 |
| Non-Hispanic White | 284,323 | 246,446 (86.68%) | 37,877 (13.32%) | 3275.1 | 484.5 |
| Mother Smoked in Any Trimester | |||||
| No | 413,081 | 356,755 (86.36%) | 56,326 (13.64%) | 3266.9 | 485 |
| Yes | 33,880 | 27,770 (81.97%) | 6110 (18.03%) | 3080.6 | 497.5 |
| Income | |||||
| <$15,000 | 102,329 | 86,249 (84.29%) | 16,080 (15.71%) | 3180.9 | 498.5 |
| $15,000–$24,999 | 56,126 | 47,909 (85.36%) | 8217 (14.64%) | 3227.5 | 490.3 |
| $25,000–$34,999 | 44,007 | 37,472 (85.15%) | 6535 (14.85%) | 3248.3 | 493.4 |
| $35,000–$49,999 | 45,057 | 38,936 (86.41%) | 6121 (13.59%) | 3271 | 483.2 |
| $50,000–$44,999 | 69,796 | 60,575 (86.79%) | 9221 (13.21%) | 3288.8 | 483.4 |
| $75,000+ | 129,646 | 113,384 (87.46%) | 16,262 (12.54%) | 3296.2 | 475.1 |
| Mother Drank Alcohol in Any Trimester | |||||
| No | 442,168 | 380,403 (86.03%) | 61,765 (13.97%) | 3253.3 | 488.3 |
| Yes | 4793 | 4122 (86.00%) | 671 (14.00%) | 3202.9 | 499.1 |
| Mother’s Level of Education | |||||
| Less Than High School | 64,722 | 54,898 (84.82%) | 9824 (15.18%) | 3210.5 | 501.5 |
| High School | 219,354 | 186,439 (85.00%) | 32,915 (15.00%) | 3231.7 | 490.7 |
| Bachelors | 107,840 | 94,834 (87.94%) | 13,006 (12.06%) | 3300.2 | 476 |
| Higher than Bachelors | 55,045 | 48,354 (87.84%) | 6691 (12.16%) | 3293.2 | 477.9 |
| Mother has Asthma | |||||
| No | 426,436 | 367,162 (86.10%) | 59,274 (13.90%) | 3254.7 | 488 |
| Yes | 20,525 | 17,363 (84.59%) | 3162 (15.41%) | 3211.5 | 497 |
| Mother’s Age | |||||
| <18 | 8221 | 6918 (84.15%) | 1303 (15.85%) | 3134.8 | 479.8 |
| 18–35 | 382,590 | 330,139 (86.29%) | 52,451 (13.71%) | 3253.2 | 484.3 |
| >35 | 56,150 | 47,468 (84.54%) | 8682 (15.46%) | 3266.9 | 515.1 |
| Low Birth Weight | |||||
| No | 419,920 | 376,816 (89.74%) | 43,104 (10.26%) | 3321.6 | 411.3 |
| Yes | 27041 | 7709 (28.51%) | 19,332 (71.49%) | 2182.7 | 312.1 |
| GINDEX | |||||
| Intensive | 27,956 | 23,865 (85.37%) | 4091 (14.63%) | 3284.2 | 504.6 |
| Adequate | 262,554 | 229,839 (87.54%) | 32,715 (12.46%) | 3274.5 | 480.8 |
| Intermediate | 120,595 | 101,608 (84.26%) | 18,987 (15.74%) | 3220.4 | 489.6 |
| Inadequate | 31,194 | 25,441 (81.56%) | 5753 (18.44%) | 3176.1 | 511.1 |
| No prenatal care | 6 | 2 (33.33%) | 4 (66.67%) | 2780 | 605 |
| Missing | 4656 | 3770 (80.97%) | 886 (19.03%) | 3189.2 | 527 |
| Total | 446,961 | 384,525 (86.03%) | 62,436 (13.97%) | ||