Table 1 Demographic characteristics of births in the United States from 2014–2018.
Total N (%) | Spontaneous Conception N (%) | ART/NIFT N (%) | p-value | ||
|---|---|---|---|---|---|
Infant Characteristics | |||||
Plurality | Single | 18,692,139 (96.6) | 18,473,643 (97.03) | 218,496 (70.28) | <0.001 |
Multiple | 658,205 (3.4) | 565,819 (2.97) | 92,386 (29.72) | ||
Gestational Age | <37 weeks | 2,213,605 (11.44) | 2,131,365 (11.19) | 82,240 (26.45) | <0.001 |
≥37 weeks | 17,123,968 (88.49) | 16,895,408 (88.74) | 228,560 (73.52) | ||
Missing | 12,771 (0.07) | 12,689 (0.07) | 82 (0.03) | ||
Z-score for birth weight | Mean | −0.96 | −0.94 | −0.19 | <0.001 |
Median | −0.12 | −0.12 | −0.2 | ||
IQR | −0.77, 0.53 | −0.77, 0.53 | −0.86, 0.46 | ||
Sex | Female | 9,450,921 (48.84) | 9,299,049 (48.84) | 151,872 (48.85) | 0.9 |
Congenital anomalies | 52,315 (0.27) | 51,002 (0.27) | 1313 (0.42) | <0.001 | |
Mode of delivery | Vaginal | 13,163,286 (68.03) | 13,021,841 (68.39) | 141,445 (45.50) | <0.001 |
C-section | 6,179,588 (31.94) | 6,010,216 (31.57) | 169,372 (54.48) | ||
Unknown/ Missing | 7470 (0.04) | 7405 (0.04) | 65 (0.02) | ||
NICU admission | 1,682,139 (8.69) | 1,615,794 (8.49) | 66,345 (21.34) | <0.001 | |
Maternal Characteristics | |||||
Age | Teen | 1,066,674 (5.51) | 1,066,500 (5.6) | 174 (0.06) | <0.001 |
20-34 years | 15,015,152 (77.6) | 14,850,747 (78) | 164,405 (52.88) | ||
≥35 years | 3,268,518 (16.89) | 3,122,215 (16.4) | 146,303 (47.06) | ||
Race | Non-Hispanic White | 10,081,496 (52.1) | 9,857,611 (51.77) | 223,885 (72.02) | <0.001 |
Non-Hispanic Black | 2,769,939 (14.31) | 2,755,205 (14.47) | 14,734 (4.74) | ||
Non-Hispanic Asian | 1,214,779 (6.28) | 1,181,469 (6.21) | 33,310 (10.71) | ||
Hispanic | 4,520,235 (23.36) | 4,493,955 (23.60) | 26,280 (8.45) | ||
Non-Hispanic Other Race (including more than one race) | 600,740 (3.1) | 595,089 (3.13) | 5651 (1.82) | ||
Unknown/ Not stated | 163,155 (0.84) | 156,133 (0.82) | 7022 (2.26) | ||
Insurance | Private | 9,382,636 (48.49) | 9,103,654 (47.81) | 278,982 (89.74) | <0.001 |
Medicaid | 8,240,991 (42.59) | 8,223,501 (43.19) | 17,490 (5.63) | ||
Self-Pay | 820,215 (4.24) | 814,669 (4.28) | 5546 (1.78) | ||
Other | 775,951 (4.01) | 768,442 (4.04) | 7509 (2.42) | ||
Missing | 130,551 (0.67) | 129,196 (0.68) | 1355 (0.44) | ||
SES | High | 5,981,771 (30.91) | 5,754,602 (30.22) | 227,169 (73.07) | <0.001 |
Low | 7,044,809 (36.41) | 7,034,872 (36.95) | 9937 (3.2) | ||
Other | 5,958,767 (30.79) | 5,893,391 (30.95) | 65,376 (21.03) | ||
Missing | 364,997 (1.89) | 356,597 (1.87) | 8400 (2.7) | ||
Education | High School degree or less | 11,475,041 (59.30) | 11,415,454 (59.96) | 59,587 (19.17) | <0.001 |
Higher Degree (Community College/ University degree) | 7,634,169 (39.45) | 7,389,982 (38.81) | 244,187 (78.55) | ||
Missing | 241,134 (1.25) | 234,026 (1.23) | 7108 (2.29) | ||
BMI | Underweight | 656,342 (3.39) | 649,228 (3.41) | 7114 (2.29) | <0.001 |
Normal | 8,299,572 (42.89) | 8,151,798 (42.82) | 147,774 (47.53) | ||
Overweight | 4,898,841 (25.32) | 4,821,751 (25.33) | 77,090 (24.80) | ||
Obese | 4,938,400 (25.52) | 4,865,696 (25.56) | 72,704 (23.39) | ||
Missing | 557,189 (2.88) | 550,989 (2.89) | 6200 (1.99) | ||
Smoker | 1,882,965 (9.73) | 1,876,608 (9.86) | 6357 (2.04) | <0.001 | |
Trimester prenatal care began | No prenatal care | 308,670 (1.6) | 308,051 (1.62) | 619 (0.2) | <0.001 |
1st | 14,463,318 (74.74) | 14,190,013 (74.53) | 273,305 (87.91) | ||
2nd | 3,150,469 (16.28) | 3,124,587 (16.41) | 25,882 (8.33) | ||
3rd | 849,057 (4.39) | 844,773 (4.44) | 4284 (1.38) | ||
Missing | 578,830 (2.99) | 572,038 (3) | 6792 (2.18) | ||
Number of prenatal visits (mean [SD]) | 13.6 (14.8) | 13.6 (14.8) | 14.6 (13.5) | <0.001 | |
