Table 1.
Demographic factors by maternal age group among twin pregnancies
| Maternal age, years | 15–17, n (%) | 18–24, n (%) | 25–29, n (%) | 30–34, n (%) | 35–39, n (%) | ≥40, n (%) |
|
| ||||||
| All patients | 7,192 | 136,986 | 182,008 | 205,138 | 120,301 | 41,611 |
|
| ||||||
| Education | ||||||
| ≤8th grade | 489 (6.8) | 4,404 (3.2) | 5,474 (3.0) | 5,477 (2.7) | 3,521 (2.9) | 981 (2.4) |
| 9th–12th grade | 5,689 (79.2) | 28,995 (21.2) | 16,520 (9.1) | 10,064(4.9) | 4,664 (3.9) | 1,018 (2.5) |
| High school | 865 (12.0) | 55,296 (40.4) | 42,411 (23.3) | 29,356 (14.3) | 14,511 (12.1) | 3,929 (9.4) |
| Some College | 0 | 35,318 (25.8) | 42,387 (23.3) | 33,056 (16.1) | 16,271 (13.5) | 4,765 (11.5) |
| Associate Degree | 0 | 5,973 (4.4) | 17,952 (9.9) | 18,065 (8.8) | 9,723 (8.1) | 2,902 (7) |
| Bachelor’s degree | 0 | 5,187 (3.8) | 39,883 (21.9) | 62,052 (30.3) | 37,192 (30.9) | 13,287 (31.9) |
| Master’s degree | 0 | 392 (0.3) | 12,854 (7.1) | 33,931 (16.5) | 22,911 (19.0) | 8,450 (20.3) |
| Doctorate | 0 | 48 (0.0) | 2,188 (1.2) | 9,990 (4.9) | 9,022 (7.5) | 4,093 (9.8) |
| Unknown | 99 (1.4) | 1,373 (1.0) | 2339 (1.3) | 3,147 (1.5) | 2,486 (2.1) | 2,186 (5.3) |
| Parity | ||||||
| 0 | 3,745 (52.1) | 39,606 (28.9) | 43,217 (23.7) | 48,171 (23.5) | 26,664 (22.2) | 11,165 (26.8) |
| 1 | 3,002 (41.7) | 53,596 (39.1) | 62,247 (34.2) | 70,029 (28.8) | 40,153 (33.4) | 14,277 (34.3) |
| 2 | 363 (5.1) | 28,196 (20.6) | 40,978 (22.5) | 44,362 (21.6) | 25,843 (21.5) | 7,460 (17.9) |
| ≥3 | 82 (1.1) | 14,488 (11.4) | 35,656 (19.6) | 42,576 (20.8) | 27,641 (23.0) | 8,709 (20.9) |
| Marital Status | ||||||
| Married | 364 (5.1) | 44,414 (32.4) | 121,901 (67.0) | 167,493 (81.7) | 101,861 (84.7) | 35,139 (84.5) |
| Not married | 6,828 (94.9) | 92,572 (67.6) | 60,107 (33.0) | 37,645 (18.3) | 18,440 (15.3) | 6,472 (15.6) |
| Race | ||||||
| Non-Hispanic white | 2,253 (31.3) | 61,718 (45.1) | 108,055 (59.4) | 133,025 (64.9) | 76,667 (63.7) | 27,010 (64.9) |
| Non-Hispanic black | 2,021 (28.1) | 37,539 (27.4) | 30,183 (16.6) | 23,139 (11.3) | 12,010 (10.0) | 3,571 (8.6) |
| Non-Hispanic other | 154 (2.1) | 3,783 (2.8) | 8,708 (4.8) | 15,149 (7.4) | 10,999 (9.1) | 3,799 (9.1) |
| Hispanic | 2,2713 (37.7) | 32,979 (24.1) | 33,471 (18.4) | 31,533 (15.4) | 18,633 (15.5) | 5,404 (13.0) |
| Unknown | 51 (0.7) | 967 (0.7) | 1,591 (0.9) | 2,281 (1.1) | 1,992 (1.7) | 1,827 (4.4) |
| PDM | ||||||
| Present | 26 (0.4) | 689 (0.5) | 1,394 (0.8) | 1,906 (0.9) | 1,318 (1.1) | 467 (1.1) |
| Absent | 7,104 (98.8) | 135,348 (98.8) | 179,708 (98.7) | 202,375 (98.7) | 118,557 (98.6) | 40,974 (98.5) |
| Unknown | 60 (0.8) | 949 (0.7) | 906 (0.5) | 857 (0.4) | 426 (0.4) | 170 (0.4) |
| Chronic HTN | ||||||
| Present | 64 (0.9) | 1,769 (1.3) | 3,237 (1.8) | 4,280 (2.1) | 3,162 (2.6) | 1,496 (3.6) |
| Absent | 7,068 (98.3) | 134,268 (98.0) | 177,865 (97.7) | 200,001 (97.5) | 116,713 (97.0) | 39,945 (96.0) |
| Unknown | 60 (0.8) | 949 (0.7) | 906 (0.5) | 857 (0.4) | 426 (0.4) | 170 (0.4) |
| Year | ||||||
| 2007 | 1,054 (14.7) | 16,414 (12) | 19,699 (10.8) | 20,253 (9.9) | 12,702 (10.6) | 3,894 (9.4) |
| 2008 | 1,151 (16.0) | 18,407 (13.4) | 22,978 (12.6) | 24,037 (11.7) | 15,176 (12.6) | 5,088 (12.2) |
| 2009 | 1,148 (16.0) | 18,969 (13.9) | 23,669 (13.0) | 25,531 (12.5) | 15,184 (12.6) | 5,429 (13.1) |
| 2010 | 1,032 (14.4) | 19,812 (14.5) | 26,344 (14.5) | 29,260 (14.3) | 17,327 (14.4) | 6,076 (14.6) |
| 2011 | 1,066 (14.8) | 21,316 (15.6) | 28,962 (15.9) | 33,424 (16.3) | 19,013 (15.8) | 6,784 (16.3) |
| 2012 | 910 (12.7) | 20,930 (15.3) | 29,414 (16.2) | 35,678 (17.4) | 20,150 (16.8) | 7,129 (17.1) |
| 2013 | 831 (11.6) | 21,138 (15.4) | 30,942 (17.0) | 36,955 (18.0) | 20,749 (17.3) | 7,211 (17.3) |
Comparisons for all demographic and medical variables differed significantly by maternal age category (p <0.001). PDM, pregestational diabetes mellitus; HTN, hypertension. Demographics were calculated based on data reported in the 2003 revised birth certificate format.