Table 1.
Maternal and child characteristics by gestational age at delivery, Collaborative Perinatal Project (n = 39 199)
| Gestational age at delivery (weeks) |
|||||||
|---|---|---|---|---|---|---|---|
| Full samplea | 37 | 38 | 39 | 40 | 41 | 42+ | |
| Total [n (%)] | 39 199 | 3028 (7.7) | 5570 (14.2) | 8705 (22.2) | 9370 (23.9) | 6104 (15.6) | 6422 (16.4) |
| Maternal characteristics | |||||||
| Age [mean (SD)] | 24.1 (5.9) | 23.7 (6.2) | 24.1 (5.9) | 24.2 (5.9) | 24.2 (5.8) | 24.0 (5.9) | 23.8 (5.9) |
| Socio-economic index [n (%)] | |||||||
| 0–1.9 | 2802 (7.4) | 290 (9.9) | 436 (8.1) | 619 (7.3) | 576 (6.3) | 384 (6.5) | 497 (8.0) |
| 2–3.9 | 11 838 (31.1) | 1080 (36.9) | 1770 (32.7) | 2544 (30.1) | 2634 (28.8) | 1666 (28.1) | 2144 (34.6) |
| 4–5.9 | 11 839 (31.1) | 945 (32.2) | 1740 (32.2) | 2640 (31.2) | 2823 (30.9) | 1776 (30.0) | 1915 (30.9) |
| 6–7.9 | 7609 (19.9) | 425 (14.5) | 1007 (18.6) | 1744 (20.6) | 1978 (21.7) | 1346 (22.7) | 1109 (17.9) |
| 8–9.9 | 3979 (10.5) | 191 (6.5) | 456 (8.4) | 915 (10.8) | 1122 (12.3) | 756 (12.8) | 539 (8.7) |
| Parity [n (%)] | |||||||
| 0 | 12 278 (31.7) | 922 (30.9) | 1672 (30.3) | 2648 (30.7) | 2985 (32.1) | 2043 (33.8) | 2008 (31.7) |
| 1 | 8913 (23.0) | 661 (22.1) | 1280 (23.2) | 2042 (23.7) | 2191 (23.6) | 1385 (22.9) | 1354 (21.4) |
| 2 | 6188 (15.9) | 491 (16.4) | 900 (16.3) | 1423 (16.5) | 1430 (15.4) | 918 (15.2) | 1026 (16.2) |
| 3+ | 11 415 (29.4) | 913 (30.6) | 1666 (30.2) | 2508 (29.1) | 2682 (28.9) | 1697 (28.1) | 1949 (30.8) |
| Marital status [n (%)] | |||||||
| Single | 5652 (14.4) | 556 (18.4) | 894 (16.1) | 1202 (13.8) | 1236 (13.2) | 805 (13.2) | 959 (14.9) |
| Married/living with partner | 30 405 (77.6) | 2222 (73.4) | 4241 (76.1) | 6873 (79.0) | 7438 (79.4) | 4818 (78.9) | 4813 (75.0) |
| Divorced, widowed, separated | 3142 (8.0) | 250 (8.3) | 435 (7.8) | 630 (7.2) | 696 (7.4) | 481 (7.9) | 650 (10.1) |
| Ever smoked this pregnancy [n (%)] | 23 526 (60.7) | 1752 (58.7) | 3293 (59.7) | 5130 (59.5) | 5696 (61.4) | 3720 (61.8) | 3935 (62.2) |
| Gestational hypertension [n (%)] | 708 (1.8) | 44 (1.5) | 94 (1.7) | 125 (1.4) | 188 (2.0) | 134 (2.2) | 123 (1.9) |
| Pre-eclampsia [n (%)] | 940 (2.4) | 81 (2.7) | 162 (2.9) | 189 (2.2) | 221 (2.4) | 129 (2.1) | 158 (2.5) |
| Child characteristics | |||||||
| Sex, male [n (%)] | 19 444 (49.6) | 1408 (46.5) | 2689 (48.3) | 4276 (49.1) | 4657 (49.7) | 3205 (52.5) | 3209 (50.0) |
| Race/ethnicity [n (%)] | |||||||
| White | 18 628 (47.5) | 1010 (33.4) | 2104 (37.8) | 3222 (42.4) | 4931 (52.6) | 3433 (56.2) | 3205 (49.9) |
| Black | 17 557 (44.8) | 1747 (57.7) | 3050 (54.8) | 3834 (50.4) | 3792 (40.5) | 2225 (36.5) | 2652 (41.3) |
| Asian | 196 (0.5) | 13 (0.4) | 45 (0.8) | 49 (0.6) | 39 (0.4) | 30 (0.5) | 20 (0.3) |
| Puerto Rican | 2508 (6.4) | 231 (7.6) | 294 (6.7) | 559 (6.4) | 529 (5.7) | 361 (5.9) | 490 (7.6) |
| Other | 309 (0.8) | 27 (0.9) | 33 (0.8) | 61 (0.7) | 78 (0.8) | 55 (0.9) | 55 (0.9) |
a
Liveborn singletons born at 37+ weeks, admitted to hospital in spontaneous labour, excluding infant death <8 months.