Table 1.
Demographic statistics on study population stratified by injury status and department of hospital admittance
| Characteristics | Total cohort |
|||
| All (N=90 452), n (%) | Non-injured (n=86 891), n (%) | Injured* ‡ (n=3561), n (%) | Head or neck injuries (n=534), n (%) | |
| Maternal age at delivery (years) | ||||
| <25 | 8695 (9.6) | 8142 (9.4) | 553 (15.5) | 86 (16.1) |
| 25–29 | 34 726 (38.4) | 33 341 (38.4) | 1385 (38.9) | 194 (36.3) |
| 30–34 | 33 537 (37.1) | 32 392 (37.3) | 1145 (32.2) | 180 (33.7) |
| 35–39 | 12 006 (13.3) | 11 594 (13.3) | 412 (11.6) | 63 (11.8) |
| ≥40 | 1488 (1.6) | 1422 (1.6) | 66 (1.9) | 11 (2.1) |
| Gestational age at delivery (weeks) | ||||
| <34 | 1227 (1.5) | 1177 (1.4) | 50 (1.5) | 9 (1.8) |
| 34–36 | 2756 (3.2) | 2629 (3.2) | 127 (3.8) | 20 (4.0) |
| ≥37 | 82 642 (95.3) | 79 454 (95.4) | 3188 (94.7) | 475 (94.2) |
| Birth weight (g) | ||||
| <1500 | 538 (0.6) | 538 (0.6) | 18 (0.5) | 4 (0.8) |
| 1500–2499 | 2074 (2.5) | 2074 (2.5) | 101 (3.0) | 15 (3.0) |
| ≥2500 | 80 451 (96.9) | 80 451 (96.9) | 3238 (96.5) | 484 (96.2) |
| Sex of child | ||||
| Female | 42 284 (48.8) | 40 696 (48.8) | 1588 (47.2) | 236 (46.8) |
| Male | 44 435 (51.2) | 42 656 (51.2) | 1779 (52.8) | 268 (53.2) |
| Parity | ||||
| 1 | 39 224 (46.3) | 37 569 (47.2) | 1655 (50.7) | 238 (48.1) |
| 2 | 31 604 (37.3) | 30 463 (38.3) | 1141 (35.0) | 192 (38.8) |
| 3+ | 13 859 (16.4) | 11 593 (14.6) | 466 (14.3) | 65 (13.1) |
| Smoking status | ||||
| None | 64 589 (73.4) | 62 299 (73.7) | 2290 (66.7) | 344 (67.3) |
| Stopped during pregnancy | 12 530 (14.2) | 11 923 (14.1) | 607 (17.7) | 91 (17.8) |
| 1–10 | 10 725 (12.2) | 10 193 (12.1) | 532 (15.5) | 76 (14.9) |
| ≥10 | 120 (0.1) | 117 (0.1) | 3 (0.1) | 0 (0) |
| Average alcohol consumption (drinks/week) | ||||
| None | 41 325 (64.9) | 39 642 (64.7) | 1683 (68.8) | 270 (34.3) |
| 1 | 10 480 (16.5) | 10 124 (16.5) | 356 (14.5) | 466 (59.2) |
| 2 | 6872 (10.8) | 6649 (10.9) | 223 (9.1) | 29 (3.7) |
| 3 | 2554 (4.0) | 2462 (4.0) | 92 (3.8) | 7 (0.9) |
| 4+ | 2442 (3.8) | 2351 (3.8) | 91 (3.7) | 15 (1.977) |
| ≥5 at one time | 26 779 (30.8) | 25 663 (29.5) | 1116 (31.3) | 167 (31.2) |
| Household socioeconomic status | ||||
| Higher grade professionals | 20 713 (23.5) | 19 989 (23.6) | 724 (21.1) | 126 (24.7) |
| Middle-grade professionals | 27 304 (31.0) | 26 326 (31.1) | 978 (28.5) | 135 (26.4) |
| Skilled work | 24 577 (27.9) | 23 587 (27.9) | 990 (28.8) | 143 (28.0) |
| Unskilled work | 12 408 (14.1) | 11 804 (14.0) | 604 (17.6) | 83 (16.2) |
| Student | 2075 (2.4) | 1991 (2.4) | 84 (2.4) | 11 (2.2) |
| Unemployed >1 year | 683 (0.8) | 641 (0.8) | 42 (1.2) | 9 (1.8) |
| Unclassified | 204 (0.2) | 194 (0.2) | 10 (0.3) | 4 (0.8) |
| Partner cohabitation status | ||||
| Cohabits | 66 859 (99.0) | 64 359 (98.1) | 2500 (98.1) | 353 (98.1) |
| Does not cohabit | 687 (1.0) | 639 (1.9) | 48 (1.95) | 7 (1.95) |
| Place of delivery | ||||
| Urban† | 48 570 (53.7) | 46 681 (53.0) | 1889 (53.0) | 274 (51.3) |
| Rural | 41 882 (46.3) | 40 210 (47.0) | 1672 (47.0) | 260 (48.7) |
| Outcome | ||||
| Low birth weight (<2500 g) | 2731 (3.0) | 2612 (3.0) | 119 (3.8) | 19 (3.6) |
| Preterm birth (<37 weeks) | 3886 (4.3) | 3715 (4.3) | 171 (4.8) | 29 (5.4) |
| Small for gestational age | 8528 (9.4) | 8162 (9.4) | 336 (9.4) | 59 (11.0) |
| Spontaneous abortion | 33 55 (3.7) | 3181 (3.7) | 174 (4.9) | 27 (5.1) |
| Stillbirth | 288 (0.3) | 271 (0.3) | 17 (0.5) | 3 (0.6) |
| APGAR score <7 | 605 (0.7) | 586 (0.7) | 19 (0.5) | 1 (0.2) |
*
p Values <0.05 stratified by injury status and calculated by χ2 test: maternal age, parity, maternal smoking, alcohol consumption, household socioeconomic status and partner cohabitation status.
†
Urban residence includes Aarhus, Gentolle, Fredericksburg, Odense, Aalborg.
‡
Missing values: gestational age =184, birth weight =389, sex of child =90, parity =5765, smoking =1155, cohabitation status =22 920.