Supplemental Table 3.
Characteristics of births in Sweden by year, 2014 to 2020
| Characteristics | All |
2014 |
2015 |
2016 |
2017 |
2018 |
2019 |
2020 |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | (%) | n | (%) | n | (%) | n | (%) | n | (%) | n | (%) | n | (%) | n | (%) | |
| All births | 713,121 | 89,437 | 102,483 | 107,877 | 104,314 | 104,556 | 102,937 | 101,517 | ||||||||
| Gestational age (wk) | ||||||||||||||||
| Extremely preterm <28 | 2670 | (0.4) | 374 | (0.4) | 401 | (0.4) | 432 | (0.4) | 370 | (0.4) | 349 | (0.3) | 385 | (0.4) | 359 | (0.4) |
| Very preterm 28–<32 |
3912 | (0.5) | 537 | (0.6) | 579 | (0.6) | 601 | (0.6) | 590 | (0.6) | 553 | (0.5) | 530 | (0.5) | 522 | (0.5) |
| Moderate or late preterm 32–<37 | 33,264 | (4.7) | 4231 | (4.7) | 4869 | (4.8) | 5095 | (4.7) | 4924 | (4.7) | 4822 | (4.6) | 4740 | (4.6) | 4583 | (4.5) |
| Term 37–<42 |
636,182 | (89.2) | 79,221 | (88.6) | 90,605 | (88.4) | 95,382 | (88.4) | 92,699 | (88.9) | 93,240 | (89.2) | 92,464 | (89.8) | 92,571 | (91.2) |
| Postterm ≥42 |
36,113 | (5.1) | 5074 | (5.7) | 6029 | (5.9) | 6367 | (5.9) | 5731 | (5.5) | 5592 | (5.3) | 4818 | (4.7) | 2482 | (2.4) |
| Maternal age | ||||||||||||||||
| <20 | 7266 | (1.0) | 1078 | (1.2) | 1139 | (1.1) | 1332 | (1.2) | 1073 | (1.0) | 1052 | (1.0) | 880 | (0.9) | 712 | (0.7) |
| 20–24 | 75,668 | (10.6) | 10,980 | (12.3) | 12,347 | (12.0) | 12,560 | (11.6) | 11,245 | (10.8) | 10,551 | (10.1) | 9542 | (9.3) | 8443 | (8.3) |
| 25–29 | 223,444 | (31.3) | 27,130 | (30.3) | 32,283 | (31.5) | 34,390 | (31.9) | 33,200 | (31.8) | 33,358 | (31.9) | 32,116 | (31.2) | 30,967 | (30.5) |
| 30–34 | 246,949 | (34.6) | 30,619 | (34.2) | 34,198 | (33.4) | 35,722 | (33.1) | 35,387 | (33.9) | 36,401 | (34.8) | 36,762 | (35.7) | 37,860 | (37.3) |
| 35–39 | 128,099 | (18.0) | 15,742 | (17.6) | 18,126 | (17.7) | 19,087 | (17.7) | 18,713 | (17.9) | 18,719 | (17.9) | 18,864 | (18.3) | 18,848 | (18.6) |
| ≥40 | 31,484 | (4.4) | 3846 | (4.3) | 4350 | (4.2) | 4739 | (4.4) | 4667 | (4.5) | 4459 | (4.3) | 4750 | (4.6) | 4673 | (4.6) |
| Missing | 211 | (0.0) | 42 | (0.0) | 40 | (0.0) | 47 | (0.0) | 29 | (0.0) | 16 | (0.0) | 23 | (0.0) | 14 | (0.0) |
| Parity | ||||||||||||||||
| 0 | 306,085 | (42.9) | 38,527 | (43.1) | 43,770 | (42.7) | 45,903 | (42.6) | 44,576 | (42.7) | 45,179 | (43.2) | 44,202 | (42.9) | 43,928 | (43.3) |
| ≥1 | 402,892 | (56.5) | 49,654 | (55.5) | 57,305 | (55.9) | 60,709 | (56.3) | 59,674 | (57.2) | 59,329 | (56.7) | 58,675 | (57.0) | 57,546 | (56.7) |
| Missing | 4144 | (0.6) | 1256 | (1.4) | 1408 | (1.4) | 1265 | (1.2) | 64 | (0.1) | 48 | (0.0) | 60 | (0.1) | 43 | (0.0) |
| Multiple birth | ||||||||||||||||
| Yes | 10,072 | (1.4) | 1278 | (1.4) | 1490 | (1.5) | 1553 | (1.4) | 1528 | (1.5) | 1423 | (1.4) | 1378 | (1.3) | 1422 | (1.4) |
| No | 703,049 | (98.6) | 88,159 | (98.6) | 100,993 | (98.5) | 106,324 | (98.6) | 102,786 | (98.5) | 103,133 | (98.6) | 101,559 | (98.7) | 100,095 | (98.6) |
| Country of birth | ||||||||||||||||
| Scandinavia | 467,815 | (65.6) | 60,828 | (68.0) | 67,377 | (65.7) | 69,920 | (64.8) | 67,965 | (65.2) | 68,250 | (65.3) | 67,212 | (65.3) | 66,263 | (65.3) |
| Outside Scandinavia | 179,445 | (25.2) | 18,114 | (20.3) | 22,380 | (21.8) | 27,908 | (25.9) | 27,816 | (26.7) | 28,306 | (27.1) | 28,165 | (27.4) | 26,756 | (26.4) |
| Missing | 65,861 | (9.2) | 10,495 | (11.7) | 12,726 | (12.4) | 10,049 | (9.3) | 8533 | (8.2) | 8000 | (7.7) | 7560 | (7.3) | 8498 | (8.4) |
| Maternal education status (y) | ||||||||||||||||
| ≤9 | 51,858 | (7.3) | 5755 | (6.4) | 6980 | (6.8) | 8559 | (7.9) | 8358 | (8.0) | 7991 | (7.6) | 7432 | (7.2) | 6783 | (6.7) |
| 10–12 | 224,867 | (31.5) | 27,970 | (31.3) | 32,128 | (31.3) | 34,644 | (32.1) | 33,884 | (32.5) | 33,877 | (32.4) | 32,363 | (31.4) | 30,001 | (29.6) |
| >12 | 312,802 | (43.9) | 36,877 | (41.2) | 41,699 | (40.7) | 46,019 | (42.7) | 46,105 | (44.2) | 47,504 | (45.4) | 46,928 | (45.6) | 47,670 | (47.0) |
| Missing | 123,594 | (17.3) | 18,835 | (21.1) | 21,676 | (21.2) | 18,655 | (17.3) | 15,967 | (15.3) | 15,184 | (14.5) | 16,214 | (15.8) | 17,063 | (16.8) |
| Season of conceptiona | ||||||||||||||||
| Winter | 186,013 | (26.1) | 21,807 | (24.4) | 26,372 | (25.7) | 28,483 | (26.4) | 27,433 | (26.3) | 27,811 | (26.6) | 27,198 | (26.4) | 26,909 | (26.5) |
| Spring | 189,348 | (26.6) | 25,970 | (29.0) | 26,713 | (26.1) | 28,191 | (26.1) | 27,303 | (26.2) | 27,457 | (26.3) | 27,164 | (26.4) | 26,550 | (26.2) |
| Summer | 170,177 | (23.9) | 23,824 | (26.6) | 24,751 | (24.2) | 25,388 | (23.5) | 24,377 | (23.4) | 24,336 | (23.3) | 23,824 | (23.1) | 23,677 | (23.3) |
| Fall | 167,583 | (23.5) | 17,836 | (19.9) | 24,647 | (24.0) | 25,815 | (23.9) | 25,201 | (24.2) | 24,952 | (23.9) | 24,751 | (24.0) | 24,381 | (24.0) |
| BMI (kg/m2) | ||||||||||||||||
| <18.5 | 17,126 | (2.4) | 2321 | (2.6) | 2555 | (2.5) | 2595 | (2.4) | 2361 | (2.3) | 2525 | (2.4) | 2479 | (2.4) | 2290 | (2.3) |
| 18.5–<25 | 376,453 | (52.8) | 50,470 | (56.4) | 56,329 | (55.0) | 57,239 | (53.1) | 52,041 | (49.9) | 54,522 | (52.1) | 53,377 | (51.9) | 52,475 | (51.7) |
| 25–<30 | 175,120 | (24.6) | 20,763 | (23.2) | 24,398 | (23.8) | 25,938 | (24.0) | 24,557 | (23.5) | 26,380 | (25.2) | 26,518 | (25.8) | 26,566 | (26.2) |
| 30–<35 | 67,469 | (9.5) | 7599 | (8.5) | 9042 | (8.8) | 9567 | (8.9) | 9682 | (9.3) | 10,446 | (10.0) | 10,386 | (10.1) | 10,747 | (10.6) |
| ≥35 | 29,541 | (4.1) | 3027 | (3.4) | 3826 | (3.7) | 4179 | (3.9) | 4225 | (4.1) | 4558 | (4.4) | 4749 | (4.6) | 4977 | (4.9) |
| Missing | 47,412 | (6.6) | 5257 | (5.9) | 6333 | (6.2) | 8359 | (7.7) | 11,448 | (11.0) | 6125 | (5.9) | 5428 | (5.3) | 4462 | (4.4) |
| Smoking in early pregnancy | ||||||||||||||||
| No | 655,643 | (91.9) | 83,360 | (0.0) | 95,519 | (93.2) | 99,123 | (91.9) | 90,388 | (86.6) | 97,014 | (92.8) | 95,835 | (93.1) | 94,404 | (93.0) |
| Yes | 30,331 | (4.3) | 4529 | (0.0) | 5031 | (4.9) | 4789 | (4.4) | 4272 | (4.1) | 4219 | (4.0) | 3874 | (3.8) | 3617 | (3.6) |
| Missing | 27,147 | (3.8) | 1548 | (0.0) | 1933 | (1.9) | 3965 | (3.7) | 9654 | (9.3) | 3323 | (3.2) | 3228 | (3.1) | 3496 | (3.4) |
BMI, body mass index.
Oakley et al. Preterm birth and COVID-19 mitigation measures in Scandinavia. Am J Obstet Gynecol 2022.
a
Winter (December–February); Spring (March–May); Summer (June–August); Fall (September–November).