Supplemental Table 5.
Births and events included in difference-in-differences analysis, Norway
| Events | 2020 |
2014–2019 |
||||||
|---|---|---|---|---|---|---|---|---|
| After March 12 |
Before March 12 |
After March 12 |
Before March 12 |
|||||
| n | (%) | n | (%) | n | (%) | n | (%) | |
| 16 wk | ||||||||
| All births | 16,879 | 14,960 | 111,027 | 91,651 | ||||
| Preterm birth | 919 | (5.4) | 931 | (6.2) | 6181 | (5.6) | 5466 | (6.0) |
| Medically- indicated | 417 | (2.5) | 416 | (2.8) | 2571 | (2.3) | 2263 | (2.5) |
| Spontaneous | 502 | (3.0) | 515 | (3.4) | 3610 | (3.3) | 3203 | (3.5) |
| Very preterm birth | 156 | (0.9) | 157 | (1.0) | 996 | (0.9) | 918 | (1.0) |
| 12 wk | ||||||||
| All births | 12,487 | 11,488 | 82,158 | 72,844 | ||||
| Preterm birth | 685 | (5.5) | 723 | (6.3) | 4580 | (5.6) | 4274 | (5.9) |
| Medically indicated | 316 | (2.5) | 326 | (2.8) | 1931 | (2.4) | 1769 | (2.4) |
| Spontaneous | 369 | (3.0) | 397 | (3.5) | 2649 | (3.2) | 2505 | (3.4) |
| Very preterm birth | 122 | (1.0) | 115 | (1.0) | 776 | (0.9) | 710 | (1.0) |
| 8 wk | ||||||||
| All births | 8190 | 7971 | 54,359 | 51,521 | ||||
| Preterm birth | 457 | (5.6) | 487 | (6.1) | 3032 | (5.6) | 2879 | (5.6) |
| Medically- indicated | 218 | (2.7) | 230 | (2.9) | 1287 | (2.4) | 1194 | (2.3) |
| Spontaneous | 239 | (2.9) | 257 | (3.2) | 1745 | (3.2) | 1685 | (3.3) |
| Very preterm birth | 70 | (0.9) | 84 | (1.1) | 533 | (1.0) | 480 | (0.9) |
| 4 wk | ||||||||
| All births | 3939 | 4080 | 26,440 | 25,668 | ||||
| Preterm birth | 216 | (5.5) | 231 | (5.7) | 1493 | (5.6) | 1473 | (5.7) |
| Medically- indicated | 95 | (2.4) | 97 | (2.4) | 650 | (2.5) | 611 | (2.4) |
| Spontaneous | 121 | (3.1) | 134 | (3.3) | 843 | (3.2) | 862 | (3.4) |
| Very preterm birth | 39 | (1.0) | 42 | (1.0) | 263 | (1.0) | 245 | (1.0) |
| 2 wk | ||||||||
| All births | 1941 | 2065 | 12,964 | 12,596 | ||||
| Preterm birth | 111 | (5.7) | 100 | (4.8) | 739 | (5.7) | 687 | (5.5) |
| Medically- indicated | 48 | (2.5) | 39 | (1.9) | 311 | (2.4) | 272 | (2.2) |
| Spontaneous | 63 | (3.2) | 61 | (3.0) | 428 | (3.3) | 415 | (3.3) |
| Very preterm birth | 20 | (1.0) | 17 | (0.8) | 128 | (1.0) | 116 | (0.9) |
Oakley et al. Preterm birth and COVID-19 mitigation measures in Scandinavia. Am J Obstet Gynecol 2022.