Demographic and socioeconomic characteristic of study population according to maternal employment status
| Maternal employment status, n (%) | P value for differences | ||||||||
| All n (%) | Regular workers | Dispatched workers | Part-time workers | Self-employed workers | Non-employed | Others | |||
| 76 822 (100.0) | 27 228 (35.4) | 1395 (1.8) | 15 986 (20.8) | 2440 (3.2) | 27 869 (36.3) | 1904 (2.5) | |||
| Depressive symptomatology | |||||||||
| EPDS score ≥9 | 6741 (8.8) | 2188 (8.0) | 147 (10.5) | 1489 (9.3) | 187 (7.7) | 2538 (9.1) | 192 (10.1) | <0.001 | |
| EPDS score ≥13 | 1167 (1.5) | 348 (1.3) | 25 (1.8) | 286 (1.8) | 32 (1.3) | 445 (1.6) | 31 (1.6) | <0.001 | |
| Age (years) | |||||||||
| ≤24 | 6406 (8.3) | 1701 (6.3) | 110 (7.9) | 1572 (9.8) | 89 (3.7) | 2748 (9.9) | 186 (9.8) | <0.001 | |
| 25–34 | 49 248 (64.1) | 18 189 (66.8) | 919 (65.9) | 10 205 (63.8) | 1288 (52.8) | 17 402 (62.4) | 1245 (65.4) | ||
| ≥35 | 21 168 (27.6) | 7338 (27.0) | 366 (26.2) | 4209 (26.3) | 1063 (43.6) | 7719 (27.7) | 473 (24.8) | ||
| Educational attainment | |||||||||
| High school or less | 26 020 (33.9) | 6171 (22.7) | 575 (41.2) | 6866 (43.0) | 800 (32.8) | 11 027 (39.6) | 581 (30.5) | <0.001 | |
| Vocational school | 17 911 (23.3) | 7601 (27.9) | 235 (16.9) | 3612 (22.6) | 606 (24.8) | 5503 (19.8) | 354 (18.6) | ||
| Junior college | 15 095 (19.7) | 5171 (19.0) | 272 (19.5) | 3018 (18.9) | 491 (20.1) | 5690 (20.4) | 453 (23.8) | ||
| More than university | 17 691 (23.0) | 8248 (30.3) | 309 (22.2) | 2470 (15.5) | 538 (22.1) | 5611 (20.1) | 515 (27.1) | ||
| Missing | 105 (0.1) | 37 (0.1) | 4 (0.3) | 20 (0.1) | 5 (0.2) | 38 (0.1) | 1 (0.1) | ||
| Household equivalent income (yen) | |||||||||
| Quantile | Low: Q1 | 21 710 (28.3) | 3234 (11.9) | 348 (25.0) | 6323 (39.6) | 900 (36.9) | 10 394 (37.3) | 511 (26.8) | <0.001 |
| Q2 | 16 861 (22.0) | 4872 (17.9) | 378 (27.1) | 4226 (26.4) | 546 (22.4) | 6362 (22.8) | 477 (25.1) | ||
| Q3 | 20 683 (26.9) | 7908 (29.0) | 437 (31.3) | 3842 (24.0) | 474 (19.4) | 7475 (26.8) | 547 (28.7) | ||
| High: Q4 | 17 568 (22.9) | 11 214 (41.2) | 232 (16.6) | 1595 (10.0) | 520 (21.3) | 3638 (13.1) | 369 (19.4) | ||
| Parity | |||||||||
| Yes | 52 577 (68.4) | 15 413 (56.6) | 719 (51.5) | 11 366 (71.1) | 1866 (76.5) | 22 104 (79.3) | 1109 (58.3) | <0.001 | |
| No | 23 902 (31.1) | 11 688 (42.9) | 671 (48.1) | 4543 (28.4) | 565 (23.2) | 5648 (20.3) | 787 (41.3) | ||
| Missing | 343 (0.5) | 127 (0.5) | 5 (0.4) | 77 (0.5) | 9 (0.4) | 117 (0.4) | 8 (0.4) | ||
| Living with partner | |||||||||
| Yes | 72 214 (94.0) | 25 266 (92.8) | 1262 (90.5) | 14 859 (93.0) | 2315 (94.9) | 26 816 (96.2) | 1696 (89.1) | <0.001 | |
| No | 4608 (6.0) | 1962 (7.2) | 133 (9.5) | 1127 (7.1) | 125 (5.1) | 1053 (3.8) | 208 (10.9) | ||
| Living with parents | |||||||||
| Yes | 15 820 (20.6) | 5621 (20.6) | 315 (22.6) | 3609 (22.6) | 695 (28.5) | 5083 (18.2) | 497 (26.1) | <0.001 | |
| No | 61 002 (79.4) | 21 607 (79.4) | 1080 (77.4) | 12 377 (77.4) | 1745 (71.5) | 22 786 (81.8) | 1407 (73.9) | ||
| Marital status | |||||||||
| Married | 74 008 (96.3) | 26 147 (96.0) | 1283 (92.0) | 15 172 (94.9) | 2365 (96.9) | 27 265 (97.8) | 1776 (93.3) | <0.001 | |
| Unmarried | 2113 (2.8) | 877 (3.2) | 88 (6.3) | 557 (3.5) | 52 (2.1) | 440 (1.6) | 99 (5.2) | ||
| Divorce | 501 (0.7) | 126 (0.5) | 18 (1.3) | 204 (1.3) | 16 (0.7) | 119 (0.4) | 18 (1.0) | ||
| Bereavement | 10 (0.0) | 5 (0.0) | 0 (0.0) | 3 (0.0) | 0 (0.0) | 2 (0.0) | 0 (0.0) | ||
| Missing | 190 (0.3) | 73 (0.3) | 6 (0.4) | 50 (0.3) | 7 (0.3) | 43 (0.2) | 11 (0.6) | ||
| Mental health status | |||||||||
| 0≤K6 score <5 | 55 230 (71.9) | 19 903 (73.1) | 963 (69.0) | 11 486 (71.9) | 1765 (72.3) | 19 746 (70.9) | 1367 (71.8) | <0.001 | |
| 5≤K6 score <13 | 21 592 (28.1) | 7325 (26.9) | 432 (31.0) | 4500 (28.2) | 675 (27.7) | 8123 (29.2) | 537 (28.2) | ||
| Perceived level of social support | |||||||||
| High | 35 905 (46.7) | 13 284 (48.8) | 584 (41.9) | 6851 (42.9) | 1155 (47.3) | 13 146 (47.2) | 885 (46.5) | <0.001 | |
| Low | 40 917 (53.3) | 13 944 (51.2) | 811 (58.1) | 9135 (57.1) | 1285 (52.7) | 14 723 (52.8) | 1019 (53.5) | ||
EPDS, Edinburgh Postnatal Depression Scale; K6, Kessler Psychological Distress Scale.