Table 1.
Characteristics of participants according to mode of delivery.
| Vaginal delivery | Cesarean section | |||
|---|---|---|---|---|
| (n = 53,186) | (n = 12,049) | |||
| n | (%) | n | (%) | |
| Age, y | ||||
| <25 | 4486 | (8.4) | 609 | (5.1) |
| 25–<30 | 15,578 | (29.3) | 2493 | (20.7) |
| 30–<35 | 19,473 | (36.6) | 4249 | (35.3) |
| ≥35 | 13,421 | (25.2) | 4615 | (38.3) |
| Missing | 228 | (0.4) | 83 | (0.7) |
| Body mass index, kg/m2 | ||||
| <18.5 | 9068 | (17.1) | 1521 | (12.6) |
| 18.5–<25 | 39,669 | (74.6) | 8699 | (72.2) |
| ≥25 | 4418 | (8.3) | 1819 | (15.1) |
| Missing | 31 | (0.1) | 10 | (0.1) |
| Parity | ||||
| 0 | 22,792 | (42.9) | 5192 | (43.1) |
| 1 | 19,264 | (36.2) | 4492 | (37.3) |
| ≥2 | 9792 | (18.4) | 2057 | (17.1) |
| Missing | 1338 | (2.5) | 308 | (2.6) |
| Gestational age, week | ||||
| <34 | 178 | (0.3) | 407 | (3.4) |
| 34–<37 | 1484 | (2.8) | 863 | (7.2) |
| 37–<42 | 51,424 | (96.7) | 10,716 | (88.9) |
| ≥42 | 100 | (0.2) | 63 | (0.5) |
| Pregnancy complication | ||||
| No | 44,920 | (84.5) | 9434 | (78.3) |
| Yes | 7310 | (13.7) | 2380 | (19.8) |
| Missing | 956 | (1.8) | 235 | (2.0) |
| Obstetric complications | ||||
| No | 29,095 | (54.7) | 5415 | (44.9) |
| Yes | 23,187 | (43.6) | 6402 | (53.1) |
| Missing | 904 | (1.7) | 232 | (1.9) |
| Marital status | ||||
| Married | 51,073 | (96.0) | 11,621 | (96.5) |
| Unmarried | 1453 | (2.7) | 278 | (2.3) |
| Divorced/widowed | 241 | (0.5) | 75 | (0.6) |
| Missing | 419 | (0.8) | 75 | (0.6) |
| Highest education level, y | ||||
| ≤9 | 1657 | (3.1) | 397 | (3.3) |
| >9–≤12 | 15,254 | (28.7) | 3604 | (29.9) |
| >12–≤16 | 22,913 | (43.1) | 5263 | (43.7) |
| >16 | 12,914 | (24.3) | 2651 | (22.0) |
| Missing | 448 | (0.8) | 134 | (1.1) |
| Employment status | ||||
| No | 23,971 | (45.1) | 5467 | (45.4) |
| Yes | 28,623 | (53.8) | 6408 | (53.2) |
| Missing | 592 | (1.1) | 174 | (1.4) |
| Annual household income, JPY | ||||
| <4 million | 18,849 | (35.4) | 4158 | (34.5) |
| 4–<6 million | 16,975 | (31.9) | 3772 | (31.3) |
| ≥6 million | 13,929 | (26.2) | 3329 | (27.6) |
| Missing | 3433 | (6.5) | 790 | (6.6) |
| Smoking status | ||||
| Never | 32,566 | (61.2) | 7036 | (58.4) |
| Quit | 18,445 | (34.7) | 4475 | (37.1) |
| Current | 1618 | (3.0) | 390 | (3.2) |
| Missing | 557 | (1.1) | 148 | (1.2) |
| Alcohol intake | ||||
| Never | 17,934 | (33.7) | 3999 | (33.2) |
| Former | 33,280 | (62.6) | 7592 | (63.0) |
| Current | 1391 | (2.6) | 294 | (2.4) |
| Missing | 581 | (1.1) | 164 | (1.4) |
| Regular physical activity | ||||
| No | 12,377 | (23.3) | 3072 | (25.5) |
| Yes | 40,473 | (76.1) | 8869 | (73.6) |
| Missing | 336 | (0.6) | 108 | (0.9) |
| Experience of stressful event | ||||
| No | 29,957 | (56.3) | 6811 | (56.5) |
| Yes | 22,695 | (42.7) | 5092 | (42.3) |
| Missing | 534 | (1.0) | 146 | (1.2) |
| Negative attitude toward pregnancy | ||||
| No | 49,165 | (92.4) | 11,246 | (93.3) |
| Yes | 3578 | (6.7) | 723 | (6.0) |
| Missing | 443 | (0.8) | 80 | (0.7) |
| Degree of emotional social support | ||||
| Low | 14,454 | (27.2) | 3354 | (27.8) |
| Mid–low | 10,798 | (20.3) | 2440 | (20.3) |
| Mid–high | 14,422 | (27.1) | 3209 | (26.6) |
| High | 12,525 | (23.6) | 2800 | (23.2) |
| Missing | 987 | (1.9) | 246 | (2.0) |
| Kessler psychological distress scale (K6) score | ||||
| 0–4 | 38,558 | (72.5) | 8776 | (72.8) |
| 5–12 | 12,958 | (24.4) | 2821 | (23.4) |
| ≥13 | 1339 | (2.5) | 348 | (2.9) |
| Missing | 331 | (0.6) | 104 | (0.9) |
| Area of residence | ||||
| A | 4160 | (7.8) | 1019 | (8.5) |
| B | 4627 | (8.7) | 944 | (7.8) |
| C | 6822 | (12.8) | 1567 | (13.0) |
| D | 2964 | (5.6) | 724 | (6.0) |
| E | 3730 | (7.0) | 613 | (5.1) |
| F | 3761 | (7.1) | 766 | (6.4) |
| G | 3223 | (6.1) | 617 | (5.1) |
| H | 3017 | (5.7) | 681 | (5.7) |
| I | 2218 | (4.2) | 535 | (4.4) |
| J | 4123 | (7.8) | 978 | (8.1) |
| K | 2724 | (5.1) | 654 | (5.4) |
| L | 1668 | (3.1) | 376 | (3.1) |
| M | 3153 | (5.9) | 1046 | (8.7) |
| N | 4223 | (7.9) | 849 | (7.1) |
| O | 2773 | (5.2) | 680 | (5.6) |
Abbreviation: K6, Kessler psychological distress scale.