Table 1.
Characteristics of primipara between 1995 and 2019
| Variables | VD | CD | Total | P-value |
|---|---|---|---|---|
| Maternal | ||||
| Year | < 0.0001 | |||
| 1995–1999 | 6725 (6.9) | 2825 (3.5) | 9550 (5.4) | |
| 2000–2004 | 6525 (6.7) | 5165 (6.5) | 11,690 (6.6) | |
| 2005–2009 | 13,266 (13.6) | 15,933 (19.9) | 29,199 (16.4) | |
| 2010–2014 | 28,931 (29.6) | 26,324 (32.9) | 55,255 (31.1) | |
| 2015–2019 | 42,315 (43.3) | 29,659 (37.1) | 71,974 (40.5) | |
| Season | < 0.0001 | |||
| Spring | 23,396 (23.9) | 19,993 (25.0) | 43,389 (24.4) | |
| Summer | 25,272 (25.9) | 20,525 (25.7) | 45,797 (25.8) | |
| Autumn | 25,774 (26.4) | 20,283 (25.4) | 46,057 (25.9) | |
| Winter | 23,320 (23.9) | 19,105 (23.9) | 42,425 (23.9) | |
| Age (years) | < 0.0001 | |||
| < 20 | 429 (0.4) | 187 (0.2) | 616 (0.4) | |
| 20–24 | 15,747 (16.1) | 8587 (10.8) | 24,334 (13.7) | |
| 25–29 | 61,980 (63.4) | 45,060 (56.4) | 107,040 (60.3) | |
| 30–34 | 18,398 (18.8) | 21,831 (27.3) | 40,229 (22.6) | |
| > 34 | 1208 (1.2) | 4241 (5.3) | 5449 (3.1) | |
| GDP per capita (¥) | < 0.0001 | |||
| < 30,000 | 14,976 (15.3) | 9896 (12.4) | 24,872 (14.0) | |
| 30,000–60,000 | 15,781 (16.1) | 19,079 (23.9) | 34,860 (19.6) | |
| 60,000–90,000 | 16,924 (17.3) | 15,111 (18.9) | 32,035 (18.0) | |
| 90,000–120,000 | 24,722 (25.3) | 16,735 (20.9) | 41,457 (23.3) | |
| > 120,000 | 25,359 (25.9) | 19,085 (23.9) | 44,444 (25.0) | |
| Gestational age (weeks) | < 0.0001 | |||
| < 37 | 5455 (5.6) | 7146 (8.9) | 12,601 (7.1) | |
| 37–41 | 91,826 (93.9) | 72,296 (90.5) | 164,122 (92.4) | |
| > 41 | 481 (0.5) | 464 (0.6) | 945 (0.5) | |
| Gravidity | < 0.0001 | |||
| 1 | 65,608 (67.1) | 48,327 (60.5) | 113,935 (64.1) | |
| 2–3 | 29,936 (30.6) | 28,185 (35.3) | 58,121 (32.7) | |
| > 3 | 2218 (2.3) | 3394 (4.3) | 5612 (3.2) | |
| Fetus number | < 0.0001 | |||
| Singleton | 97,588 (99.8) | 77,754 (97.3) | 175,342 (98.7) | |
| Multiparous | 174 (0.2) | 2152 (2.7) | 2326 (1.3) | |
| Complications | < 0.0001 | |||
| Yes | 21,355 (21.8) | 36,803 (46.1) | 58,158 (32.7) | |
| No/Unclassified | 76,407 (78.2) | 43,103 (53.9) | 119,510 (67.3) | |
| Neonatal | ||||
| Position | < 0.0001 | |||
| Head | 97,075 (99.5) | 69,374 (89.2) | 166,449 (94.9) | |
| Breech | 202 (0.2) | 7723 (9.9) | 7925 (4.5) | |
| Other | 21 (0) | 226 (0.3) | 247 (0.1) | |
| Unclassified | 290 (0.3) | 431 (0.6) | 721 (0.4) | |
| Sex | < 0.0001 | |||
| Male | 49,846 (51.1) | 41,537 (53.4) | 91,383 (52.1) | |
| Female | 47,730 (48.9) | 36,212 (46.6) | 83,942 (47.9) | |
| Unclassified | 12 (0) | 5 (0) | 17 (0) | |
| Weight (g) | < 0.0001 | |||
| 1000–1500 | 327 (0.3) | 260 (0.3) | 587 (0.3) | |
| 1500–2499 | 3173 (3.3) | 3910 (5.0) | 7083 (4.0) | |
| 2500–3999 | 90,850 (93.1) | 65,328 (84.0) | 156,178 (89.1) | |
| 4000–4499 | 3116 (3.2) | 7290 (9.4) | 10,406 (5.9) | |
| > 4499 | 122 (0.1) | 966 (1.2) | 1088 (0.6) | |
Abbreviations: VD Vaginal delivery, CD Cesarean delivery