Skip to main content

Table 1 Socio-demographic and pre-pregnancy characteristics of study participants

From: Pregnancy complications among nulliparous and multiparous women with advanced maternal age: a community-based prospective cohort study in China

Variables Overall Maternal age groups (years) p
20–24 25–29 30–34 ≥35
(n) (10,171) (3274) (4587) (1637) (572)  
Residential area (n, %)       < 0.001
 Urban 1437 (14.1) 396 (12.1) 742 (16.2) 222 (13.6) 68 (11.9)  
 Rural 8734 (85.9) 2878 (87.9) 3845 (83.8) 1415 (86.4) 504 (88.1)  
Family per capita annual income (Chinese Yuan, n, %)       0.004
 ≤ 10,000 1647 (16.2) 550 (16.8) 684 (14.9) 267 (16.3) 124 (21.7)  
 10,001–20,000 4147 (40.8) 1409 (43.0) 1805 (39.4) 660 (40.3) 223 (39.0)  
 20,001–30,000 2871 (28.2) 922 (28.2) 1345 (29.3) 442 (27.0) 141 (24.7)  
 ≥ 30,001 1506 (14.8) 393 (12.0) 753 (16.4) 268 (16.4) 84 (14.7)  
Education level (n, %)       < 0.001
 Junior high school or lower 8511 (83.7) 2822 (86.2) 3604 (78.6) 1456 (88.9) 532 (93.0)  
 High school/college 1660 (16.3) 452 (13.8) 983 (21.4) 181 (11.1) 40 (7.0)  
Occupation (n, %)       < 0.001
 Farmer 1413 (13.9) 398 (12.2) 582 (12.7) 285 (17.4) 134 (23.4)  
 Housewife 5521 (54.3) 1768 (54.0) 2447 (53.3) 924 (56.4) 317 (55.4)  
 Factory worker 2395 (23.5) 819 (25.0) 1121 (24.4) 339 (20.7) 97 (17.0)  
 Other 842 (8.3) 289 (8.8) 437 (9.5) 89 (5.4) 24 (4.2)  
Pre-pregnancy BMI (kg/m2, n, %)       < 0.001
 < 18.5 1834 (18.0) 713 (21.8) 836 (18.2) 205 (12.5) 50 (8.7)  
 18.5–23 6247 (61.4) 2028 (61.9) 2854 (62.2) 994 (60.7) 317 (55.4)  
 23–27.5 1792 (17.6) 461 (14.1) 764 (16.7) 382 (23.3) 168 (29.4)  
 ≥ 27.5 298 (2.9) 72 (2.2) 133 (2.9) 56 (3.4) 37 (6.5)  
Gravidity (n, %)       < 0.001
 None 3878 (38.1) 1861 (56.8) 1708 (37.2) 203 (12.4) 26 (4.5)  
 Once or more pregnancies 6293 (61.9) 1413 (43.2) 2879 (62.8) 1434 (87.6) 546 (95.5)  
Parity (n, %)       < 0.001
 None 5354 (52.6) 2445 (74.7) 2406 (52.5) 344 (21.0) 65 (11.4)  
 Once or more births 4817 (47.4) 829 (25.3) 2181 (47.5) 1293 (79.0) 507 (88.6)  
History of miscarriage (n, %)       < 0.001
 None 6903 (67.9) 2506 (76.5) 3129 (68.2) 927 (56.6) 256 (44.8)  
 Once 1988 (19.5) 563 (17.2) 891 (19.4) 390 (23.8) 130 (22.7)  
 Twice or more times 1280 (12.6) 205 (6.3) 567 (12.4) 320 (19.5) 186 (32.5)  
History of induced abortion (n, %)       < 0.001
 None 9854 (96.9) 3218 (98.3) 4451 (97.0) 1546 (94.4) 538 (94.1)  
 Once or more times 317 (3.1) 56 (1.7) 136 (3.0) 91 (5.6) 34 (5.9)  
History of preterm labor (n, %)       0.007
 None 10,110 (99.4) 3262 (99.6) 4562 (99.5) 1620 (99.0) 565 (98.8)  
 Once or more times 61 (0.6) 12 (0.4) 25 (0.5) 17 (1.0) 7 (1.2)