Table 3 Comparison of socio-demographic characteristics in the 3 GWG groups according to IOM recommendations
| Â | Gestational weight gain category | Â | ||
|---|---|---|---|---|
Inadequate | Adequate | Excessive | P-value | |
N (%) | 787 (24.8) | 1309 (41.3) | 1076 (33.9) | Â |
Race | Â | Â | Â | 0.060 |
 Han | 773 (98.2) | 1272 (97.2) | 1037 (96.4) |  |
 Minorities | 14 (1.8) | 37 (2.8) | 39 (3.6) |  |
Age (years) | Â | Â | Â | 0.004 |
  <  20 | 23 (2.9) | 44 (3.4) | 39 (3.6) |  |
  ~ 20 | 77 (9.8) | 127 (9.7) | 114 (10.6) |  |
  ~ 25 | 317 (40.3) | 616 (47.1) | 540 (50.2) |  |
  ~ 30 | 266 (33.8) | 370 (28.3) | 272 (25.3) |  |
  ~ 35 | 84 (10.7) | 126 (9.6) | 91 (8.5) |  |
  ≥ 40 | 20 (2.5) | 26 (2.0) | 20 (1.9) |  |
Education level | Â | Â | Â | 0.267 |
 Elementary school or below | 3 (0.4) | 10 (0.8) | 6 (0.6) |  |
 Middle school | 122 (15.5) | 201 (15.4) | 170 (15.8) |  |
 High school | 170 (21.6) | 247 (18.9) | 238 (22.1) |  |
 College or university | 430 (54.6) | 749 (57.2) | 605 (56.2) |  |
 Postgraduate degree | 58 (7.4) | 94 (7.2) | 54 (5.0) |  |
 Ph.D. degree | 4 (0.5) | 8 (0.6) | 3 (0.3) |  |
Region | Â | Â | Â | 0.002 |
 South | 318 (40.4) | 476 (36.4) | 349 (32.4) |  |
 North | 469 (59.6) | 833 (63.6) | 727 (67.6) |  |
Census register type | Â | Â | Â | 0.041 |
 Urban | 352 (44.7) | 570 (43.5) | 424 (39.4) |  |
 Rural | 435 (55.3) | 739 (56.5) | 652 (60.6) |  |
Occupation | Â | Â | Â | 0.134 |
 Unemployed | 231 (29.4) | 358 (27.3) | 340 (31.6) |  |
 Managerial workers | 83 (10.5) | 135 (10.3) | 101 (9.4) |  |
 Professional and technical workers | 124 (15.8) | 223 (17) | 157 (14.6) |  |
 Clerical workers | 75 (9.5) | 139 (10.6) | 98 (9.1) |  |
 Merchant or service workers | 145 (18.4) | 252 (19.3) | 210 (19.5) |  |
 Farming or fishing workers | 22 (2.8) | 15 (1.1) | 27 (2.5) |  |
 Others | 107 (13.6) | 187 (14.3) | 143 (13.3) |  |
Family member | Â | Â | Â | 0.215 |
 1 | 8 (1.0) | 11 (0.8) | 18 (1.7) |  |
 2 | 221 (28.1) | 393 (30.0) | 337 (31.3) |  |
 3 | 176 (22.4) | 290 (22.2) | 240 (22.3) |  |
 4 | 168 (21.3) | 317 (24.2) | 240 (22.3) |  |
 5 | 158 (20.1) | 217 (16.6) | 175 (16.3) |  |
  ≥ 6 | 53 (6.7) | 75 (5.7) | 59 (5.5) |  |
 Missing | 3 (0.4) | 6 (0.5) | 7 (0.7) |  |
Self-income (10,000 RMB (1410 USD)/year) | Â | Â | Â | 0.294 |
  ≤ 1 | 118 (15.3) | 155 (11.9) | 148 (13.9) |  |
 1–2 | 70 (9.1) | 120 (9.2) | 118 (11.1) |  |
 2–4 | 196 (25.4) | 349 (26.8) | 303 (28.5) |  |
 4–6 | 211 (27.3) | 365 (28.1) | 276 (26) |  |
 6–8 | 55 (7.1) | 96 (7.4) | 76 (7.1) |  |
 8–10 | 80 (10.3) | 138 (10.6) | 95 (8.9) |  |
  > 10 | 43 (5.6) | 77 (5.9) | 47 (4.4) |  |
Family-income (10,000 RMB (1410 USD) /year) | Â | Â | Â | 0.028 |
  ≤ 10 | 410 (53.2) | 725 (55.9) | 640 (60.4) |  |
 10–20 | 254 (32.9) | 411 (31.7) | 305 (28.8) |  |
  > 20 | 107 (13.9) | 162 (12.5) | 114 (10.8) |  |