Table 1 Characteristics of participants by prepregnancy BMI and rate of gestational weight gain
| Â | Prepregnancy BMI | Gestational weight gain rate | |||||||
|---|---|---|---|---|---|---|---|---|---|
Underweight | Normal weight | Overweight | Obese | P value | Insufficient | Adequate | Excessive | P value | |
Participants, n (%) | 1787 (20.0) | 6006 (67.3) | 961 (10.8) | 172 (1.9) | Â | 2018 (22.6) | 2449 (27.4) | 4459 (50.0) | Â |
prepregnancy BMI, kg/m2, median (IQR) | 17.6 (16.9,18.1) | 20.6 (19.5,21.9) | 25.1 (24.4,26.0) | 29.4 (28.7,31.2) | < 0.001 | 20.0 (18.3, 22.0) | 20.2 (18.8,22.0) | 20.5 (19.1,22.8) | < 0.001 |
Gestational weight gain rate, kg/w, median (IQR) | 0.42 (0.34,0.51) | 0.40 (0.33,0.50) | 0.35 (0.26,0.44) | 0.29 (0.21,0.41) | < 0.001 | 0.27 (0.19, 0.33) | 0.44 (0.38,0.48) | 0.63 (0.56,0.75) | < 0.001 |
Age, years, median (IQR) | 27 (25,30) | 28 (26,31) | 29 (27,32) | 28 (26,31) | < 0.001 | 28 (25, 31) | 28 (26, 31) | 28 (26, 30) | 0.005 |
Gestational age at delivery, week | 39 (38, 40) | 39 (38,40) | 39 (38,40) | 39 (38,40) | 0.183 | 39 (38, 40) | 39 (38, 40) | 39 (38, 40) | < 0.001 |
Education |  |  |  |  | 0.205 |  |  |  | < 0.001 |
 High school and below | 1198 (67.0) | 3914 (65.2) | 650 (67.6) | 119 (69.2) |  | 1415 (70.1) | 1576 (64.4) | 2890 (64.8) |  |
 College or graduate school | 589 (33.0) | 2092 (34.8) | 311 (32.4) | 53 (30.8) |  | 603 (29.9) | 873 (35.6) | 1569 (35.2) |  |
Drinking during pregnancy | Â | Â | Â | Â | 0.570 | Â | Â | Â | 0.084 |
 Yes | 52 (2.9) | 160 (2.7) | 24 (2.5) | 2 (1.2) |  | 40 (2.0) | 67 (2.7) | 131 (2.9) |  |
 No | 1735 (97.1) | 5846 (97.3) | 937 (97.5) | 170 (98.8) |  | 1978 (98.0) | 2382 (97.3) | 4328 (97.1) |  |
Smoking during pregnancy | Â | Â | Â | Â | 0.358 | Â | Â | Â | 0.904 |
 Yes | 5 (0.3) | 37 (0.6) | 4 (0.4) | 1 (0.6) |  | 11 (0.6) | 14 (0.6) | 22 (0.5) |  |
 No | 1782 (99.7) | 5969 (99.4) | 957 (99.6) | 171 (99.4) |  | 2007 (99.4) | 2435 (99.4) | 4437 (99.5) |  |
Passive smoking |  |  |  |  | < 0.001 |  |  |  | 0.721 |
 Yes | 408 (22.8) | 1182 (19.7) | 167 (17.4) | 44 (25.6) |  | 420 (20.8) | 489 (20.0) | 892 (20.0) |  |
 No | 1379 (77.2) | 4824 (80.3) | 794 (82.6) | 128 (74.4) |  | 1598 (79.2) | 1960 (80.0) | 3567 (80.0) |  |
Annual household income, yuan | Â | Â | Â | Â | 0.009 | Â | Â | Â | 0.752 |
  < 10,000 | 1426 (79.8) | 4799 (79.9) | 766 (79.7) | 147 (85.5) |  | 1609 (79.7) | 1961 (80.1) | 3568 (80.0) |  |
 10,001–20,000 | 239 (13.4) | 885 (14.7) | 156 (16.2) | 20 (11.6) |  | 306 (15.2) | 358 (14.6) | 636 (14.3) |  |
  > 20,000 | 122 (6.8) | 322 (5.4) | 39 (4.1) | 5 (2.9) |  | 103 (5.1) | 130 (5.3) | 255 (5.7) |  |
Number of parity |  |  |  |  | < 0.001 |  |  |  | < 0.001 |
 Primiparous | 1552 (86.9) | 4904 (81.7) | 710 (73.9) | 125 (72.7) |  | 1559 (77.3) | 2001 (81.7) | 3731 (83.7) |  |
 Multiparous | 235 (13.1) | 1102 (18.3) | 251 (26.1) | 47 (27.3) |  | 459 (22.7) | 448 (18.3) | 728 (16.3) |  |
Gestational diabetes mellitus |  |  |  |  | < 0.001 |  |  |  | 0.279 |
 Yes | 100 (5.6) | 539 (9.0) | 163 (17.0) | 52 (30.2) |  | 176 (8.7) | 233 (9.5) | 445 (10.0) |  |
 No | 1687 (94.4) | 5467 (91.0) | 798 (83.0) | 120 (69.8) |  | 1842 (91.3) | 2216 (90.5) | 4014 (90.0) |  |
PIH |  |  |  |  | < 0.001 |  |  |  | < 0.001 |
 Yes | 44 (2.5) | 237 (3.9) | 82 (8.5) | 29 (16.9) |  | 52 (2.6) | 84 (3.4) | 256 (5.7) |  |
 No | 1743 (97.5) | 5769 (96.1) | 879 (91.5) | 143 (83.1) |  | 1966 (97.4) | 2365 (96.6) | 4203 (94.3) |  |