Table 1 Demographic and clinical characteristics of the study population stratified by prepregnancy BMI
Maternal and neonatal variables, mean (SD) or n (%) | Overall (N = 5275) | Underweight (n = 729) | Normal weight (n = 3896) | Overweight/Obese a (n = 650) | P-value |
|---|---|---|---|---|---|
Maternal age, years | 32.8 (4.4) | 30.9 (4.0) | 33.1 (4.4) | 33.8 (4.4) |  < 0.001 |
Education level |  |  |  |  |  < 0.001 |
 High school or below | 722 (13.7) | 87 (11.9) | 523 (13.4) | 112 (17.2) |  |
 College or university | 3547 (67.2) | 520 (71.3) | 2634 (67.6) | 393 (60.5) |  |
 Postgraduate | 557 (10.6) | 64 (8.8) | 430 (11.0) | 63 (9.7) |  |
 Unknown | 449 (8.5) | 58 (8.0) | 309 (7.9) | 82 (12.6) |  |
Pre-pregnancy BMI, kg/m2 | Â | Â | Â | Â | - |
 Underweight | 729 (13.8) | 729 (100) | - | - |  |
 Normal weight | 3896 (73.9) | - | 3896 (100) | - |  |
 Overweight | 568 (10.8) | - | - | 568 (87.4) |  |
 Obese | 82 (1.6) | - | - | 82 (12.6) |  |
Family history of diabetes, yes | 727 (13.8) | 80 (11.0) | 544 (14.0) | 103 (15.8) | 0.03 |
Parity, ≥ 2 | 2724 (51.6) | 264 (36.2) | 2069 (53.1) | 391 (60.2) |  < 0.001 |
PWG, kg | 7.1(3.6) | 7.5 (3.0) | 7.2 (3.5) | 5.6 (4.4) |  < 0.001 |
Weeks of PWG, wk | 25.5 (1.4) | 25.6 (1.5) | 25.5 (1.4) | 25.4 (1.5) | 0.05 |
Last prenatal weight, kg | 66.7 (8.9) | 57.5 (5.4) | 66.4 (7.0) | 79.0 (8.6) |  < 0.001 |
Weeks of last weight, kg | 38.5 (1.4) | 38.52(1.4) | 38.5 (1.4) | 38.5 (1.3) | 0.99 |
WGR in late 2nd and 3rd trimesters, wg/wk | 0.37 (0.2) | 0.39 (0.2) | 0.37 (0.2) | 0.35 (0.2) |  < 0.001 |
 Below IOM | 2576 (48.8) | 462 (63.4) | 1918 (49.2) | 196 (30.2) |  < 0.001 |
 Within IOM | 1398 (26.5) | 157 (21.5) | 1103 (28.3) | 138 (21.2) |  |
 Above IOM | 1301 (24.7) | 110 (15.1) | 875 (22.5) | 316 (48.6) |  |
Hospital admission, yes | 266 (5.0) | 27 (3.7) | 200 (5.1) | 39 (6.0) | 0.13 |
Sex, female | 2472 (46.9) | 356 (48.8) | 1829 (46.9) | 287 (44.2) | 0.23 |
Birth weight, gram | 3201 (413) | 3061 (360) | 3207 (409) | 3324 (447) |  < 0.001 |
Clinical outcomes | |||||
 LGA, yes | 227 (4.3) | 7 (1.0) | 155 (4.0) | 65 (10.0) |  < 0.001 |
 Macrosomia, yes | 154 (2.9) | 4 (0.5) | 109 (2.8) | 41 (6.3) |  < 0.001 |
 SGA, yes | 680 (12.9) | 164 (22.5) | 469 (12.0) | 47 (7.2) |  < 0.001 |
 LBW yes | 198 (3.8) | 31 (4.3) | 150 (3.9) | 17 (2.6) | 0.231 |